for... Skyking...

[GMAs]

Hey I thought that a ppt presentation would work out for sending across the web... but....

So here you are... you answer to your question about the Waist gate clean out kit...

If you look at the picture of the actuator in the service manual you will see that it is comprised of a inlet... unfilterd nat... a orfice... where the dirt usually gets stuck in... a piston...a big spring.... and a outlet... which goes to the controler..

Now we have been thru the way the system works before so we won't cover that here... you already know what happens when... so lets just look at the actuator and how to clean it without taking it out...

What you will need....

Your compression checker.. the thing you check your cyc compression/blowdown ... it has a regulator on it as well as a on off air valve...

You will need a clean small paint pot... or some other canister that can stand up to 60 lbs pressure on it... tubing/pipe..etc... and can be filled with a cleaning fluid... stodard solvent, gas.. etc... fire here is the key word... as we are going to creat a enviroment that can be damaging if care is not taken... sort of a risk management kind of things... not to be done in a hangar ...

You will need a couple of fittings with some alu tubing already flaired so that you can attach them to the Outlet of the paint pot... to the OUTLET of the actuator... and some clamps...to keep the hose from blowing off...

and you will need some hose...to connect the thing up... we use tigon hose... some can use nlyon and other may want to use plain old rubber hose... that is clean inside...

How it all goes togeather......

Remove the and clean out the lines from the actuator.. and remove the inlet fitting gaining access to the chamber where the orfice hole is drilled... (note the direction it was facing and the number of threads showing above the locking nut...

You connect your compression tester to the air supply... it then in turn has the on off valve that goes to the regulator... which is set for 60 lbs... not 80 that you use for testing the cyc's... this output then goes to the paint pot or in some cases we have seen them use just a longer piece of tigon tubing that is loaded with gas or cleaning fluid.... the end of the paint pot..(liquid output) is attached to the OUTPUT of the waist gate... so that when we apply the pressure.. we get fluid that is forced backwards into the actuator... which then will flush out the orfice and clean out the piston and cyc area...

Ok you say.. but will that clean it out ... well yes and no....

you have to remove the small inlet fitting on the actuator so that all the dirt can be blown out without any being left in the bottom of the inlet orfice area... otherwise if you didn't take the fitting out.. and it has a o ring on it... so you need to look at 43.13 for how to tighten them back up correctly.... you could have some dirt still stuck in it....

Look but, never try and force a piece of wire down into the orfice... as all you will do is get the dirt piece stuck in the controller and now you will have other problems...

Ok .. why only 60 lbs.... of air pressure.. well your oil system operates on that that most of the time... and when you bring the air on line.. its going to force the piston down to the bottom of the actuator... if you used more pressure you might take the chance of blowing the piston seal... not good... so we limit ourselves to 60 lbs...of air pressure... and let it flow.. till the fluid is all forced thru.. and air is the only thing left coming out... which will dry the cleaning fluid/gas.... and no you can not use anything else... sorry... you will hurt the seals if you do...

When you get done.. look with a inspection mirror down into the actuators inlet... with a light it should look clean... if not repeat the process again...

This should save lots of time for taking the thing appart and putting it back togeather again... sure it makes a mess but, its less time finishing and cleaning the engine with a spray gun than taking the bolts out and removing the actuator...

Now if dirt gets up into the controller.. your on your own... as this is much more than just flushing it thru.... Gary Main down at Main turbo has told me many times at the maintaince meetings that he has seen the skymasters have more problems with wear and dirt in their contollers than just about any other plane... and it seems to wear the control pins... faster...

Here my suggestion is that you take it off and send it to him... as he has the necessary set up tools and shop to do the job... it runs about 500 buck to have one gone thru... and overhauled... so you want to make sure the oil is clean.. another reason we say to use the 25 hr rule... but, others will say thats not economical... OK...

Oh and when you go to put the inlet fitting back in the actuator.. you might want to go look at the part on setting the O ring.... yes their is a special way to do it...

And when done have your mechanic make sure the lines are not twisted, kinked or otherwise... leaking or could leak...

We have found that if you start to get dirt/parts of carbon.. which start to block up the inlet orfice... you might want to pull the plug on the bottom of the accessory case... the big one... along with the oil filter adapter.. and clean out the bottom of the casting... as you can be sure that if their was one speck... of carbon their.. that their are others just waiting... to make the trip down the hose to the actuator.... smile...

runing the engine and keeping the system clean is the best way... change the oil often is the other... and lastly... flying the plane and maintaing it is the last.... the actuators do get plugged up... and we have asked for permission to change the line to the "flitered oil" but, it seems that they are recluant to make any changes...even though the early engines has a tap on the main feed of oil to the engine gally where the oil pressure line attaches...(this was filtered oil)... to many lawyers... I guess... so we have been working on a inline filter assembly that would/could be put on as a STC thing... but, that takes time and with the small few in numbers.. that would need it.... is un-econimically sound.. sorry...

Hope this helps... it would be better if I could show you the pictures of the stuff.. and how we do it... usually takes about 30 min to clean both.. front and rear... and oh ya.. this is a pilot/owner/ helping the mechanic kinda thing... so you do have to have him around.. when you do it.. but, hey he may learn something and not charge you for his time... smile.. GMAs...

[Don Hickman]

GMAS,

I was a little distressed to read the last part of your post. Are you saying that the oil line filter thing for the turbos is not going to happen? I have lost track of the number of times I've had to clean out the darn thing! Seems like most every time we change the oil on the front engine I then have no turbo on takeoff. So I taxi back and we clean out the thing per your recommendations and then the turbo works fine until the next oil change. (25 hours)

So, I've been waiting for word that the STC has been obtained so I could ge those filters for both engines. Is this going to happen or am I doomed to continual cleaning?

[Bob Cook]

Don

I have NEVER needed to do this EVER. Make sure you keep the engines lean as possible on the ground and as much as possible in the air.
I change the oil after 25 hrs and oil and filter at 50.

Perhaps you have some crap left over from the previous owner like Skyking.

Keep them LEAN AND MEAN!

BTW did you see the new ad for the BMW "mini". Saw a billboard that said "quit using your middle finger buy a mini"..............

bob

[Don Hickman]

Bob, I change oil just as you do and I run as lean as I can. My mechanic says its just lots of stuff coming loose because the engine is finally being run regularly whereas before I bought it, 25 hours was a big year. But I keep thinking that surely whatever deposits are in that engine have to all come out! Not yet, however. Just had to clean the actuator last week after my last oil change. Runs fine now.

Leaving for Mexico in the morning. Catch you in a couple of weeks.

[GMAs]

I will keep the pressure on the FAA to see if we can get a approval for the modification if you are still interested.... I have the data... and I think I can get Cont engine to come around... and approve the instalation of the filter in line... or the other.. would be to install a T in the oil pressure sender line.. where it is filtered oil... like the early ones had... either way.. we should be able to come up with a change... so that it keeps the units as well as the finer stuff from wearing out the controllers as fast.. as the skymasters/360 engines seem to have a higher rate of overhauls than most other engines... due to the filtered oil vs. the non-like the skymaster does...

Will keep you informed as to which way the ball bounces... didn't think anyone was interested in adding the filter anymore... oppsss sorry... get right on it boss.... GMAs...

[Don Hickman]

Yes, definitely interested. Will buy 2 as soon as they are available! I've already had to replace one controller and I'm tired of losing the front turbo every time I change the oil. Bob Cook just must be a much better pilot than I am!

[Bob Cook]

Don

I am no better pilot! I think that you are now cleaning out the engine after a length of inactivity and perhaps a lot of carbon buildup. As you are aware you need to run the engines above 180 deg oil temp for one hour minimum to burn off the moisture etc. Those trips to Mexico is what it needs.

