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Lifter Failure

RV8iator

Well Known Member
Benefactor
I have (had) a Titan DIOX370 on my 8. Great engine and ran trouble free for 5 years/ 950ish hours. Started burning oil like crazy but everything else was right where it should be. Good compression, clean pipes and plugs but dirty oil and using a quart about every 3 hours like a switch was flipped. Found a collapsed breather hose, replace and thought I was good to go and lucky that the crank seal stayed in. Talked to engine shop and thought I had glazed cylinders or just broke a ring or any other myriad of things that can go south in a cylinder, so off to JB's for a top inspection and top overhaul as required.
They pulled a cylinder and found this..

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you can see how the lifter is just coming apart and the scored crank in the background. This is lifter part number 7287R and it seems these came from a batch in late 2012ish that may have been produced with improper hardening done.

and this. You can see how the cam lobe is chewed up also.

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and this. Another view of the top of the lifter. You can see how clean the inside of the engine was.

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It has been five years and 950ish hours since new. I have never gone more than 2 weeks between flying, usually much more frequently than that, changed oil and filters religiously every 50 hours at most, sometimes at closer intervals and used CAM GUARD for the past 3 years since I got out of flying shows very, very regularly.

I'm posting this just as a heads up that if you have an engine from this time frame, really watch those filters at oil changes. Mine went from clean to full of very, very fine black dust that was not visible, but a magnet picked it up after the filter was washed and dried. This happened very fast once the metal started circulating around.

This is not meant to be any kind of negative thread, just a heads up and a reminder to really, really check those filters when changing the oil. There were warning signs to me in the oil consumption and I just happened to have the filter laying in the trash from the change preceding this one and after I washed the mesh and ran a magnet over it I found a little of the ferris metal there. I'm sure going forward I will be much more diligent when inspecting used filters. Absolutely nothing visible, but the old magnet found it. If your engine was produced in this time frame, I would keep an eye out.



New Superior engine is already built and almost ready for installation.
 
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Interesting pictures Widget - they look just like the “bad” lifters that they pass around at the Lycoming engine school - good to low that the engine will keep running with the surfaces that bad!

The warning we got in class as that there is a very thin nitride surface on the face, and when it goes, you have to throw the thing away - some people will try to machine the surface smooth again, but the nitride layer is gone, and that is the hardness - so the repair doesn’t last very long.
 
thanks for sharing Jerry.

Bad luck indeed. Probably would have been picked earlier with an oil analysis, not that it would have had any other outcome, once a lifter and the cam are fried... too late anyway.

Best of luck with that new engine!
 
point in picking it up earlier?

point in picking it up earlier? apparently the engine kept running fine and would have run some more before the metal really shows up in the filter
 
Sorry to hear of your troubles. That looks like spalling from corrossion. I would expect wear from a non-hardened surface to look very different. The sharp features in the pitting seems to point to corrosion. Hardening doesn't really change the potential for corrosion.

Larry
 
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Sorry to hear of your troubles. That looks like spalling from corrossion. I would expect wear from a non-hardened surface to look very different. The sharp features in the pitting seems to point to corrosion. Hardening doesn't really change the potential for corrosion.

Larry

Well, if it will corrode in a week maybe but that engine has never sat long. According to the engine guru?s that are far brighter than me, it?s the hardening that failed.
Every other engne expert I?ve showed this to said it looked like hardening failure to them.
Maybe you can provide photos of what corrosion failure looks like.
 
If it were corrosion related it would be evident on multiple tappet faces and you'd see signs of rust on other things like mag gears cylinder bores.

Normally you see a little indentation on the tappet faces when new. They're checked individually with a rockwell hardness tester so I think it would be unlikely to see one fail due to a manufacturing defect.

But you have to consider what happens when you run an engine with a lot of on/off throttle movements in the airshow biz. Tappet faces get splash lube so what happens when the oil pressure suddenly goes to zero?
 
If it were corrosion related it would be evident on multiple tappet faces and you'd see signs of rust on other things like mag gears cylinder bores.

Normally you see a little indentation on the tappet faces when new. They're checked individually with a rockwell hardness tester so I think it would be unlikely to see one fail due to a manufacturing defect.

