exhaust

kog · Post by **kog** » Fri Sep 07, 2007 5:53 am

I'm in annual on 3166A and found that I couldn't pull the exhaust shrouds for a pressure check on the exhaust system without a lot of bloody fingers and cursing. This plane is new to me and this first annual is extremely thorough (as one might hope all were). Anyone have a comment on examining the exhaust system by either removing the entire system first or just removing the shroud first? This is an O-300. One other thing; do many of these engines have the propeller governor valve/lever on them, and if they do, any ideas for finding the two gaskets involved?

Fri Sep 07, 2007 12:42 pm

No ideas on the exhaust shrouds except be careful they are sharp.

I would not remove the whole system to inspect it unless you though you wanted to redo, rebuild or replace parts.

As for the prop governor arm. If you have one then you either have the C-145-2H or an 0-300B. If you find you have a 0-300B you might also want to determine what approval was used to mount it. It is not covered in the TCDS or the associations STC even though it is identical to the C-145-2H.

I believe the gaskets and seal come in the overhaul gasket set and so they would be available separately but you would have to order them I'm sure.

iowa · Post by **iowa** » Fri Sep 07, 2007 2:32 pm

mechanics gloves are great for saving skin.
i wear them all the time when working.
i got tired of patients telling me to be careful
and that i was injured worsed then them.
dave

David Bengtson · Post by **David Bengtson** » Mon Sep 10, 2007 3:00 am

Bruce, re approval for mounting the 0-300B engine in the C170. I have seen other questions concerning this on the web site. I can only say that the logs for my plane, a 1956 B model, N3496D, Ser #27039 indicate it was delivered from the factory with the 0-300B engine installed. I can only surmise there must be approval somewhere!

Mon Sep 10, 2007 10:22 am

David I would love to see good copies of your paperwork as well as have that record for the association. If it can be substantiated it could go a long way for others trying to use a B model engine instead of the C-145-2H.

For those unaware David has and is flying his '56 with the McCauley 2 position propeller. A very rare propeller these days and the only one many of us 170 people have ever seen.

doug8082a · Post by **doug8082a** » Mon Sep 10, 2007 11:33 am

And thanks to Bruce there is a photo of it in the 2005 C170 calendar.

I agree with Bruce, getting documentation of that installation would be a real help to the association and some owners out there. Could also pave the way for those who might want to try the Aeromatic prop.

kog · Post by **kog** » Tue Sep 11, 2007 2:13 am

Just got done with annual. O-300B did not show up on approved list but AIP thinks that the "B" notation may not end up being a problem. The O-300B in N3166A is not the original engine. Replace in 1958 as a major repair. Still looking for how it was decided to be an appropriate replacement. We're thinking that the difference in the "B" model is the existence of the oil valve for a constant speed prop. Anyone know if that's correct? Needed garlock seal for it and found NOS one.

Post by **Bruce Fenstermacher** » Tue Sep 11, 2007 9:44 pm

KOG

Some time in the mid 50s Continental changed the naming convention of their engine from the name reflecting the horse power to reflecting the cubic inches of the engine. So a C-145-2 became a 0-300A. The C-145-2H became the 0-300B.

Somewhere along the line 0-300A was added to the TCDS as an approved engine because it was the same engine as the C-145-2. However the 0-300B was never added to the TCDS directly probably an over site.

In those days a lot more common sense was applied and everyone new about the Continental name change and so they recognized the 0-300B as the same as a C-145 2H.

Fast forward to 2007 and less common sense. We know the C-145-2H which is approved for the 170 by the TCDS is the same identical engine as the 0-300B. If you look at the parts manual you will see part for part they are the same engine. They have the same limits and tolerances and operating characteristics and limitations.

If you look at the parts and overhaul manuals you will learn this whole story but unfortunately Continental used the term "similar" to describe the engines. In 1958 the word "similar" meant that the engine could be identical and since people knew that to be the case they were interchanged. Today's cynical world of less common sense, "similar" is look at as being close but not identical. Other wise they would have said "identical" right?

So we are left at this point without a clear way to use a 0-300B on our 170s without converting it to another model or receiving a field approval.

This is why I'm so interested in Davids aircraft information. If he is correct and it can be substantiated we can show that Cessna delivered 170s with 0-300B model engines and so they must be an approved engine and the model information being missing on the TCDS just an over site. Maybe this might lead to that engine being added to the TCDS or perhaps at the least maybe the association can have the 0-300B model added to their STC with the 0-300C and D model engines.

The above information is of course how I see it after studying the details of the C-145-2 and 0-300 series manuals and the TCDS.

kog · Post by **kog** » Wed Sep 12, 2007 12:30 am

Thanks Bruce. I'll forward this info to my mechanics and we'll chat it up. The idea that it is an oversight was our consensus and your explanation fits with it exactly. I too would like to find out more of what David finds in his search. Thanks again.