GMAS
Sounds like I would be very interested as well. It is a good idea having a couple of filters (in parallel) to avoid this problem.

Like Don, I rarely run less than two hours at any one time with at least 68% power.

Hopefully Don is just about over this problem. I think Skyking finally sorted out the problem as well.

Bob

[SkyKing]

Hey Don,

Your experience with no turbo boost AFTER the oil change on the front engine is the same scenario on this end, except the turbo on mine finally came alive after rotation to about 30" and then VERY slowly came up to 35" in the downwind climbout. I was surprised to hear you're having the same problems. You'd think that with fresh oil and a new oil filter that the problem wouldn't be there. How many hours on your front engine? Mine sat quite a bit too before I got it. Our front engine is 1250 TTSN.

And Bob... NO, it's still not sorted out but I'm sure glad to hear you NEVER have these turbo problems, as it is apparently only Don and I that have the "Carbon Gunk Meister" in our engines (HA!-HA!). And BTW, when you comin' out this way??

Anyway, FRONT engine: FIRST FLIGHT after oil & filter change, no turbo boost on the takeoff roll until after rotation, then slow spool. After climbing to 4000', 29"/2400 RPM cruise, then pushing the throttle up turbo responds but it spools up more slowly than the rear engine, which has 140 hrs TT. Came back and landed after an hour-long flight, belly clean as a whistle. I'd put 7-quarts in during the oil change.

SECOND FLIGHT a few days later... oil level during preflight was 5.5 quarts, so added 1-quart. OK turboboost at the initation of the takeoff roll, although 35-36" is all she'd do with 126PPH on fuel flow. Did a 33"/2450 RPM/92 PPH climb @ 125-130 KIAS up to 17,500 and began noticing a slightly nervous MP needle going through anout 14,000. Hit the yellow boost pump and releaned to 92PPH and MP seemed to stabilize. In cruise at 17,500 with OAT of 20 Degrees F, ran 30" MP, 2400 RPM, and 82 PPH. Cyl head temps about 2 needle widths of 400 degrees. Now, here's what was interesting: while in cruise at 17,500, pushing up the front throttle (with some enrichening of the mixture too), I notice the MP begin oscillating back and forth between 30" and 37/38" with fuel flow following. Oil pressure at the edge of the top green and steady, no fluctuations seen. Bring throttle back to 30" and with yellow boost on, everythings fine and steady. Does this sound like maybe a dirty controller?

After a slow descent with power up to keep the cyl head temps constant, and upon landing, noticed the breather let loose a whole bunch of oil down the belly. 30-Minutes after shutdown oil level is back down to 5.6 quarts, so it appears almost a quart sprayed down the belly, up into the rear wheel area and across the top and bottom of the rear stabilizer. Checking the front oil cap, it's wet underneath and down the sides of the oil filler neck, and I discover also that the dip-stick O-ring is missing. Wonder if that had anything to do with the oil loss?

Anyway, waiting for a new O-ring for the dipstick and a new oil cap gasket as it doesn't feel like its tight enough, maybe its allowing upper plenum pressurized air to exert some effect on the breather. And yes, I have separators.

Don, do you get any oil scum and where do you run your oil levels???

Still sorting out the problems. BTW, during the oil change, just a couple of bits of carbon in the recessed portion of the oil plug. Have yet to cut the filter open, but I'm sure we'll find some carbon. Gee, did I leave anything out? 1977 P337.

SkyKing

[Mark Hislop]

I don't know if this will help on the quest for an STC for an inline filter on the controller line, but here goes. I just read a posting on another site from a 414 driver. He had a MP problem that he was trying to resolve. One of the questions that was asked of him was if he had a RAM conversion, because RAM puts inline filters in the oil line leading to the contoller. (They also said that the filters plug up fairly often, and RAM was thinking of eliminating them. I don't understand that...I'd rather clean/replace a filter than have to clean out the contoller inlet.) GMAS, does this help to get an STC approved for the 360? Is it possible that there filter might already be usable for our engines?

Mark

[SkyKing]

Mark,

Are you plagued by the same "Carbon Gunk Meister" that Don and I are experiencing problems with, insofar as turbo boost problems after oil changes?

I'll query a friend of mine who also flies a RAM converted C-414 and see if he can shed any light on this.

SkyKing

[Kevin McDole]

Fortunately, I have not had this problem.

Something sounds strange to me. Why does changing the oil cause this problem to occur? Are you sure you aren't introducing some other problem, such as air in the oil lines?

[Bob Cook]

MP problems

Kevin has not mentioned any problems either. This problem seems to be isolated and not "in mass". Other than Skyking I don't know if it has been brought up over the past couple of years.

It was not a concern at any of the CPA courses. If it is only at takeoff then perhaps the oil is cool, or one of the oil lines have some restriction that is not normal..

What has new oil to do with a controller malfuction?

beats me

Bob

[Mark Hislop]

JR:

So far (4 years in my 73 P337) I've never had the problem. I have one factory reman (about 150 hours on it now, replaced an engine that had 1000 hours, running good but the crankcase cracked) and one mid-time (800 hours) engine. The oil in the mid-time engine gets black very quickly after an oil change, which I assume is carbon from the combustion process. I use Aeroshell 15W50 year round, except when breaking in the new engine, when I used mineral oil. I do not lean aggressively, since I feel that gas is cheaper than maintenance. Unfortunately, I don't put as many hours on the plane as I would like...probably 50-75 per year. Based on all of that, you would think I would be a prime candidate for this carbon fouling problem. However, even though it hasn't happened to me, if GMAS says it happens, I believe it. Maybe it's like gear up accidents...there is those that have and those that will.

Let us know what your 414 friend has to say.

Mark

[Mitch Taylor]

Skyking:

What did the dipstick read after you added 7 quarts and ran the engine a little while? My dipsticks read a quart lower than what's actually in the engines. If I have seven quarts in the engines (stick reads 6) oil use is about 1 quart per 9 hours. If I run at 7 on the dipstick, I get oil out the breather, and lose that top quart very quickly. You should check the stick right after changing the oil and doing a runup. Let it stand overnight and check it again, as you'll probably see at least half a quart more after standing overnight. Now you'll have a better idea in any given situation how much oil is actually in the engines.

Mitch
N5251Z (O-2A)

[Don Hickman]

Skyking,

Regarding oil levels, I try to keep it between 6-7 quarts. If I go above 7, it blows out quickly, just like Mitch Taylor said. And I'm tired of cleaning the belly of the plane! I also have the mysterious vanishing and reappearing quart.

Regarding the controller, I'm now wondering why it is that Skyking and I appear to be the only ones having this problem. There must be others or GMAS wouldn't have brought it up and wouldn't have developed a method for cleaning it out. All I know is that my front engine keeps clogging the controller and my rear doesn't. And it has happened at times other than right after an oil change, but an oil change is guaranteed to bring it on. The front engine oil is always a lot dirtier than the rear. Of course, it's 100 hours past TBO but compressions are still good, oil analysis shows normal and everything else seems to be ok with it so I don't see any reason to replace it just yet although any of that could change at any moment and then I'm looking for a new engine. Rear engine has 300 hours to go to TBO. I suppose when I replace the front engine this controller problem will disappear. Still, I would think filtered oil to the controller would be better than the current setup.

[GMAs]

interesting that some are and some are not....

but, Don and King... you are not alone... it happens to more than not...

