The International Cessna 170 Association

I wanted to start a thread and document the overhaul of my engine for fun. 8180A is currently disassembled for a restoration and paint job. I decided it was a great opportunity to overhaul the engine while the plane is down. I have several ideas floating around my head for this engine. We will have to see where it goes. The motor is a C-145-2H with about 2200 hours. It still runs great and hasn't been using much oil. But given the hours and all the other work I am doing to the lane I figured now is the time.

Yesterday we pulled the motor off the nose. Pretty straight forward. The last two motors we did were an O470 and O520 so this seems simple. Just disconnect all the wires and controls and the four engine mount bolts.




Motor mount and carb removed.



Removing accessories...





Rear cover is off. There was quite a bit of wear on the starter gear.

Day 2 and removing the cylinders. Most of the bolts came off ok. Had a couple that were stubborn. Oils pan came off ok too. I will be putting on new Millennium cylinders when this thing goes back together.

Thanks for taking the time to document this process. Can't wait to follow it along.

Jughead

Same here. Great pics. I understand from other posts that there are some important steps or procedures not covered in the overhaul manual. I would be great to document them, along with any other noteworthy or special parts of the overhaul. I'm looking forward to the rest.

Careful with the connecting rods. You might want to make cardboard blanks or stuff rags to prevent the rod from flopping and smacking the case. A nick in a rod make a big stress riser and can make the rod ends part ways later on.

Thanks guys. Normally, the engine would be on the engine stand at this point but we cannot find the 8 hole O-300 flange for the engine stand. We are going to make a new adaptor for it out of some steel plate.

While you're at it, you should slip in a set of chamfered C-85 pistons. No one will know but you and your mechanic

Oh! Yes, I can relate to that. It makes a fine engine especially with superior cylinder assemblies. A lot more bang for your buck figurely speaking .

I got a good afternoon's worth of work today on the motor. We split the case and got our first real good look and the crank and cam. The case came apart really easy. I thought it was in pretty good shape considering how old it is. I might be dating myself but I have never seen copper safety wire lol.

First case half.


Second case half.


The cam shaft looks good. Only minor wear and no pitting. The lifters were is good shape as well with no pitting. So far so good.





Lifters removed.

On to the crank. I am glad my motor has a dampened crank. I was not sure if the C-145-2H had one. The main journals look to be in good shape. We did a quick check with the mic and the crank appears to be a first run crank (never ground). So hopefully there is room to play with assuming everything else checks out. I don't remember the reading off the top of my head. Next the rods come off and the crank gear. The crank and cam are boxed up and will be shipping out to Aircraft Specialties on Monday.

The C-145-2H had a prop control arm near the front of the case that operated a valve inside the oil gally. The oil pressure could then drive a controllable pitch prop. My motor had the control arm safety wired (brass wire ) and someone put silicon caulking over it at some point. Here is a look at the valve for any of you guys that are interested.

Two screws hold the plate onto the case.


A single gasket underneath.


The cam that operates the direction oil can travel.

Just a quick shot of the oil pump.

Do you have the correct crank? Yours should have a snap ring holding a piston behind it. If no snap ring and a welch plug instead of the piston, you have the A model crank which of course is wrong.

Almost all C-145 had dampened cranks. A relatively small number of the first run, those C-145-2 made in '48, did not. There were never any 2H or 0-300 series without dampeners.

Copper safety wire is a break away safety wire still used today in applications where you want one of two things and they usually go together. You want a positive lock that could be broken away by hand in an emergency and or a visual indication the device has not been moved. Such applications are emergency door releases and fire extinguishers. Such wire is usually think like . 020. If memory serves me way way back in the golden age much thicker copper or brass (probably an alloy of both) wire was used.

The bevel on the starter gear is not wear. They are designed that way to aid in engagement. Obviously, as it has been used the teeth will not be pristine.

Glad your cam and followers looked better than mine!

Bruce Fenstermacher wrote:Do you have the correct crank? Yours should have a snap ring holding a piston behind it. If no snap ring and a welch plug instead of the piston, you have the A model crank which of course is wrong.

Almost all C-145 had dampened cranks. A relatively small number of the first run, those C-145-2 made in '48, did not. There were never any 2H or 0-300 series without dampeners.

Hi Bruce, Yes it has the snap ring. That is also good to know about the dampeners. Most of the safety wire on the engine was copper. I am guessing that was all done a looong time ago. I was always told by my grandpa that everything on this engine was original. But since we lost the original logs in a house fire last year I cannot verify that and will never know. 2100 hours TT on the tach so it may be possible. It almost looks to me like it may have been topped at some point because it looks like someone painted some of the parts like the intake manifolds. I am guessing they were not red originally. Also, the paint on the motor looks like green.

Glad your cam and followers looked better than mine!

Wow. Not a good day when you see that!