Engine Overhaul woes

[photosfromabove]

So when I had my engine overhauled I changed the oil at 5 hours then again 10 hours later then after 15 hours. Any chance no oil was put in your engine at your last oil change?I have seen this happen at our airport.

 

[SuperCub MD]

Steel rings in steel barrels? Or Chrome rings in chrome barrels? I've seen this before, that would be my first guess.

From the pictures there was a lot of hard steel or chrome particles circulating in the oil system, some are now imbedded in the piston skirts and main bearings. Oil samples measure PPM which is useless in this case. Identify the hard metal particles and figure out where they came from.

 

[nanook]

Oil samples are used to establish a time line....

 

[Steve Pierce]

Travis was changing oil in a Pacer yesterday and found a lot of magnetic whiskers in the oil screen. After he pulled two cylinders on one side he found this flattened cam lobe and several pitted lifters. 1300 plus hours.

 

[Scouter]

Steve was this a bird you maintained? I was curious about oil brand and if CamGuard was used

Jim

 

[SuperCub MD]

Want to make sure I'm getting the right point across.....

Had a plane come into the shop that was acting just like this one after having a new set of cylinders installed. Tore it down and it showed the same wear. The cylinders were purchased from a large supplier (won't say who, this was a long time ago and I know a lot of you guys still deal with this company) who had shipped them with new pistons and rings fitted. The mechanic installed them without checking the part numbers..... The wrong type of rings were fitted for the barrel surface. The installing mechanic and cylinder supplier felt real bad about the mistake, I'm not sure what they did for the owner but I ended up doing a full major OH do to the damage all the metal in the oil had caused.

So check those rings. Make sure someone didn't reach in the wrong parts bin, or the rings may be miss marked or have a hardness problem.

Also, the solid flange crank is a modern replacement for what was originally there. So it has been replaced at some point but it's nothing to get worked up over.

And also, the oil analasis will only show normal wear in PPM. I sent in a sample with chunks and flakes of metal in it you could see and feel. It came back normal...

 

[Helmetfire]

Update on my engine.

Well I decided to do the right thing and send my engine to Ly-Con for the repairs. Originally it started out as an IRAN for metal contamination, but apparently they had sympathy for me and basically ended up calling it an overhaul for about the same price. VERY happy with the way Ly-Con worked with me and my crappy situation, they will be getting my business again (just hopefully not too soon :lol

The cylinders went to ECI for warranty repair, but were denied because they determined whatever FOD went through the cylinder(s), did not com from the cylinders. Luckily all four were able to be cleaned up with honing, so I saved a little there.

Upon inspecting the engine they found a number of discrepancies that needed addressing. The main one being two rods that were red tagged because they had been ground on by somebody. Since they were overhauled prior to installation, my guess is the previous builder was trying to get the weights even by sanding off the casting "bumps". Doubt they would have been sent out from the machine shop in that condition, but I'm gonna make sure. So he basically modified and installed two un-airworthy rods, and the weights didnt even match...which might have been where all the vibrations were coming from.

The oil sump had cracks in a number of places, two of those places weren't repairable, so that was red tagged too. Ly-Con gave me an overhauled sump for a screamin deal.

When the other guy disassembled the engine, he failed to mark the cam followers, necessitating another overhaul of those.

Crank had one journal that was at service limit, so it was re-ground ten under and used oversize bearings. That was most likely the cause of the low-ish oil pressure right off the bat.

various other parts were replaced adding up another $1600 or so.

I opted to have the cylinders ported polished and flow matched, with alodined heads, and the test cell/dyno run after the engine was finished. The engine (with straight exhaust stacks) measured 170 horsepower at 2700 rpm.

Ive got seven hours on it now, and so far it runs great!! Just changed the oil and only found trace amounts of "stuff" on the oil screen, MUCH cleaner than the last overhaul. The engine only burned 1 quart in that seven hours and wasn't that dirty.

Other than ending up with a great engine, the other positive to this story, is that while it was down for 3-1/2 months, I made a TON of improvements to the airplane including all new wiring, instrument panel and some interior improvements. Also added a lightweight baffle mounted oil cooler, and a B&C alternator. After all that work I ended up losing weight...she now weighs in at 1116 lbs. (actual, not paper)

Here's a pic of the rods...

This is what they SHOULD look like...

Installing the engine almost ready for the cowling..

on the test cell at Ly-Con...

 

[Bill Rusk]

Awesome. Congratulations

Bill

 

[T.J.]

I gotta disagree with the rods being unairworthy because the web was ground on. That's how Lycoming used to balance their rods. I've got two rods at the hanger that I just removed from an 0-320 A2B. This is a first overhaul since new. Two of the rods have the webs ground. I know it was done by the factory because the P/N is stamped on top of the grind area. I'll get pics tomorrow.
Question? How does Lycon balance their rods?

 

[Alaska_Rallyer]

Im pretty sure they just go through their collection of rods until they find some that match in weight...

 

[nanook]

Agree with TJ. I have seen factory rods with material removed. The airworthiness criteria is obviously cracks, twist, stretch, and ends dimensionally. An overly heavy rod would have material removed for balancing.

 

[sierra bravo]

The photo of the rejected rods indicate the beams have been ground. I've had rods balance matched and they've never been ground there. The link technique is consistent with what my rods looked like post-balance.
http://www.youtube.com/watch?v=QLpiF0E0EJU

 

[Steve Pierce]

I have never seen one ground like that. Looks like someone used a die grinder. The only thing I have seen is the seam where they were cast cleaned up.

 

[Cub junkie]

Obviously not an accetable practice in certified aircraft engine rebuilding according to the red tags but smoothing down the forging seam on a connecting rod is common in auto racing. That was one way it was done until affordable(i.e. made in china) racing parts were available for the saturday night racers. The pictured rods don't look like very good workmanship was used in the sanding process.

 

[T.J.]

This is grind marks on a 0-320 out of a first time overhaul engine. There is two rods with grind marks.

 

[beezerboy]

glad you got a good fix. I'm another that suspects cleaning media in the oil galleys as part of the problem. the 320 narrow deck is known to hide media even when a super cleanup is done. there were other problems though, that aren't directly related to that.... one is the oil control ring. pretty hard to do damage to that one by running it. on the other hand it is pretty easy to screw up installing it. also, I don't see how you can damage the bottom ring with fod and not damage the 2 above it. I topped a VO435 years ago that had bad rings. the top rings & lands in a couple cylinders were broken.... and pieces were missing, etc.... EVERY cylinder had pock marks on the piston heads. I called Lycoming & the rep said, yea, the cylinders swap spit & the pieces migrate around... go figger. (same reason for Gami injectors). interesting thing was the owner spotted the pits on a piston dome during a plug change & that started the investigation. all the cylinders made compression even with a couple broken top rings.

for the vibration, my first guess would have been an oversize jug & piston on one hole,,,, but I guess that wasn't it, but I've seen it done. and... a dry tappet clearance check? the clearance has to be checked & fall between .028 and .080 or the lifters won't operate correctly. that can make an engine run rough.

as for ECI... about 15 years ago I put a set of Cermichrome cylinders on my friends cub. less than 2 years later & 200 hours or so all cylinders were failing the compression test. we called ECI, they said, "yeah, we had some bad ring/wall combinations that wear fast". "what you going to do about it?" ... the answer was "nothing". so screw them

sorry, but I need to look in the hole before I install a piston/cylinder. the mechanic is the final quality control, it's my license... not theirs.

and finally.... for others, if you have a problem like this.... document everything, and before it spirals out of control get a disinterested 3rd party to check, confirm, monitor, etc.