MOst of the new engines will not get the crud till they get about mid life... why... because they have to develope the carbon on the back side of the piston... ya all them pistons have oil blasted on the back sides of them to help keep them cool and from melting a hole in the middle... ahhh that agressive leaning... does wonders for the heat on the dome of the piston... and without the extra fuel... to help cool it... well.. it compounds the problem...

so why does it happen after that and a oil change... well its thought that the carbon is built up during flight... now while the engine is running along.. the filter gets any of the particles that get washed off as the engine is running... i.e. they are kept in the flow until they hit the filter... and get trapped... now when you put new oil in.. they have detergents that are much more active... as the oil gets older... they wear out first... one reason we say change at 25 hr intervals.. keeps the engine cleaner...inside.. and that is why your oil gets dirty... its the stuff in suspension... its supposed to do that... but, now when you don't fly enough or it sits for a while.. the alu shucks the carbon off the back of the piston while it starts to corrode... and when you start up.. the oil is nice and thick... so the flow is down... and it gives the big rocks of carbon time to settle out in the chambers... well your pick up for the waist gate actuator and controller is right at the bottom of the accessory case .. right where the oil is GOIN into the filter... and slows down... so it settels out and heads for the orffice to do a plug up job..... now on the early skymsters till 72 they used filtered oil from the main feed galley over on the left side of the engine where the oil pressure is taken from... but, they claim that presented problems for the engine... so they moved it back to the accessory case bottom.. and put the fitting thru the plug cap...

So you guys who are flying a lot and on a regular interval... are keeping your engines cleaner insides because the oil is making the trip thru the filter while hot and thin.... but, just because you use 15-50... your not immune from the creeping crud... no actually you are more prone to get it quicker.. as the oil is thiner and it will drop the larger rocks and small children out quicker...than the good old 50 wt oil... but, both have a life limit on the detergents that are in them... and how long they will stay active depends on the amount of dirt, conditions of operation and temp the engine goes thru...

filters are good because they can take a larger amount of the crud before they plug up... and I disagree with cont engine on the fact that it would do damage if it does...after all it does now... and it doesn't do any damage except make the trubo engine a normal.... so I think they are a help... but, they come back with... ya but, its two more hose fittings and something else to leak... Ok... but, if done correctly and maintained it should not present any more problem than the one way valve on the turbo... after all its about the same looking kinda device...

So for you that don't have the problem...YET... your lucky.. but, for those who do...your not alone... we see at least half of the fleet we work on have the problem as age and non use sets in... it get higher in numbers... and yes it does occur right after the oil change because of the new detergents working on the insides...

As to oil and stick levels... you need to go back to the Cont engine site and look up the SID on the dip sitcks.. and how the manufacture wants you to check for proper reading levels... yes they are not all correct.. as their are different lengths of indicator tapes... the part that goes in the engine... to show what the level is... and they want you to check... sometimes the tubing slips on the hose part and will make it longer or shorter which in turn makes it read more full or less...

Hope this helps.. ya understand why the carbon is a problem in the 360 engine... GMAs...

[kevin]

Skyking asked me to post a response to this thread. My experience is as follows:

First, I have a 73 P337. I use straight 50 wt detergent oil in the summer and 40 wt in the winter (Aeroshell). I try to fly evey week, although sometimes there is a 2 or 3 week gap between flights.

My experience with my high time engines (800 and 1600) is the same as with my current low time engines (100 and 200). The high time engines sat for about six months before I bought the airplane (no flight time at all), but before that and since the airplane has been flown actively for most of it's life.

I have not experienced the carbon buildup thing. I do not have a problem after I change the oil. I change the oil and filter at 25 - 35 hour intervals.

All five engines that I have had on my P337, and both engines on my 65 C337, all exhibited the same dipstick behavior. If you fill above six quarts, the oil goes on the belly. Therefore, I wait until the dipstick reads five quarts or slightly below, and then I add a quart. My flight instructor, who has 600+ hours in C337 and T337 aircraft flying checks at night says that this was the normal behavior in the aircraft that he flew as well.

Most of my P337 flying is done between 12,000 and 20,000 feet. I climb at 31" and 2500 RPM, mixture full rich during the whole climb. In cruise, I run 50 degrees rich of peak on the first cylinder to peak, although I am currently reevaluating that choice. Fuel flow in climb is about 110 PPH. I have no problems with MP fluctuations on either engine.

CHT in winter (Pacific Northwest) runs 340 during climb, 290 - 300 in cruise (EI CHT gauge). In the hottest of conditions, 100+ ambient on the ground, I will see 375 in climb and 340 at high altitude cruise.

I hope I hit all the points that folks are interested in. If you have any other questions, please let me know.

Kevin

[SkyKing]

Kevin,

Interesting info on your climb MP of 31" and 2500 RPM with full rich mixture... probably a LOT easier on the engines. I note that Cessna's POH recommends 33"/2450 with mixtures pulled back to 90 PPH, and the American Intercooler paperwork recommends the same 33"/2450 for climb, but 100PPH on fuel flow. Think I'll try your settings except for a little leaning, at least to 90PPH, and then enrichen if necessary for cylinder head cooling.

My IA mechanic keeps telling me that if I want to see my engines last, he recommends NOT using MAX takeoff power of 37" and 2800 RPM... unless it's an Emergency. He stresses that anything over 31" on these TSIO-360's is playing with fire. Any thoughts on this? I guess if you're not loaded to full gross, pushing the engines to 37" each time is unnecessary wear and tear. I know, the POH says 37/2800 for the takeoff, but that is presumably based on full gross weight.

What are your cruise parameters for those 12,000 to 20,000' flights in terms of MP, RPM and FUEL FLOWs?

SkyKing

[kevin]

On the "not full power takeoff" thing, I just don't agree. I run 35" and 2800 (full) RPM, (35" because of the intercoolers) during takeoff, then back off to 31 and 2500 for climb. I have read and heard many fine arguements on why full power takeoffs are best, and never heard a decent argument for why not, except a vague "your pushing the engine too hard". I've been running the engines this way for seven years, but in the end, like most things in general aviation, who really knows. Maybe I am just lucky. I am sure some more knowledgable folks will chime in with opinions in both directions...

Oh, and I guess the rear turbo did come apart on me on an 800 hour engine, therefore proving that full power takeoffs are bad (although it came apart in cruise). On the other hand, my front engine had over 1650 hours on in and was still working great when I replaced it, therefore proving that full power takeoffs are good...

Most of my takeoffs are at gross weight, or very close.

To 17,000, I use 27"/2400 RPM. FL180 and above, I use 27" and 2450 RPM to keep pressurization going. I flight plan 10 ga for climb and then 25 GPH. I use less than that, but have only Cessna's fuel flow (really fuel pressure) gauge, which I do not trust. I suspect I am burning between 23 and 24 GPH.

I don't agree with leaning in climb. Leaning will reduce your margin against detonation, and saves so little fuel as to not be noticeable. I know the book says to do it, but at the power setting I described, my full rich fuel flow is about 110 pph, not far off of what the book suggests. In climb, I think richer is better. Again, what I have read and learned from others supports this, but I did not make a point of retaining the sources.

Kevin

[Don Hickman]

I'm in Mexico and have a slow (very!) internet connection so this will be brief. Just wanted to say that my experience in operating my 74 P337 parallels Kevin. I cruse at 27 and 2400 and burn right at 23 gal per hour. Climb is 31 and 2500 with 30 gal per hour. Temps stay ok. Take offs at full power. I hadn't considered upping the RPM to 2450 when above FL 180 but will try that on my way back across the Gulf.

