C-145 Crankshaft Question

[mekstrand]

So I'm thinking I may overhaul my C-145 this winter. The engine only has 500 smoh, but it’s been a long time since it's been apart. My aircraft has an early (1948) C-145-2. Based on the fact that I have the .25" hole in the flange and no "D" suffix on my serial number I’m assuming I have a non-Dampened Crankshaft. I'm wondering what all you experts think about overhauling an engine with a non-dampened crankshaft (assuming my crank is within limits)? Would it be worth the effort (and expense) to track down and purchase a dampened C-145 or O-300A Crank?

My airplane is operated VFR for fun with modern radios. The 25 amp generator I have is more than adequate.

Thanks,

Marshall

[Bruce Fenstermacher]

NO. You don't need a dampened crank if yours if good. It would be money, lot of money spent for nothing. I had no problem rebuilding my C-145 with an undampend crank a few years back. You can't tell the difference flying either crank and about the only limit I can think of you already mentioned isn't an issue and that is the 25 amp generator limit.

[53B]

Hi,

I overhauled my O-300A this past winter and used a crankshaft from a C145-2 as they are the same part number. However, it has the 1/4 inch hole in the flange but most definitely has the counterweights. I would not assume that yours is undampened based on that hole in the flange just as I would not assume that mine is an original C145-2 crank as I do not have the earliest logbooks. I would agree with Bruce and use what you have if it's good.

[Mark Harwood]

Marshall
I had the same concern a few years back at overhaul. After asking those in the know, I used the undampened crank and am happy I did. The 8 bolt cranks are pricey if you can find one. I may have gone the "D" route if my crank had not been good. Hope this helps! Mark

[davevramp]

How do you put a o-300d crankshaft in a c-145? Is there a STC, SB or any other way to do it?
thanks
dave

[Bruce Fenstermacher]

Dave what you would be doing is converting your A model to a C model using TCM M75-6R1 which we have in the maintenance library. Of course if you also change the accessory case and starter to the D model then you would be converting your A to a D model.

In either case your would them buy the Associations STC to allow the installation of your C or D engine and the appropriate propellor on your 170.

Now if you have a C-145 rather than a 0-300-A then the path is the same BUT not quite in black and white. You see the SB doesn't mention C-145s or 0-300 specifically but instead talks about converting engines of the same FAMILY from one dash number to another. My opinion is the C-145 and the 0-300 are the same and the same family. It just about says that in the parts and overhaul manuals. In fact besides reported minor casting differences they are the same and use all the same parts and have the same limitations. I believe that when Continental changed their engine naming convention they considered all C-145s to cease to exist and instead they were a 0-300. In any case the same family.

It is just logical. But as you and I know logical isn't always found in the FAA vocabulary.

[Brad Brady]

Well here is a good place for me to ask about the O-360 Crank. I think it was two years ago, I believe Del mentioned that the 360 crank would work in the O-300.....Any new knowledge on that idea?

[Bruce Fenstermacher]

I recently talked to Don Swards of Don's Dream Machines. Don is an A&P IA, DME, DAR and is the person who was granted the STC to install the 0-200 crank in the C-85. He is a walking talking small Continental engine man and that is his primary focus it would seem. How ever he is also very familiar with larger Continental engines because he is after all an engine man and they are all so similar.

Since I have his STC and running a 0-200 crank in my C-85 powered Clipped Wing Cub Don spent about fifteen minutes with me talking engines and propellors. In our conversation for some reason the C-145/0-300 crank came up and without hesitation he said you use the 0-360 crank for that. I of course nodded like I was an expert on what he was talking about and that was all that was said

So while that is no concrete evidence or proof to add to the fact that Richard Pulley is already running a 0-360 crank, it tells me that a well respected engine rebuilder would expect to use it if called upon to rebuild a C-145/0-300.

BTW on another subject. Don confirmed that he is able to rebush the oil pump area of the accessory case to usable tolerance on all the small Continental engines to include the C-145/0300. I took this to mean not only the area the pump gear shafts run in but the area the gears run in as well.

