My engine fell out

charlie said:
Save the parts when it comes apart so you can see what bearing sets, rod bolts etc to order. Connecting rods may need to be modified to accept available parts. A current parts book will not show the old parts in that engine. The crankshaft probably has sludge tubes installed etc. I've seen older engines like this assembled with incorrect parts. Charlie Melot Xowner Zephyr Engines
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I think that’s Charlie’s way of saying, “Well you broke what didn’t need fixing, now don’t break it even worse putting it back together!” :)
 
charlie said:
Save the parts when it comes apart so you can see what bearing sets, rod bolts etc to order. Connecting rods may need to be modified to accept available parts. A current parts book will not show the old parts in that engine. The crankshaft probably has sludge tubes installed etc. I've seen older engines like this assembled with incorrect parts. Charlie Melot Xowner Zephyr Engines
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I think that’s Charlie’s way of saying, “Well you broke what didn’t need fixing, now don’t break it even worse putting it back together!” :)
 
Just about done. Camshaft has issues. I made the right choice. I'll post some pics when I get some time.
 
The engine looks to be in pretty good shape overall. Interestingly, the top end has been overhauled, but it has some pretty major issues. 3 of the 4 cylinders have broken rings, in one case it's a real mess. The valves don't look to be bad. I haven't removed the rocker covers yet to see how it looks, I will likely buy new cylinders now that I see the situation.

On the bottom end, The intake followers on cylinder 1 and 2 were both badly pitted, and the cam is really munched on that lobe. The crank shaft and all bearings have no issues from a naked eye perspective, and the accessory drive train gears look pretty darn good for 52 years. I haven't disassembled the oil pump yet, so not sure about that one.

Before disassembly
2017-11-10 11.20.57.JPG

Piston #4 is toasted
2017-11-10 12.12.19.JPG

Broken ring from #4
2017-11-10 12.12.23.JPG


The intake for cylinder 1 and exhaust for cylinder 2 were both corroded and pitted badly. They share the same lobe in the camshaft picture that is badly worn.
P1015603.JPG

The rods and associated bearings look to be in good shape
P1015627.JPG


This is what all but one of the lobes look like
P1015633.JPG


This is the lobe that was driving the pitted followers.....P1015632.JPG


cleaned up crankshaft
P1015642.JPG
 
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Seems like it wasn’t all that healthy. I’m surprised there weren’t warning signs of problems with the stuff you showed in the last post, or was your mechanic just ignoring them?

Looks like you’re into it for at least a new cam and lifters. Hopefully the machine shop doesn’t reject too many of your steel parts due to corrosion or else it might get expensive pretty quick. Cranks aren’t cheap if you end up needing one.
 
mondtster said:
Seems like it wasn’t all that healthy. I’m surprised there weren’t warning signs of problems with the stuff you showed in the last post, or was your mechanic just ignoring them?

Looks like you’re into it for at least a new cam and lifters. Hopefully the machine shop doesn’t reject too many of your steel parts due to corrosion or else it might get expensive pretty quick. Cranks aren’t cheap if you end up needing one.
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I'm rather shocked about the ring issues. Compression was good last annual, and I was only burning about a quart every 5 hours. I did grab an oil sample to send for analysis, I'm curious if any of these issues cropped up since my last oil change.

I was planning on replacing the cam in any case, so no heartburn there.
 
Sounds like you made the right call to overhaul! I had similar issues last year with my A65. My cam lobes were ok, but the lifters were pitted, and I ended up replacing all eight, at a cost of nearly 1amu! What really hurt was that all four cylinders were shot and could not be overhauled. I finally located an as-new set of four. Every supplier was out of stock for new cylinders, which is just as well, as a set of four with valves is $4800. Your replacement parts should be easier to find, and hopefully less expensive. Keep us posted with updates. I'm curious as to what might have caused the rings to break like that.
 
Salty said:
I'm rather shocked about the ring issues. Compression was good last annual, and I was only burning about a quart every 5 hours. I did grab an oil sample to send for analysis, I'm curious if any of these issues cropped up since my last oil change.

I was planning on replacing the cam in any case, so no heartburn there.
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Same plan here, new cam, lifters and hydraulic units.
 
charlie said:
Save the parts when it comes apart so you can see what bearing sets, rod bolts etc to order. Connecting rods may need to be modified to accept available parts. A current parts book will not show the old parts in that engine. The crankshaft probably has sludge tubes installed etc. I've seen older engines like this assembled with incorrect parts. Charlie Melot Xowner Zephyr Engines
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Hi Charlie! Haven't heard from you in ages! What have you been up to? oh wait - sorry - no thread hijacking this early in the morning - starting a new one.
 
It's amazing that engine was running good. It shows how tough they are.
 
I’m surprised at the ring damage.

Think the prop strike was handled incorrectly or they were installed wrong back then?

Was going to ask if you do oil samples regularly or have a baseline for them? I would think that much metal working it’s way loose would have shown up there, if not in the filter. I assume you cut open filters and look and use a magnet, etc.

Our news back from Annual this year is that we’re at 1269 SMOH Which was done in 1992.

Haven’t seen a compression below the low 70s ever, and log review shows the same.

We have the supposedly “undesirable” chrome cylinders popular in the late 80s/early 90s, but there seems to be one good use for those, and that’s airplanes that sometimes sit for a while and don’t fly enough.

Ours has had a few years like that obviously with only that many hours since ‘92. That’s only a 50 hour a year average and we fly it more than that. So it sat too much in the past.