And thanks, GMAS, for that explanation. Glad to know Skyking and I aren't the only ones with a carbon-turbo problem. Now I just hope my front turbo doesn't plug up when I go to take off from the island next week. That 2,000 ft strip on a hot day just doesn't look too good without a full boost on both engines! And the concrete wall at the end doesn't look too soft, either. But it's there, I suppose, to make sure I don't take out the local softball team which plays 50 feet from the end of the runway.

[Bob Cook]

I hate commercials, however, if you want to fix the carbon problem then my recommendation is to throw a can of AVBLEND into the engine and your carbon will be "immulsified".

No joking....... I am not kidding .......... and it is the truth.

I have thrown a can in every 50 hrs and maybe this is the reason for not having any problems.

You have nothing to lose as the cost is far less than paying someone to "blow your hoses"..

Sorry I forgot to mention this before.

And ... I have no relationship with AVBlend. AVblend in nothing more than highly refined mineral oil with a small amout of zylene in it (evaporates right away but makes it smell technical and expensive / of which it is........ expensive that is).



Bob

[SkyKing]

Hello Bob,

You ought to consider writing commercials for radio! That was such a great line: "Blow your hoses!"

Will give the Avblend some consideration, although we did use some Rislone and that seemed to do a VERY good job of cleaning out the engine and it felt smoother. Used a quart of it in place of one quart of AeroShell at oil change.

BTW, Bob, we never do run-ups until temp is at least 75F and never takeoff until warmed above 100F... just like the TCM manual recommends, so it's not a "cool oil" thing that's contributing to the problem on the takeoff.

The weird part of this anomally is that once airborne and in cruise, pushing up the front engine throttle results in normal turbo spools and good MP. I recall one time landing and after a brief shut down, restarted and tookoff and didn't get any turbo boost on the front until way into the climb. And of course all of this started occurring after we started flying the plane regularly.

Today we replaced the oil cap gasket on the front engine and it seems much tighter now, and installed a new O-ring on the dip stick... will probably fly tomorrow and we'll see what gives. Oil level is about 5.6 or 5.7, so will bring it just up to 6.0 -- had thought about Kevin's 5.5 quarts, but I can't bring myself to fly with less than 6.0 per the POH.

Say Don... I presume you flew direct from Indiana to Mexico... what part of Mexico? And what was your FL, enroute time and ground speeds?

SkyKing

[Bob Cook]

Skyking

AVblend does break down the carbon. GMAS, in my opinion, has hit the nail on the head. Radial engines have even a bigger problem with large carbon deposits plugging the screens.

I have no issue regarding take off oil temp. 180 degree temp during cruise does help to get rid of moisture which contributes to the carbon problem. Perhaps higher temp and higher oil pressures tend to dislodge the particles that were trapped.

I cannot say much but I have been dealing with a company that has been doing research on the subject. BTW seaplanes have the biggest problem, especially the "beavers".

Lots of flying seems to avoid the problem.

Bob

[Kim Geyer]

To you guys trying to clean your wastegates, some of the later model 337's use a metal seal instead of an O-ring and will most likely leak if reused. You can get new ones from Aircraft Spruce.
Also Gary Main told me that a good test for the waste gate is to cap the oil inlet and start pressurizing through the oil exit port, the waste gate should start opening @18 psi and be fully closed by 50 psi. this is a quick easy test.
Kim

[Kim Geyer]

Correction on my post
The waste gate should start closing at @18 psi
Kim

[SkyKing]

Kim,

The Cessna Parts Manual does not dilenate a "metal seal", it only shows the O-rings, so I'm curious where this metal seal is located... is this on the inlet side of the wastegate from the sump, or where? Do you happen to have a part number from Aircraft Spruce, or page number - I have the gold colored 2001-2002 catalog.

The wastegate is freely operating as ground checked and we keep the shaft on the butterfly regularly Mouse Milked. That it is closing properly, although late in the takeoff roll and in flight, is confirmed by our being able to obtain 35-36" MP.

However at the higher altitudes, like at 17,500 the other day, we were seeing these wide variations in MP when the front throttle was pushed up... oscillating gyrations between 31 and 37", but this was at 2450... didn't think to run the RPM up higher, which would probably have stopped it. I believe this osciallating behavior is called 'bootstrapping'. MP and fuel flow followed one another. Backing off to 31" at 2450 and MP/fuel flow was steady. We don't see this behavior at lower altitudes.

SkyKing

[SkyKing]

Kevin,

I think you're right on the oil levels... our 1250 hour front engine didn't throw anything on the belly with the oil level at about 5.5 to 5.7 quarts, oil pressure top green and normal temp, and after shutdown +30 minutes, oil level was the same... this was after a 1.5 hour flight to 10,000 at cruise with 2400 and 27".

Prior to flight we did replace the 1/8" TCM gasket on the front engine oil cap (P/N 533355), it now seems to be a tighter fit. Also replaced the O-ring on the dip stick (P/N AN123860).

And although the front engine spooled to 35" in the takeoff roll, it was slower than the rear. The front engine hesitated at 27" and then came up mid-way down the runway, so we didn't have the egnines 'synched' until almost liftoff. So, we're still studying this one. More and more I'm beginning to suspect the controller is the culprit instead of the wastegate.

SkyKing

[Kim Geyer]

Skyking
My parts book shows the metal seals or gaskets are used on s/n's 33701816 thru 33701907. the part #'s are AN901-6A and AN901-4A.
Also I have seen the butterfly valve in the wastegate become loose on the actuator shaft and would cause the manifold pressure to ossilate @ 4 in's eather way.
I just replaced a controller on one of our aircraft about 3 weeks ago because I just could not adjust it. Iwould have 30 in's or 38 in's nothing in between.
Hope this helps.
Kim

[SkyKing]

Kim,

No wonder... we're not even comparing the same airplane model! Ours is a P337, and you're referring to, apparently, a Turbo version of the 337G, as best I can figure from the serial numbers.

SkyKing

[GMAs]

Skyking your right... as you have garretts and the early ones were the older truck conversions made by Ray Jay.... but, actually the older ones would boost to a higher pressure... thus could actually get up higher... if you check the service height of the early turbos to yours... and not because you have a bleed off of pressure to the cabin.. you will see that they actually could go to 32,000 ft.. while the later T's it was limited to 28,000 because they ran out of boost... I once took one to 28,000 and it was not fun... but, I believe that the thing would have gone to 32 if I wasn't so frozen... you can't believe what the mountains look like from that alt... and how cold it can get inside the cabin... and how long it takes you to get back down... and quit shivering... I actually got fatague from shivering... and sore the next day... smile... I don't recomend that anyone go up their... even with the southwind heaters... they don't work... and when you think about engine heat... well their almost isn't any... so you have to point the nose down and power down to keep the heat up... fuel doesn't like to burn and flow.. etc...and you have to run the boost pumps on high... smile... GMAs

[Don Hickman]

Guys, I can't keep up with this board from down here in the Carribean!

But to answer Skyking's question, I fly from Bedford, IN (BFR) to New Orleans (NEW) and refuel. Takes about 03:30. Then from New Orleans direct to Cancun (MMUN) and that takes another 03:30. Groundspeed is usually right at 170 knots running 57% power at FL 180 or 190.

Now it's back to the beach!

[skymaster]

Howdy: The turbo filter works. The former owner designed a filter and recd caa 337. approaching 350 hours unmarked by crud. We fly 50 hrs between oil change. Exhaust leaks are another topic. I have sent the data and field approvals to GMAS. Hope it helps . James Henderson

[Don Hickman]

All right! Let's get one of those turbo filters! I just got back from Mexico. Stupid turbo wouldn't boost on the front engine at take off from my unpaved 2,000 foot strip. 30" was all I could get and, given the temps and load, I just did make it over the wall. But by the time I landed at Houston it had cured itself. Full power on takeoff when I no longer needed it!