[Brad Brady]

Bruce,
This is all interesting and exciting news. I had no idea that Richard had a 360 crank in his O-300. Sounds like the right thing to do to me. Having an engine man on your side is good news also! Hope that things can move forward in this perspective. Finding things that are still in production, (or just out) that is usable for our old engines is a good thing!

[Bruce Fenstermacher]

Brad, Richard has document on here his trouble with the welch plug that must be installed in the front of the 0-360 crank in order to use it in the 0-300.
http://www.cessna170.org/forums/viewtop ... ilit=crank
http://www.cessna170.org/forums/viewtop ... ilit=crank

It would appear from Richard's comments that Continental is selling the 0-360 crank as a 0-300 replacement crank and so they must have superceded the part number for the 0-300 crank to the 0-360 part number which is the path of legality for the engine but not necessarily the airframe which is were the Association STC comes into play.

[N4200V]

I am in the process of doing a full restoration on my C-170. My engine is a mid-time O300D. When I pulled the engine I noted that I was running a 8 bolt flange. My understanding is that the original flange for this engine is a 6 bolt. In my logbook it states that back in 1971 the crank was replaced with a serviceable crank. My question is, is it legal to continue running this engine with this crank where I know it is not an original? I cannot find a 337 in my records for this application. Is there anything I need to do, and will I have trouble getting it signed off when I complete my restoration?

[GAHorn]

Ann, does your engine also have the accy case for the angle-starter and vacuum pump? (If so...the engine is still a modified O-300-D which needs further documentation for the crank/prop change. If not, it's likely been converted to another model, perhaps a O-300-A, per the TCM M75-6R1 service letter.)

It sounds as if your situation is like many others... it's not exactly an "airworthiness" problem...as much as it's a documentation issue.

[N4200V]

Thanks, I will try and see if there was any documentation filled through Continental back when the change was made. According to the serial number it is in fact a D model. Greg

[Bruce Fenstermacher]

I would be surprised Continental would know anything about the change in crank.

What George was getting at is this. Did someone change the engine designation to an A from a D which is legal using the TCM M75-6R1 service letter. Or did they repair a D using an early crank.

If the paper says it was converted to an A then the serial number should have been stamped with a C then an A after the D according to M75-6R1. If this is the case and the engine has the angle starter then then that and a vacuum pump if installed would also have to be documented because they were not available on the A model.

Here is another question. Does this airplane have any approval to install a 0-300-D engine? This is not a legal engine under the TCDS alone. The Associations STC SA7441SW might help in this regard in allowing the -D engine on the airframe but sine you have the early crank you can't run the props spelled out in the STC. Lots of folk would say "so what the prop is approved in the TCDS". And they'd be right and wrong. The 8 bolt prop in the TCDS is approved for use on a C-145/0-300-A not a -D model.

If you think this won't be questioned by the Feds let me tell you about a recent inquiry about our STC along the same lines. A fellow bought our STC and installed a -D engine but he wanted to run the standard stock skull cap spinner. Well guess what. Our STC does not specify the skull cap spinner as an approved spinner and it was being questioned by the local FSDO. I was contacted by the Associations FSDO because they are in charge of our STC. The Fed said that she felt sure the skull cap was approved but need to see our paperwork. (the Feds didn't have a copy ).

I explained that the STC didn't specify the skull cap because change on engines did preclude someone from it's installation like the propellor bolt pattern would. I have not heard back what the final determination was. Guess I need to follow up on that.

Sooooo. It may be easier to convert the engine to a -A throgh M75-6R1 and either remove the angle starter and vacuum if it has one or have that change documented. This way there is a clear legal way to install the engine on the airframe, propeller and spinner on the airframe (via the TCDS)

BTW if you are going to get rid of the angle starter, now is the time with the engine split because the angle starter and the straight starter use a different pinion which requires the case halves to be split to install.

[blueldr]

I'd be almost willing to bet that the guy who had the skull cap spinner problem asked someone if it was OK. I don't ever recall seeing any sort of permission entry in a log book for a bullet spinner on a "52 model, and almost all of them have a bullet at this stage of their life.