But you have to consider what happens when you run an engine with a lot of on/off throttle movements in the airshow biz. Tappet faces get splash lube so what happens when the oil pressure suddenly goes to zero?

Bob, just trying to understand your last sentence. The tappets get splashed by oil, so what?s suddenly zero oil pressure have to do with that. I also had inverted oil system so mever actually had zero preasure.
 
Interesting pictures Widget - they look just like the ?bad? lifters that they pass around at the Lycoming engine school - good to low that the engine will keep running with the surfaces that bad!

The warning we got in class as that there is a very thin nitride surface on the face, and when it goes, you have to throw the thing away - some people will try to machine the surface smooth again, but the nitride layer is gone, and that is the hardness - so the repair doesn?t last very long.

Do Lycoming lifters not have a crown on them like automotive? Flattening automotive lifters is a death sentence for the cam.
 
Widget, I feel your pain, buddy. Mine did the same thing 150 hours after an IRAN overhaul years ago. But it was A&P-induced. The engine builder removed and replaced the original cam and lifters (2,000 hour parts that looked good) but he replaced the parts in random order rather than in their original locations, and after burnishing things just a bit with crocus cloth.

Two things you apparently NEVER do are to mate up worn cam lobes and tappet bodies with other than original mates, and touch a thin hardened surface with even a mild abrasive for any reason.

He did the repair on his dime, but I wasn't happy with the down time nor that metal had been all through the engine and oil cooler by then. Thankfully failures like this are soft rather than catastrophic. It's disconcerting to drain your oil for a routine change and see oil the color of aluminum roof paint coming out the drain plug. :mad: He and I both learned a lesson that day.
 
It?s only money

I?ve been in fields twice in my 50 plus years of slipping surly?s and I?m so thankful that this was a soft failure. The money part stinks, but in the big life picture it?s well spent.
Like they say, never seen a hearse pulling a U-Haul.
 
Well, if it will corrode in a week maybe but that engine has never sat long. According to the engine guru?s that are far brighter than me, it?s the hardening that failed.
Every other engne expert I?ve showed this to said it looked like hardening failure to them.
Maybe you can provide photos of what corrosion failure looks like.

Your experts are probably right. However, a lack of hardening would leave the steel in it's annealed state and I wouldn't expect non-hardened steel to break off in chunks. It should wear like any other steel part when constantly rubbing with another smooth steel part. Possibly the mfg defect was over hardening or some other heat related flaw.

I am not questioning your expert opinions, just was surprised. Best of luck.
 
Widget, I also feel your pain.

After 34 hrs SMOH, on the second oil change, I found lots of steel in the filter. Engine tear down revealed 5 cam lobes and tappets that looked like yours. The cam was new but the tappets were recon. Best guess was the tappets were incorrectly reconditioned. New cam kit, new oil pump, new pistons, honed cyls, new rings, new bearings.... All the soft parts had steel imbedded (pump housing, piston skirts, bearings) which required replacement. Luckily the crank, rods and case were OK. I also put in a new oil cooler since the manufacturer told me there was no guarantee flushing would get all the metal out. Better safe than sorry I figured. Still going after 200 hrs...touch wood!!

Better to find it on the ground than in the air!

Good luck!

Al
 
Bob, just trying to understand your last sentence. The tappets get splashed by oil, so what?s suddenly zero oil pressure have to do with that. I also had inverted oil system so mever actually had zero preasure.

Any time you have a large RPM fluctuation there's going to be a large change in oil pressure. With a large change in oil pressure you're going to get a loss of splash, even if its momentary. The inverted system does nothing to mitigate this unless you go negative because it takes gravity to move the ball in the check valve.
 
Your experts are probably right. However, a lack of hardening would leave the steel in it's annealed state and I wouldn't expect non-hardened steel to break off in chunks. It should wear like any other steel part when constantly rubbing with another smooth steel part. Possibly the mfg defect was over hardening or some other heat related flaw.

I am not questioning your expert opinions, just was surprised. Best of luck.

Logic does not work here, this is exactly what fatigue failure looks like.
 
Any time you have a large RPM fluctuation there's going to be a large change in oil pressure. With a large change in oil pressure you're going to get a loss of splash, even if its momentary. The inverted system does nothing to mitigate this unless you go negative because it takes gravity to move the ball in the check valve.

