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Strange looking cylinder wall

Thank all contributors ........

.... for posting this saga for all to read. VERY intersting and educational! Sorry it has to be at someone's (considerable) expense.
 
DanH said:
Kevin, when you get those tappets out, check the part numbers for 15B26064.
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Dan,

What's the story on the 15B26064 tappets? I see that Lycoming SI-1543 calls for their replacement, which certainly hints at a significant number of in-service issues. Assuming that Aerosport complied with this SI after my first cam/tappet issue, I shouldn't have any of those in my engine.
 
Kevin Horton said:
Dan,

What's the story on the 15B26064 tappets? I see that Lycoming SI-1543 calls for their replacement, which certainly hints at a significant number of in-service issues. Assuming that Aerosport complied with this SI after my first cam/tappet issue, I shouldn't have any of those in my engine.
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I have nothing specific, just the same suspicion you have...that they were found to be a problem. The SI is all we're likely to get from Lycoming. The overhaul shops will no doubt have anecdotal information.
 
erich weaver said:
Interesting. Especially after skimming through this long winded article

http://occonline.occ.cccd.edu/online/rfoster/The Rest of the Story- Valve Lifters and Tappets.PDF

It's scary what you find googling lycoming tappet failure

Erich
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That is a very interesting article. Can anyone point to a follow-up that may have been published? Looks like that article was originally printed in or before 2004. Any further information generated in the subsequent twelve years should be of great interest.

Also, it would be interesting to see if the Service Instruction for external oil lines mentioned would be applicable on more engines than just the Mooney application.
 
Google should do it

Try googling: Bill Marvel and Bill Scott

It comes up for me the 5th link down. Subject: Lycoming Valve Guide Distress ? Next Steps Folk...

Ed
 
Kevin Horton said:
I saw some old info from Lycoming when they first started offering roller lifters that said that they could mod cases to add these to engines in the field, but I don't know if that panned out or not.
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The answer is yes...maybe. Some cases can be modified, some can't - depends on how much meat there is in the casting. So definitely worth checking, but beware, the camshaft also has to be changed when you change to rollers.
 
Is there evidence that the roller lifters give longer service?

Seems like it would take a large fleet operator a long time to establish any differences.
 
Good catch Kevin. To have such an issue in four years, I would be highly suspicious about the heat treating. The intake lobes are shared so they do twice the work and take out the other lifter if there is a failure.

In this part of the world, it is well known that Lycoming had a bad batch of these parts. I'm not sure which part number it was, but they were the ones immediately before the hyperbolic units. Enough spalled that at least one major engine builder only puts Superior P/N SL72877 lifters in now (will not buy a Lycoming cam kit which says something as they probably forego the Lycoming warranty by doing so). They will not touch the new hyperbolic units either.

It seems that Superior still use the original manufacturer which industry found to be reliable.... so there is probably some truth to a high failure rate with the superseded parts. Anecdotally, Lycoming change part numbers whenever they change supplier.

I have heard the Lycoming rep tell people that the roller cams completely cured the problem with spalled lifters (no kidding they removed the lifters). There have still been issues with the roller cams though. Not to mention the rollers are mandatory replacement at overhaul/prop strike.

If it were me, you have a reasonably low time engine. Assuming you have the time and can find someone with experience to help you, I would pull it apart and do the job yourself.

Sounds like you have made very little metal at this point, so you may well do well. Looks like you have a cylinder to hone/replace and cam/lifters to go in. If the oil filter has done its job, the bearings and crank will be fine. You may need a new oil pump housing or resurface of the pad - but this is easy to get done. Make sure to check the accessories for metal too.

If you really want an engine with roller cams I would just buy a new one from Vans and sell the current unit once repaired.
 
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Ironflight said:
Wow Kevein - ugly isn't a strong enough word for that tappet face! Even the "ridiculously beat up" examples at Lycoming school didn't look that bad.

Is this a first-run engine, or was it built up as an overhaul? If its first run, there has been something going on in there that wasn't right in the first place.

Paul
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I agree. This doesn't look like any kind of "wear" that I have seen on any part. It appears that the metal has been flaking off, possibly due to improper metallurgy or casting. Even the pictures of the corrosion induced wear that I have seen look nothing like this.

Very unfortunately that the defective part will require a tear down.

Larry
 
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