for... Skyking... - Page 2

GMAs · #16 08-07-02, 01:14 PM

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 · #17 08-08-02, 12:48 PM

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 · #18 08-08-02, 03:59 PM

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 · #19 08-08-02, 09:08 PM

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 · #20 08-08-02, 10:28 PM

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 · #21 08-08-02, 10:55 PM

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 · #22 08-09-02, 03:32 AM

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 · #23 08-09-02, 07:59 AM

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 · #24 08-09-02, 05:33 PM

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 · #25 08-09-02, 05:44 PM

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

SkyKing · #26 08-12-02, 02:13 PM

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 · #27 08-12-02, 02:30 PM

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 · #28 08-12-02, 09:59 PM

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 · #29 08-13-02, 12:19 AM

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 · #30 08-13-02, 04:37 PM

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