Post by **GAHorn** » Thu Sep 13, 2007 3:17 am

I'm afraid it's a bit more complicated than that. A C-145-2H is not identical to a O-300-B. They are similar. Not identical. (Just like a
C-145-2 is not identical to a O-300-A.... several differences. Minor, but different. Things like cast iron cam and steel lifter bodies versus steel cam and cast iron lifter bodies ... way too many others to conveniently list.)
The O-300-B was not likely "overlooked'... in my opinion it was probably deliberately left out because by then it was discovered the adjustable pitch prop was not a popular item (due to cost/complexity) and no money was budgeted to continue expensive certification/documentation on minor/unpopular variations.
Even though an airworthiness certificate may have been issued with the unapproved engine installed.... that does not make it a legal installation. It makes it an undocumented modification that a subsequent inspector may suspend approval on. (The FAA always has the option to revoke airworthiness certificates that were inadvertently/inappropriately issued. That's why I went to the trouble to obtain proper approval for my O-300-C installation the FAA improperly issued an airworthiness certificate on.)

I recommend you obtain approval for the engine installation, either by field approval or STC if possible. Otherwise you risk finding your airplane's certificate revoked at an inopportune time or location. (No telling what a savvy insurance guy might do after the fact.)

Joe Moilanen · Post by **Joe Moilanen** » Thu Sep 13, 2007 5:09 am

gahorn wrote:I'm afraid it's a bit more complicated than that. A C-145-2H is not identical to a O-300-B. They are similar. Not identical. (Just like a
C-145-2 is not identical to a O-300-A.... several differences. Minor, but different. Things like cast iron cam and steel lifter bodies versus steel cam and cast iron lifter bodies ... way too many others to conveniently list.)
The O-300-B was not likely "overlooked'... in my opinion it was probably deliberately left out because by then it was discovered the adjustable pitch prop was not a popular item (due to cost/complexity) and no money was budgeted to continue expensive certification/documentation on minor/unpopular variations.
Even though an airworthiness certificate may have been issued with the unapproved engine installed.... that does not make it a legal installation. It makes it an undocumented modification that a subsequent inspector may suspend approval on. (The FAA always has the option to revoke airworthiness certificates that were inadvertently/inappropriately issued. That's why I went to the trouble to obtain proper approval for my O-300-C installation the FAA improperly issued an airworthiness certificate on.)
I recommend you obtain approval for the engine installation, either by field approval or STC if possible. Otherwise you risk finding your airplane's certificate revoked at an inopportune time or location. (No telling what a savvy insurance guy might do after the fact.)

Another alternative is to fly it and be happy. If you can find an IA to sign it off, live your life to the fullest.

dilligaf!!!!

ron74887 · Post by **ron74887** » Thu Sep 13, 2007 2:18 pm

Buy the book, They are not identical, however the O-300-a is to the c145 as the B is to the 2H. just like the E is to the O-300-D. The A was certified in may 54 and the B in sept 55, maybe not enouh time to add it to the 170 but it was added to the 172, so that the prop is not the reasons. Similiar in the type cert does not mean identical but all parts are usable in all engines. If not you would be hard pressed to find used lifter bodies, cams and the other slighty different materials and not be able to use them. as Continental states they will not warrany it (big deal) but you can use any crank or cam in any case. they are identical in operating limits and in the type cert "--" means same as preceding model ,meaing they were the same as the 145 and all O-300 have that designation. Trying to get the B approved as we are discussing this.

Ron

Post by **Bruce Fenstermacher** » Thu Sep 13, 2007 2:32 pm

Ron and I have been discussing this privately. I requested that Ron, the originator of the associations engine STC, contact the FAA and inquire about adding the 0-300B to our STC. He has made that initial contact and the inspector he spoke with is looking into it. It is to early to say if this will or will not get done.

Dave · Post by **Dave** » Thu Sep 13, 2007 5:29 pm

Hi Bruce
I ran into this a couple of years ago with a 56' 170B model I was doing a pre-purchase inspection on in Langley, BC. I spotted the prop control on the left front engine case right away, indicating an 0-300B, and the lever lockwired in place. I had heard of this before. The engine had been overhauled not too long before and identified as an 0-300A. I had to fax over the pages from the Continental Parts Manual (shows it all quite plainly) before anyone would believe me.
I may have some records still from this aircraft so will have a look.
Cheers
Dave

blueldr · Post by **blueldr** » Thu Sep 13, 2007 6:53 pm

George,
Your recommendation stopped short of a solution in the event a "one time" or STC was unavailable.
What would you personally do? Buy a new engine? Junk the whole thing?
I, personally, think Joe Moilanen has the right idea. Life is far too short to let that problem drag on.
I've seen other C-170s with that engine and I've never heard of anyone having a problem.

The International Cessna 170 Association

exhaust

exhaust

0-300B Eng in 170

O-300B

O300B

0-300B