So, if there's a filter out there for that oil line, I want one! Make that two.

[SkyKing]

Don,

If you would, please describe what your front engine gauges were showing during the takeoff roll from brake release at your unpaved strip, e.g., MP, RPM, fuel flow, oil press & temp. Any anomalies during the run-up, or normal? Did you get any turbo boost at all? Or, did it start coming up slowly during the takeoff roll, or after liftoff? And what about during climb and cruise?

What mine has typically done is come up to about 25-27" and just sits there at brake release, at full throttle, with the out-of-synch wow-wow between the front and rear. Then I get a slow turbo spool up to about 35" and 125-130PPH during the takeoff run. If I land somewhere and then restart and takeoff within say 30-minutes or an hour, I usually don't get any boost at all until after liftoff and in the climb, so I've been reluctant to go into any unimproved short strips.

The manuals say that if everything is rigged properly, you should have full-turbo boost with 2/23 throttle, which is the way things used to work and my rear engine always does, but we're pushing the front throttle all the way forward even to get the 25-27" prior to brake release. Leaving it at full throttle position, it eventually comes up to 35". The engines ususally get synched up and the wow-wow disappears just before liftoff. We've checked the rigging and everything seems fine.

Once into the climb or cruise, everything seems to work just like it's suppose to, i.e., normal throttle positions for a given MP, but the front reacts slight slower than the rear engine. Oil pressure is top green and temps at least 100F prior to takeoff. And normal cyl head temps. Normal indications during climbs and cruise. And I recall one day in cruise at 8,000' running the RPM's up to 2800 redline and bringing the throttles up and no problem acquiring 37" with full-rich mix. And as I noted in a previous post, the other day while at 17,500', noticed that when I pushed the front throttle up from 30" to full at 2400RPM, the MP wanted to oscillate between 33 and 38" like it was bootstrapping... but steady at 30" or 33" with 2400. I should have upped the RPM to see if it would have stabilized, but neglected to do so.

Do you have any of these kind of MP fluctuations at altitude, or are things rock steady?

Got to be some pesky carbon/grime in the system somewhere. Maybe it's the controller instead of the wastegate, as things work normally once airborne.

Be interested in your indications, throttle positions, MP's and RPM's. BTW, my front engine is at 1250 TTSN, and the rear at 150 SFRM. I'll have to check the logs, but it seems the front controller, and wastegate were overhauled a couple of years before I acquired the plane (and probably needlessly!), and I think the front turbo was replaced at 700 hours, but I'll have to check to make sure.

SkyKing

[Don Hickman]

Sky,

On takeoff Friday morning from the unpaved strip on the island the MP on the front engine only came up to 30" and never exceeded that. The rear ran up to redline and then backed off to 37" which is what it always does. So does the front when the turbo is working. MP dropped on the front as I climbed out but would hold at 27" at FL 180 with full throttle. Fuel flow during takeoff was 104 on the front, 140 on the rear.

Oil temps were above 100 at takeoff (heck, the ambient air was at 95!). I can't remember what the RPM was but it was above 2500 as I remember pulling it back to 2500 along with the rear.

While in cruise the MP would slowly cycle up and down by about 3" and the wow-wow would come and go. It's just impossible to keep the engines in sync. The rear would hold rock steady at 27" but the RPM would fluctuate which just drives me crazy.

When later taking off from Houston Hobby the front spooled up to redline, then past redline and pegged! I had to pull the throttle back to get it below redline then pushed the throttle full forward again and it held at 37" during takeoff. However, while in cruise it still runs up and down by about 3".

So tomorrow I'll be having another conversation with my mechanic but I assume that whatever piece of dirt or carbon that had plugged it up in Mexico worked it's way out by the time I was leaving Houston so there's probably nothing for the mechanic to do. But I don't understand why it blew completely past redline nor what is causing the up and down in MP while in cruise. And 27" is the maximum I can get out of it above 17,000. The turbo is brand new as the old one burned up during an unexpected engine shutdown during a missed approach two months ago and I've installed a new controller as well. But nothing has changed regarding performance even with the new equipment. Sometimes it works and sometimes it doesn't and it never holds steady no matter what.

I'm about 150 hours past TBO on the front engine and even though it's got good compression and isn't making metal I'm beginning to think I should just scrap it and put in a new one. I'm about out of ideas on how to fix the front turbo problem. And I have no idea why the rear prop won't hold a steady RPM. That engine still has 300 hours to go before TBO and everything works ok except for the RPM fluctuation. At least it gives me something to do while flying long legs across the Gulf of Mexico!

[Mark Hislop]

SkyKing:

I wonder if your problem isn't related to the prop governor, rather than the turbo controller. The disonnance you hear is related to engine speed. I can vary my MP quite a bit, and still keep the props in sync (although I've never tried it at takeoff). I'm not sure this fits all of the other symptoms you've described, but it might be worth looking at.

Mark

[GMAs]

Skyking is right... its not the trubo system... as it only controls the MP... RPM after 1800 is controlled by the prop govnr.... you might want to pull it and have it checked... bet you will find the little screen up at the inlet is kinda full of stuff too... as its a real fine stanless steel screen and it traps parts of the carbon so it doesn't go into the gov gears which increase the oil pressure to the prop piston which cause it to pitch... also if you have sagging oil pressure you might want to check with a master gauge...sometime s on the high time engines the galley way fills up with crud too... if the oil is not changed frequently... smile...

As to Skykings problem... you need to cap off the accuator and check for full operation... and no you can not fly it that way.... but, I would bet your problem is either with the accuator or controller...

And it does no good to clean out the accuator if you don't clean out the lines.. too... after all their is more of that stuff just waiting at the bottom of the accessory case lined up to hit the road thru the tunnel of the lines right back into the accuator... but, if in fact its not the accuator.. sorry .. your going to have to pull the controller and send it in ...

Now just for your info.. yes you can cap off the accuator.. and it will give you full turbo boost... and yes you can take off with it.. but, its called manual override.. and if you are not on the stick ... so to speek you can bend rods.. and do all kinds of nasty stuff to your engine... but, in a emergency...you can have the power if you need it.. and don't have a way to clean/clear the accuator... but, we don't recomend it... as others do.. because the system should work right all of the time or else don't fly... kinda thing...


As to the accessory screen/filters... seems that someone is going to have to make them.. as we are not able to get anyone around here that even wants to touch something that says Airplane on it.... James Hinderson sent me the drawings.. and that becomes another problem.. they seem to think that it might be infringment... gee... what next...

Skyking also has a set of the drawings... but, James if the guy who made them up might want to also make them up... I would like to hear from him... could you please ask... as it seems that the FAA is starting to come around and after many hours of talking they are saying good things... I gave them the old what ya going to do if it fails on take off.. with out it... then are you going to be responsible... and they shrugged their shoulders and all said... well.... maybe you have something their... great but, then who is going to make it up... is next... and how much are they going to cost each...

Cessna didn't respond with anything... nor did Cont engine so time is up.. now we can proceed with plans to go the 337 route... for field approval... but, we need a test pilot... for the first one... smile..kinda thing...

I look at it this way... if you have the accuator clog up now.. it blocks the oil flow... so if the screen clogs up... what is the difference... but, the screen would allow more to be trapped before it does... still doesn't relieve you of the maintance problem of keeping the engine clean... but, we are also looking into a oil route change too.. which would not require the filters at all ... so we'll keep you posted... stand by for News... as they say.. may be a topic at the next yearly meeting for the skymasters.... smile... GMAs...