(TTAF is only 2939 on a 1975. 69/yr average over 42 years.)

Chrome plus our incredibly dry climate may have actually helped this engine be happy for this long.

Plus we seem to be just before the rash of bad metallurgy in cylinders era started.

(I believe chrome is correct. Orange paint band, right? Doesn’t matter. Whatever they are they’re not going anywhere. Ha.)

So, we keep watching and waiting for any tell-tale signs of problems. Knock on aluminum and steel.
 
Cylinder 4 with the major issues was chrome with the orange paint. It was replaced in 94 when compression was 30 - top ring was broken.

I'm sending oil out, will be curious to see if it sees more metal than previous analysis. I wish I'd done compressions checks before pulling the cylinders. Last compressions were all over 70, but it's been a year since they were done.
 
denverpilot said:
Our news back from Annual this year is that we’re at 1269 SMOH Which was done in 1992.
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We're at ~1700 SMOH on an engine that was done in 1996. Oil analysis remains normal, filter clean, comps >70, and it runs great, so we'll keep flying it until it tells us otherwise. The engine was done by Mena engines in Arkansas, and they supposedly have a good reputation.
 
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Salty said:
...I'm sending oil out, will be curious to see if it sees more metal than previous analysis. I wish I'd done compressions checks before pulling the cylinders. Last compressions were all over 70, but it's been a year since they were done.
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:popcorn:

As someone who has never spent a cent of his aviation budget on oil analysis, I am curious what the results will be. How many hours between the last oil change and taking the engine out of service?
 
A quart every 5 hours I wouldn't call "only" on oil consumption. For a little 4-cylinder that's a pretty high amount of consumption.
 
Can someone explain the advantages of chrome cylinders...because unless you have a chrome cam, what’s the point (I’m assuming rust resistant is it’s selling point)?
 
teejayevans said:
Can someone explain the advantages of chrome cylinders...because unless you have a chrome cam, what’s the point (I’m assuming rust resistant is it’s selling point)?
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Back when they were popular, the chrome process was both a way to “harden” them and also to build a layer of metal up on reused cylinders to get size back into tolerances, from everything I’ve read. Common on reworked cylinders I think.

But I’m no engine guy when it comes to airplanes. That’d be Ted...
 
Ted DuPuis said:
A quart every 5 hours I wouldn't call "only" on oil consumption. For a little 4-cylinder that's a pretty high amount of consumption.
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Well, maybe, but it seems like broken rings in 3 cylinders would burn more than that.
 
Salty said:
Well, maybe, but it seems like broken rings in 3 cylinders would burn more than that.
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Not necessarily, especially since they were compression rings and not oil control rings.
 
Thanks Mr. Salty for sharing! I work on motorcycle engines (just my own), it's cool to see the equivalent hardware in your airplane.

That broken ring thing blows my mind! I picture the rings compressed in the piston grooves inside the cylinder. Unless the end gap was horribly wrong, and even then, my mind can't fathom how the rings broke like that.

I am not exactly a storied mechanic, so maybe this happens more than I hear about, but wow!
 
Besides just wearing out and cracking and breaking, aren’t most events that bust up rings precluded by detonation?

Obviously these with as many hours as were on them could have just been fatigued, but in newer stuff do you engine guys usually see preignition and overpressure breaking rings?
 
denverpilot said:
Besides just wearing out and cracking and breaking, aren’t most events that bust up rings precluded by detonation?

Obviously these with as many hours as were on them could have just been fatigued, but in newer stuff do you engine guys usually see preignition and overpressure breaking rings?
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It was my job to detonate engines for a living and I never saw a broken ring like that. It's also almost impossible to make that particular engine type detonate. If it had pre-ignition, it wouldn't still be running.
 
Ted DuPuis said:
It was my job to detonate engines for a living and I never saw a broken ring like that. It's also almost impossible to make that particular engine type detonate. If it had pre-ignition, it wouldn't still be running.
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So what do you think could cause that?
 
Ted DuPuis said:
It was my job to detonate engines for a living and I never saw a broken ring like that. It's also almost impossible to make that particular engine type detonate. If it had pre-ignition, it wouldn't still be running.
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Hmmm. Interesting. So metallurgy problem with the rings, or installation problem? Maybe?
 
Salty said:
So what do you think could cause that?
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denverpilot said:
Hmmm. Interesting. So metallurgy problem with the rings, or installation problem? Maybe?
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Age, isolated rust spot that caused a weak point where it broke over time and then allowed it to continue breaking... bunch of potentials.
 
denverpilot said:
I think that’s Charlie’s way of saying, “Well you broke what didn’t need fixing, now don’t break it even worse putting it back together!” :)
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Well from reading this whole thread, it's pretty clear that if that's what Charlie was saying, he was wrong. Clearly this engine did need fixing and was already broken.
 
charlie said:
I did not say anything about fixing what isn't broken. I was just pointing out some of the pitfalls in putting it back together with the right parts.
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How often do you find rings broke?
 
EppyGA said:
Maybe the thread title should be changed to, "My Engine Was Ready to Fall Out" :)
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"Come from together" would be more appropriate, plus that needs recycled anyway.

oops GRG55 beat me to it!
 
N659HB said:
So I'm curious as to what might have caused the rings to break like that.
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Lots of times the rings will break like that when removed with out supporting them. when allowed to snap as they leave the bore, they will break.
 
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