OK, makes sense, however, I haven?t been flying formation or acro in almost 3 years. If that was the case, it shouldn?t have taken 3 years and 400 hours to develop should it? And, why just one lifter if it was oil related?
 
Geeze, Jerry!

If I had known your airplane was so disease ridden I would not have flown so close to you all those years. Get well soon.:rolleyes:
 
Looks like a similar failure to the problems Continental was having. I recall it was attributed to a change in the manufacturing process for the lifters that ended in rapid spalling in service. Nothing the pilot could do to prevent and not related to idle time or corrosion, etc. Impacted many late 90's early 2000's engines made by TCM.


http://www.csobeech.com/lifters.html

TCM Bulletin on lifters

195044_three_lifters_tappets.jpg
 
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In full recuperatve mode..

If I had known your airplane was so disease ridden I would not have flown so close to you all those years. Get well soon.:rolleyes:

Thanks Somkey, JB is applying therapeutic measures that will have us on our wings in no time at all. I?m glad we weren?t contagious and you flu through it.
 
Lifters

Looks like a similar failure to the problems Continental was having. I recall it was attributed to a change in the manufacturing process for the lifters that ended in rapid spalling in service. Nothing the pilot could do to prevent and not related to idle time or corrosion, etc. Impacted many late 90's early 2000's engines made by TCM.


http://www.csobeech.com/lifters.html

TCM Bulletin on lifters

195044_three_lifters_tappets.jpg

When I participated in the Superior Air engine build school, my instructor showed me an example of a lifter that looked like number 3 above. He was asked to run that engine until failure. After hundreds more hours he never was able to get the engine to fail... good to know.
 
splash low rpm

I had a problem like that on my engine. After I did a lot of research I came to the conclusion that I think mine was caused from long low rpm idle. I got a engine that was stored for a few years. When I installed it I started it and let it idle for about 10 mins. I also would normally idle out of my alley to try to be nice to the neighbors. Now after the rebuild about 10 secs after oil pressure comes up I go to at least 1200 rpm.
 
Tappet Spalling

In my opinion Lycoming has solved this problem twice. First with the conversion of most production engines to roller tappets and secondly for rebuilders of flat tappet engines the new spec. DLC coated tappets. Yes they are $80.00 + each but experience in the field has shown that they are the solution. I?ve talked to a shop who has taken apart engines at TBO and found the DLC tappets so clean that they cleaned and reinstalled them for another turn.
To be fair I?ve also took apart a 4000 hr 320 with the old spec tappets and they looked perfect as well. This engine was flown alot on hour + trips hence the high time and excellent condition. Bottom line: these engines don?t like to set. I?ve always said in the end it?s cheaper to fly them than let them set.
.
 
Do Lycoming lifters not have a crown on them like automotive? Flattening automotive lifters is a death sentence for the cam.

Yes, and wear of the surface will decrease the crown. Spalling of the surface can still happen even with rotation of the follower face.

Automotive followers were largely chilled iron, with martensitic dendrites formed in the material from the chilled face. The matrix will/can fail though resulting further increase of the contact stresses and a progressive failure.

Slipper followers are a problematic design. Well designed roller followers will last much longer.
 
The cam is not splash lubricated, more of a connecting rod bearing oil leak that is thrown from the space between the crankshaft and connecting rod bearing, this is usually around .002"-.0015" so, cold thick oil, and low idle RPM is bad for cam lobe lube. Both centrifugal force throwing the oil and higher oil pressure lube the cam.
 
The cam is not splash lubricated, more of a connecting rod bearing oil leak that is thrown from the space between the crankshaft and connecting rod bearing, this is usually around .002"-.0015" so, cold thick oil, and low idle RPM is bad for cam lobe lube. Both centrifugal force throwing the oil and higher oil pressure lube the cam.

While I can't argue with your logic here, as I also believe it is true (I always idle at 1000+ after a cold start); However, I don't believe it results in wearing cams or spalling lifters. I can't imagine any plane idling more than those relegated to duty training pilots. From what I have read, engines from flight schools tend to be the most likely to reach TBO of all non-commercial GA. If idling killed cams, you would see a lot more of it in flight schools and instead they seem to routinely make it to TBO before overhaul or just require top overhauls.

Larry
 
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