[GMAs]

I forgot to mention... take both of them off and have the checked... togeather.. that way they can set them both on the same mach... or else you will have the dreaded control offset... and they won't be togeather... smile... hope this helps GMAs

[Bob Cook]

Don , Skyking

Investing 20 bucks on a can of AVBLEND is worth a shot!

This stuff came out of a patent some years ago called Lenkite. For some reason it breaks down carbon and you should see the results very quickly. I know the chemistry for this stuff!

Don, if it doesn't help I will buy you LUNCH the next time we are together (up to 20 bucks).

I do not believe in snake oil or UFO's and I believe that carbon on the backside of the pistons in older engines can create hell.

The front engine runs much cooler than the rear thus more prone to "crap" (carbon).

Skyking, same offer applies.

Bob

[Mark Hislop]

Bob:

If Avblend breaks down the carbon, does one run the chance of getting a slug of carbon right after use. I know this is can happen if an engine has had non-detergent oil, and suddenly changes to detergent oil. Or does Avblend dissolve the carbon?

Mark

[Bob Cook]

Mark

It appears to dissolve the carbon as opposed to "cleaning it in chunks".

It is very expensive for what it is but it does the trick.

BTW there is a real good article

http://www.avweb.com/articles/pelperch/pelp0059.html

worth reading.

bob

[SkyKing]

Sure would be nice if there was a way to respond after each message to that particular individual's comments... SO, sorting through all of this, here's my nickel (hope to keep this somewhat straight forward!):

First, DON: You may indeed have a governor problem if your rear engine won't keep steady with the front, or vice-versa... I do hope you run the friction knob up good and snug, as that does help to keep things steady. But I've noticed it kind of depends on the operating WX environment... I've had days when things just purr along beautifully without having to readjust the props.... and then there are those days when nothing wants to stay synched up. Wonder if when you've experienced the variations in MP if you tried selecting a higher RPM and/or boost pumps?

Second, GMAs & MARK: As to the dissonance (I assume the wow-wow-wow sound), I'm only hearing this occur during the very early part of the takeoff roll... in the climbout, and in cruise, we don't have any of that occurring, like Don is apparently experiencing. When we've experienced the MP/Fuel Flow gyrations, the governor's have held the engine RPM's very close, and again, I think this may be "bootstrapping"... and that's what we're looking into now. Next time out we'll try a higher RPM and see if that cures the MP gyration problem up in the teens. Oh, and no "sagging oil pressure"... all is top green and no oscillations-rock steady.

BTW, I was looking on the type certificate for the TSIO-360C/CB, and it lists "5 useable quarts" in the oil department. Last couple of flights we've used 5.5 and no belly scum... clean as a whistle!

Third, BOB: As to the AvBlend, it's probably good stuff and we might give that a whirl... but another product out there without the "A" word attached has done a magnificent job of cleaning out our front engine and lubricating the upper end... and would you believe it's only about a $1.99 a Quart (32-ounces) from Wal-Mart!!! It's called Rislone... and it's GOOD STUFF! AvBlend is $19.95 for 12-ounces and I see they recommend two-cans for a 6-Cyl engine. BTW, my rear engine runs cooler than the front.

The last oil filter change on the front showed almost no carbon... and before we started using it we saw the oil filter folds full of it and used to see little tiny carbon flecks attached to the leading edges of the white antennas on the belly in the exhaust slipstream... these days they only get coated with a very light tan color -minus the specks and flecks. So that's a good indication. We're changing the the oil & filters at 25-hours, but this last time we did the front engine at 20 hours.

Speaking of aircraft piston-engine oil... I'll bet if we knew the matching MIL number and specs of a good grade of automotive or diesel engine oil - in the same weight and viscosity as the aviation oil - I'm sure you'd find there's not a dime's worth of difference and your engine would run just as well. Of course, that's a well guarded secret by the oil companies. But YES, in that department, we continue to use the single-grade of AeroShell W100-50 year round.

Like a lot of things, the turbochargers are a standard automotive unit... but added to that is the "A" word (Aviation) and the God-like words, "PMA-FAA" approved. Yep, it's true... and a whole bunch of folks are capitalizing on this little deal. Look at your alternators... nothing much different except for the connection to the engine, at least on the TCM TSIO-360's.

Here's a clever trick the oil companies play on we pilots. Ever hear of the term "BRANDED aviation fuel"...? That's where the AvGas comes out of the same storage facility, but gets labeled AirBP, AVFuel, etc. Like up in Seattle, there's only ONE bulk plant for AvGas... it's the Equilon facility on Harbor Island. Equilon is really Shell. But when we get it at our local FBO, it's now "BRANDED" as AvFuel or AirBP. Cute, hey? So then, why the big variation in the end-user price??? Hhhmmm. Another little racket.

SkyKing

[Bob Cook]

Skyking

the "wowing" IMO is either governor or fuel flows may be a bit off. I would at least check them to make sure.
at higher alt I have put on boost to low and readjusted mixture. Seems to settle engine on hot humid days.

re oil. did you not know they "monitor" the oil going into the jugs?

changing oil every 25 hrs is a big +++. AV blend, rislone doesn't matter. Anything to get the carbon down to a managable level including super lean when idle or taxi.

Let's not get onto the FAA/PMA issue! That's a hornet's nest. I am not about to suggest, recommend, or mention anything that is not "approved". Did you read the article on AVWEB (above) ?

Bob

[skymaster]

hEY gmas: screen is from rv automatic transmission. its not a pma part and it came with my aircraft. the previous aircraft owner is pushing daisies. He thought it would be a good idea. James Henderson

[SkyKing]

Yes Bob...

I did read the Pelican Perch article on "Fried Valves"... twas a VERY good read. Thanks for the heads-up! I saved it to CD Rom for later re-reading. Good stuff.

No argument here... 25-hours on the oil is the way! Especially considering the former owner only flew the plane about a half- hour each month and the oil didn't get changed except at annual. And there were a couple of times it sat out-of-annual for two year runs, so that wasn't good either... at least he kept it hangared and in a dry-climate area during the non-use.

I'm sure the bird never experienced my 75% power climbs up into the teens, nor cyl-head temps approaching 380F, and this routine has obviously "unsludged' things.

And DON... NO!, I wouldn't do an overhaul as long as compressions and power are good to go. You've probably got a similar situation to mine... too much setting and sludging. So, change those filters and oil, run it lean and most importantly, make sure you heat the engine up, burn the moisture off the oil and get the gunk out. EXERCISE...EXERCISE...EXERCISE!!!

Mike Swanson is supposed to be up my way in the next couple of weeks and he tells me he's bringing the wastergate-controller "cleaner-outer" purging kit with him, so we'll make a parts list and share with the rest of you turbo operators.

As I'm writing this, just heard a radio commercial that Shell is coming back (the deal is, Shell/Equilon are taking over all the old Texaco outlets as part of the settlement thingee with the merger of Chevron/Texaco... Gee, I hope they bring us some "BRANDED" Shell AvGas too... Maybe we can get the price down below Two Bucks.

BTW Bob, I think I'll try a can of AvBlend and see what gives...

Skyking

[Don Hickman]

Yes, Bob, I read the article on burnt valves. But I didn't find much in the way of legalese in it so most of it probably went right by me. However, taking your advice I'm changing oil tomorrow and putting in some AVblend. Will let you know what happens.

And, Skyking, I'll keep running my hightime front engine until either the compression goes south, the oil consumption goes north or the metal goes up. How's that? Now you just better hope I don't have to use that VERY expensive little rubber dinghy I am required to carry along every time I fly over the Gulf!

