Metal in Filter--Solved

[Mark Hislop]

I tried to post this message in the UNO, but now that it's gone, I thought I would repost here.

Thanks to GMAS' help, we looked at the bevel gears in the drive accessory case. They were in fact undercutting, and this was the source of the ferrous metal found in the oil filter. We checked the inlet screen at the prop governor, and one rod cap (one cylinder had to be pulled off anyway due to a worn valve guide) and could not find any evidence of metal particles circulating through the engine.

So I have to replace the gears, but that is a whole lot better than the overhaul the mechanic recommended.

Thanks to GMAS for his knowledge and willingness to share it.

Mark

[jhickam]

Mark,

There is a company that makes a conversion to do away with the two bevel gears thart run the vacum pump. I have ordered one for my rear engine and I expected it to arrive this week. My mechanic reccomended the coversion because of the ongoing problem with the gears and the cost. By the way it is even approved by the FAA.

Jim

[Mark Hislop]

Jim:

Can you give me any more information on this conversion...where can I get it, how much is it, etc. This would be a great time for me to make it.

Thanks

Mark

[jhickam]

Mark,

Here is the web site http://www.niagaraairparts.com hope this helps.

Jim

[Bob Cook]

To all

This is a friend of mine and the office is at IAG in Niagra Falls. IT is a Canadian Company.

I will try and dig more info on it and see if I can't get some better pricing for those interested.

regards

Bob

[Mark Hislop]

This is an update on the information about the STC'd replacement for the accessory drive bevel gears. After getting the information from Jim Hickman, I contacted Niagra Air Parts. They were just getting FAA approval for their fix for the bevel gear problem.

Their fix is to replace the "TEE" drive gear box with a straight drive gear box. The "TEE" drive allows the installation of two accessories (usually the vacuum pump and a hydraulic gear pump, or the vacuum pump and an airconditioning compressor) to be mounted at right angles to the centerline of the engine. The straight drive accessory case allows only one accessory, mounted in line with the centerline of the engine. If you don't have two accessories (I onoly had the vacuum pump on my engine), the straight drive case will work. This is the same arrangement as on the TSIO-360's used on the Seneca.

While the straight drive is standard Continental design, it is not part of the Type Certificate for the Skymaster. This is why Niagra Air Parts is getting the FAA approval as an STC for the substitution. (I understand they have it now.)

UNFORTUNATELY, this fix wouldn't work on the front engine of my 73 P337. There was not enough room behind the starter adapter to mount the vacuum pump. The engine is too close to the firewall to allow enough clearance to add or remove the pump. I assume this is not the case in other models, but I don't know for sure. I also don't know if this fix would fit in the rear engine compartment.

The replacement bevel gears are about $400 EACH. It sure would have been nice to get rid of them.

Mark

[GMAs]

yes you can change the starter drive to the streight one... and they don't have to have the STC approved by the manufacture of the aircraft...

If in fact you will go to the engine manufactures TC's you will find that they can have either the streight drive or the T drive.

We have replace several of the T drives on the planes which only have the vacuum pump... and yes they will just fit on the fwd and with room to spare on the rear... to change the vacuum pump though it is more difficult because the bottom nuts and washeres are right over the alternator... and you run the aligator pit if you drop one into the alternator... again use the sheld anytime you work on mags or starter parts.. to keep them from getting inside...

If you look at the H model/series engine you will see cont engine used the streight drives on both the engines provided to cessna... so you don't need a STC or approval... just a change of parts from one to the other

Their are two types however...Starter adapters assembly... the older style which will fit the A, D, H,J and K engines... cont engine P/n 627993

and the Newer style Starter adapters/assembly which will fit the A, D, H,J,K and ES engines... cont engine p/n 649988

Now will they fit the other C and G engines... yes... and they are approved... yes... but, they are application ...used... so you might find a older style may not fit... while the newer one will... it has to do with the starter shaft lenght and bushing size... and the mounting ....

Now finding one new... or used... is like looking for hens teeth... they are out their but, everyone else knows their their also and are looking...

If you call cont. engine and give them your engine s/n... they will tell you which one will fit your engine...

Again you don't have to have FAA approval.. the manufacture has the TCDS for either one... thus you don't need a 337 or TC... its already done...and if you don't need the angle drive for other things... like second alternator or Airconditioning... then it might be for you... but, it is expensive... however it does do away with a couple of parts that are not really needed...

Hope this helps... GMAs