Crack in cam follower/lifter housing

[Chrisgoesflying]

I recently noticed a power reduction on my 1946 Ercoupe. Since my annual inspection was almost due, I just brought it into the shop a little early. Here are the findings during the trouble shooting.

I noted lack of power during take off. This was confirmed on inspection and ground runs by the AME. Mags were the first suspect due to age and condition. Serviceable mags were installed. Same ground run results persisted. Fuel system defects were considered and investigated. No abnormal defects were noted. The next troubleshooting step was to check for either a stuck valve or a bad lifter. All valve covers were removed, the prop turned over by hand and all valves were observed to open and close normally. Next each cylinder was placed in the TDC of the compression stroke to check valve clearances and the condition of lifter oil retention. The #1 exhaust was the only one to depress fully by hand. The cylinder was then removed for investigation. It was found that the top portion of the lifter was somehow displaced and no longer in the lifter housing nor was it retained between the push rod and lifter itself. The lifter was removed and the cam follower/lifter housing was found to be cracked approximately .750”. Below are some photos.

What do you guys think is the most economical way to fix this? The engine is a C-85 12F with 1,300 hrs SMOH. However, everything on the top part of the engine is pretty much new. New cylinders, new mags, new starter, etc. My AME said the only way to replace the cracked part is by opening up the crankcase, which is expen$ive! The other option would be to find a decent low or mid time bottom end of a C-85 and swap it out. Do you have any other ideas?

Also, what do you think could have caused this? I bought the plane in March and flew it about 50 hours since, with no issues. The week before I noticed the power reduction, the one hour flight was very uneventful with the one exception of a bad shimmy during the landing roll. Then a week later, I do my run up with no issues, line up, apply full power and only get 2,100ish rpm on the roll when I should be at 2,400 rpm.

Here are the images: https://imgur.com/a/achYCHO

 

[bnt83]

Disassemble the engine and replace that cam follower.

there should be snap rings that will prevent the pushrod socket from falling out of the cam follower.

 

[NavAir]

Looks like you could use some new motor mounts while the engine is off...

 

[Tom-D]

The valve stuck open some time in the past, when that happened the lifter was forced open damaging the lifter.
This is not common, but it happens.
AT 1200 hours I'd overhaul it.

 

[Tom-D]

Disassemble the engine and replace that cam follower.

there should be snap rings that will prevent the pushrod socket from falling out of the cam follower.

early lifters don't have a clip to retain the guts of the hydraulic unit. ( C-65-58) unless they were replaced during previously.

 

[Tom-D]

I recently noticed a power reduction on my 1946 Ercoupe.

your cam/fifter was damaged, you must disassemble the case to repair.
you might as well upgrade to the 0-200 it will be difficult to find parts for the C-85.

 

[Chrisgoesflying]

Thank you for the hints here. We decided to open it up next week and see if there is anything wrong inside the engine. If not, we just replace the one part and put it back together since the engine was running well prior to this. I was considering upgrading to C-90 or replace the bottom part with a lower time C-85 but my AME seems confident enough about the engine itself especially since he's been maintaining my aircraft for many years, even before I even owned the plane. Getting another mid time C-85 or C-90, who knows what hides inside.

Engine mounts: For sure, they're due. Looking for serviceable Ercoupe engine mounts. If anyone has leads on that, feel free to send them over to me. New ones are rather pricey.