While I'm at it, I'm having my mags replaced on the rear engine. Hopefully that will stop the engine roughness I've started experiencing above 16,000 feet. And we're going to clean the screens in the prop governor. Maybe one of these days I'll actually get the thing running right!

[Bob Cook]

Don

What a way to get a free dinner. If you hit me up I want a receipt for that AV stuff <G>.

If you do not have pressurized mags then you better put the mod in or you are going to experience misfiring above 14k ft about 25 hrs after the plugs have been cleaned. It is not that expensive to do. You add a filter and run the upper deck air to the mags thru the filter.

I was experiencing the same thing until I added the pressurization.

Don't even think about the little yellow rubber ducky err dingy.........

How's the dog (not talking about AC)?

Bob

BTW: Southwest have relabeled the autopilot. It is now know as .......... "designated driver"

[kevin]

Just for another viewpoint, my mechanic felt that proper ignition maintenance would prevent high-altitude miss. He did not like the pressurized mag mod, I can't remember why.

Anyway, I clean and gap my plugs every 100 hours, and I have not had problems. I fly at 18 to 20K very frequently.

Now I'll probably get it on the next flight, just for opening my mouth...

I still think Bob's right, and pressurized mags are the way to go.

Kevin

[Bob Cook]

Kevin

It was highly recommended at the CPA course. These mags are smaller than the 400 series and are more prone to have ignition jump within the mag itself. I should not have stated 25 hrs, however, since I did the mod I have not had problems.

It was simple to install and you add small fitting on mag and replace one of the filter with a plug. Suggest it be done when the mag is out or when the rear inside cover is open.

Bob

[kevin]

It seems to me that he was saying that it blew "crap into the mag" (that's mechanic talk). Whatever. I wanted to install them, he balked, so far he has been right, but if I have even a hint of a problem (now that he has retired), in they will go.

Kevin

[Don Hickman]

Same with my mechanic. He took out the rear mags yesterday and one has a shot bearing and the distributor block on the other is bad so that probably accounts for the rough running at altitude. I told him to put in the pressurized ones but he doesn't want to and points out correctly that the front engine runs smoothly at altitude so it's just that these mags needed repairing. Guess we'll see what happens when he reinstalls them.

[SkyKing]

Hi Don,

Curious as to how much time you've got on your rear engine Mags... and the front Mags too.

So far, no mag probs on this end, with our rear reman at 150hrs, and while the front engine has 1250, factory reman mags were installed about 250 hours ago. One counsel tells me they should be R&R at 500 hours, and yet another says they need only to be taken off at 500 hours and sent to a mag-shop for preventive maintenance... what say GMAs?

SkyKing

[Bob Cook]

Skyking
Think there is a mandatory overhaul at 500 hrs on the mags.

the filters on the pressurized mags are clear and there is no sign of oil or dirt showing up so far after 150 hrs.

GMAS

Question. Have you ever seen engine mounts fail on the rear engine ? What is you opinion if two failed on the same side?
BTW nothing to do with my aircraft.

Very interested in hearing from you , or anyone else.

Bob

[Don Hickman]

Oh, Bob is just being nice. He's inquiring because I have two failed mounts on the right side of the rear engine. And, no, I don't bounce my landings! My mechanic said he had never seen engine mounts fail the way mine did. But then he also said he had never seen mags in such bad shape and the engine still ran, either. Just lucky, I guess. The engine mounts failed sufficiently to cause the entire engine to shift to the right such that I could no longer get the oil dipstick out without using a lot of force to push it to the left. So when I got back from Mexico this weekend I told my mechanic about it which is why he went looking to find the failed mounts.

Skyking, the mags had 1200 hours on them. I haven't yet looked through the logs to see when they were last overhauled. But they're getting overhauled now!

My mech said the screens in the prop governor were clear so he thinks the RPM variation on the rear engine that I have been experiencing at cruise may have been caused by the mags. But the interesting part about that is that when I would do the runup and the mag check, the rear was completely steady. No RPM drop on either mag. Go figure!

[Mark Hislop]

Don:

No RPM drop on either side sounds to me like broken P leads. It happened to me, with my factory reman. I think there were wire connectors that were not properly connected in my case.

Mark

[SkyKing]

Don,

I'm beginning to wonder, do you have any recourse back to the selling dealer for the problems you're experiencing, or did you sign away with a forebearance? If memory serves me, I think your plane came from Bar-"X" with new paint, panel and interior... is yours the one with the big letters on the fuselage sides, serial #190?

I've never heard of an engine mount failure... do you think maybe there was some hidden damage from an incident before you bought the plane? Hhmmm.

Mark's right... if you're not getting ANY drop, your P-leads are probably defective... WATCH OUT FOR ANYONE AROUND THE PROPS WHO MIGHT THINK TO MOVE THEM... NOT GOOD!

SkyKing

[Bob Cook]

just turn off the engine with the mag switch. if it doesn't shut down then you have a failed switch or open P lead.

and re mnts.

I have never heard of failed mounts like this / reason for asking Gmas and anyone else. This could also cause the engine WOW. That is scary to have engine mnt failures. I have only seen deteriorated rubbers.


Bob

[kevin]

For what it's worth, we found the actualy engine mount frame (or whatever you call it, i.e. *not* the rubber "mounts" that you change when changing the engine) on my '73 P337 had significant damage due to a cable that came loose and started rubbing on the *inside* of the frame, where the ongoing damage was not obvious. We had to remove the engine, have the frame repaired, and then reinstall. Fun (not).

Kevin

[GMAs]

the mag problem....

Lets see... ya it says that you should have them checked every 100 hrs at annual for points and condition... Hmmmm 1200... now thats a long time for a mag... your mechanic should have picked it up... but, how come YOU don't read your log books,maintance manual... after all you are the one.. that is responsible for your plane...right... (we have been thru this how many times...smile)

As to our recomendations...

normal asp non high flying...

We recomend that you have the mags serviced every 500 hrs... along with the alternator... smile... Now some have said .. well ya we took a look at them and they looked fine... but, my response was ... how do you know if you don't take them out of the plane/engine... which most are not.. they just look at them sitting their... no.. no.. that is not what we mean... the mags come off and go into the shop... and are opened up and and inspected and repaired... the ignition wires are tested with a meggar.. for break down.. etc...

Most of the time they ..the shop.. such as savage mag......

SAVAGE MAGNETO SERVICE PO Box 2401 Airport Station Bldg 73 Oakland Int. Airport
Oakland, CA 94614 Phn: (510) 562-2941 Fax: (510) 562-1593,

will do a tear down and inspection/overhaul... cost is minimal.. but, when done...it is then run on a mach and tested for operation and voltage... as well as crossfireing... which well get to in a min...

their are more things in the mag that can happen wrong than just it makes sparks... timing and springs get out of whack... seals and bearings get dry... so their are a bunch of reasons to have them done at that interval.... as we have found it keeps the fear factor down with the passengers...

But,....

Now for the high flyers.. them TURBO guys...

Here we recomend that you take them out and have them inspected every 250 hrs... yep.. thats not much... but, because you are up in a drier climate way up their things go bad quicker... grease which has water in it... yep it does... drys out...oil oxidies faster...etc... causing drag on the bearings... this in turn causes the impuse spring to have to work harder... etc... seals are another item that seem to dry out faster... and of course the crossfiring in the dist block seems to happen more frequently... which we will get into here in a min...

again the inspection is not just to physically look at the mag.. its to open it up and check how its doing... and replace any parts that are not within limits... or carbon tracked... (Bendix overhaul manual...TCM x42002 and "the Magneto Ignition System" by John Schwaner at Sacramento Sky Ranch... 800-433-3564... are two good books to have... and in Johns' book he has a section on High flying make sure you mention the 337Skymasters Club for the discount)

Now as to the pressurization of the mags... the reason that your mechanic is reluctant to change is becasue if the turbo has problems... and/or starts spitting oil/parts... guess where its going... right into the top of the mag... also it has been shown that the turbo air... you know the stuff that is compressed from the compresser side of the thing... is a lot hotter... yep about 250 deg F... don't believe me... start up and go for a flight.. land and then try and put your hand on the intake tube... its real hot... and its not from the engine... its called heat of compression... on turbines it gets up to about 450 deg f in cases... you can cook with that... and the hot compressor section gets up to about 600... but, that is for the turbine guys.... we are talking our little turbo compressors.. here....

Now if you have a device called a intercooler... then you take the temp of the compressed air for the intake back down to normal air temp levels... but, if not.. well... all that hot air is going inside the mag... and now while its dry air.. which has higher resistance to allowing a spark to cross (oh ya.. think spark plugs too.. and ignition wires... smile)... it does have its drawbacks... the heat.. which cooks parts like greases and seals...

So putting the pressure connection on... well just remember 250 hrs... is your max time for overhaul of the mags... I would think if you don't need them... I wouldn't put them on...

Now... a word about spark plugs and ignition wires...

As you go up... the density of the air decreases...along with mositure... so to make the spark jump the gap in the plug.. is going to require more voltage... yep it goes higher... and if you have a bad wire harness for the ignition... guess what... is going to start jumping out of the wire its in to x fire... to another one that it likes... not firing at the appointed spark plug...it should.... a lot of time it goes to another one that is on the intake side... fuel rich air takes less voltage.... and sparks that plug befor its time ... not good... as it really plays havic with the engine.. but, you don't know it because the prop and the mass motion is greater than the power generated.. but, the engine does...

So you can have a spark plug/ mag/ wire harness that appears perfict down on the ground.. but, up in the air... its a nightmare... and not doing what it should... and no the JPI/EGT doesn't seem to show it...

Ya.. Ya.. so what has this got to do with my broken motor mount... well the stress of the x firing is putting a pulse on the mount... and because it is so repitious it is causing it to flex... and like flexing a piece of bailing wire back and forth so many time... it will break eventually... not to mention what is happening inside to the crankshaft counter weights... which I would have checked too by the way... along with the crank and the prop and hub... as these will be the next things that will start cracking...up... and can actually end up breaking the crank...

so is the maintance of the mags improtant... yep ranks right up their with the fuel... and if you don't do it... well I am sure you all have heard the old saying... you can pays' me now ... or you can pays' me more later ... and here it does make a differance...

If you like we can get into the mags further... as their are several things that you and your mechanic should check for... and we came up with a neet little device to check them... both in flight as well as on the ground... because the impulse springs are another biggie... and most engines don't fire both plugs at the right time...unless you check it out... their are several AD's on the mags we use that don't seem to be complied with... you might want to check it out and make sure your is done too... again.. if their is any interest we can compile a status report that you can check against... along with the AD's and how they are supposed to be complied with... your mechanic should have access to the AD listing.. and it should be posted in the back of your log book... you remember that thing.. its what was supposed to be done to the airplane....

So in closing... this little mini siminar on mags... I suggest that who ever is replacing the motor mounts... (not the rubber stuff)... that you are being given a warning from the engine... something is not right in it... something is either not in time.. or that something was put in wrong... and yes mags can do it... along with bad ignition wires... and now bad counter weights on the crankshaft... as well as bad spark plugs... and one other thing... fuel... valves and lifters... (see that was really 3 things but... just checking...to see if you were paying attention)

checking the log book is the first order.. and using a seperate piece of paper of the computer... put the date, time and maintance or replacement item... and compair it to the current time and problem... (YOU ALL.... should be doing this with yours too... for record keeping... some of the computer gurus might want to come up with a program that others could have to keep records on the computer with.. would be nice)...

you should not be breaking motor mount frames... and if the vibration is so bad that its causing a cable to rub thru... you got a real big problem... that is ringing a really.. really ...big wake up bell... which if not answered.. could cause you to buy the farm... to keep flying it.. is not what you want... to do.. until you can fix the problem... its not normal... and should not be though of as such..... remember I said once the engine does talk to you... well... its limping around...breaking things.... think it has a problem???...

start with the simple things... and work up... but, because it has been going on... its later than you think.. and may end up costing you big bucks.. to have a safe plane... vibrations are deadly... to metal and... to you....

GMAs

[Don Hickman]

P leads were broken. So, when I thought I was turning the mags off I wasn't accomplishing anything. Lesson learned.

Logbook shows that the mags were removed and worked on about 3 years ago which would have been less than 100 hours before I bought the plane given how little it was flown. But my mech says there's no way that any significant work was done on them given the shape they were in. So we're no longer taking the logs at face value and are going to check into everything.

But given the amount of hours I'm putting on the plane (150 in the last 8 months) versus the amount it was previously flown (25 total in the 2 years prior and only about 50/yr for the previous 25 years), I should think that we'll eventually get things working right.

And thanks to GMAS and all the others who have written with info and ideas. I'm saving everything, printing it out and taking it to my mechanic. You guys have all been very helpful.

So, while I'm seeking help, how about someone telling me how to seal the darn avionics compartment? We've tried everything and still it leaks when I fly into rain. The last rain I flew into knocked out my GEM. Now I no longer know my EGTs or TITs or any other temperatures. Sometimes when I fly into rain it knocks out my Shadin fuel flow gauge -- it registers 0 pounds per hour until it dries out.

My mechanic is about at his wits end. Says he's tried everything, sealed every place he can think to seal, put in new silicone gaskets under the access plates in front of the windshield and still it leaks. Not as much as it used to (it would soak my feet!) but still the avionics are getting damp. Hard to do IFR work when you have to stay dry! Any suggestions?

[Mark Hislop]

Don:

Your mechanic probably already has done this, but just in case..

Make sure that all of the little cups under (one underneath each dzus fastener) around the periphery of the avionics inspection hatches are actually there. They are just glued in place, and over time can fall off. If these are missing, water can leak through the fastener.

Mark

[Don Hickman]

Yes, he's checked that before. Still no idea how the water is getting in or from where. And what I can't understand is how water can come into the plane while it's pressurized. Seems to me that if there's a leak, air ought to be going out, not water coming in. And, if fact, I can't get more than 2 lbs cabin pressure differential so there's got to be leaks somewhere. We've replaced all the seals, grommets, etc. where cables, etc. go through the pressure vessel but no difference.

Ah, the joys of Skymaster ownership!

[kevin]

My airplane seemed to be leaking in that area (P337), but it turned out to be the windshield.

Are you sure it is leaking in when you are pressurized? Could it be during climb or descent?

Try it the old fashioned way. Put some cloth or something else that is absorbent inside the avionics bay just under the panels. Put the panels back on. Pour water over the panels (small amount at first). Take panels off. Location of drips should show you where you need to work. If no drips, try more water, eventually spraying seams lightly. If still no drips, this whole process should show you a leak somewhere else, then you can work it.

If you get water on the avionics, obviously work very hard to dry them out before turning things on again.

When I got my airplane, it had been left out in the elements for six months (Oregon, it rains once in a while here). During prepurchase, we discovered it was a water bomber. There was about an inch of standing water in the belly. Drains were blocked. You probably should check this too.

You (and I) are not alone. The only other P337 here at Hillsboro has similar issues when he left his airplane tied down outside. Mine is hangared.

Kevin