Spalled cam and lifter pictures..

dans2992

dans2992

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Dans2992
So, if anyone's interested, here are some pictures of my spalled cam lobes and lifter face. You can see the difference in height between the good lobes and the bad ones. Total repair bill - $15k (plus another $5k of "as long as it's in the shop and torn apart" work)

https://carousel.dropbox.com/photos/cc/m0FuSexPjEYpyH8
 
dans2992 said:
So, if anyone's interested, here are some pictures of my spalled cam lobes and lifter face. You can see the difference in height between the good lobes and the bad ones. Total repair bill - $15k (plus another $5k of "as long as it's in the shop and torn apart" work)

https://carousel.dropbox.com/photos/cc/m0FuSexPjEYpyH8
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Looks like you probably under 230 hp, should be climbing a couple hundred fpm faster now.
 
Lycoming IO-540 in a 67 Comanche 260B


Sent from my iPad using Tapatalk
 
Sorry for the bad experience. The lifter and cam spalling issue has always been a problem. I've seen some Navajo and Mirage engines go so far the the large end of the lifter body actually broke off. Then the engine is pretty much scrap.

If you start seeing small shards or splinter size ferrous pieces in the filter you can be sure a lifter body is spalling.
 
Was this a case of bad luck or did the engine sit inactive.
 
kmead said:
Sorry for the bad experience. The lifter and cam spalling issue has always been a problem. I've seen some Navajo and Mirage engines go so far the the large end of the lifter body actually broke off. Then the engine is pretty much scrap.



If you start seeing small shards or splinter size ferrous pieces in the filter you can be sure a lifter body is spalling.
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Yes, that's how we discovered it - the small shards...
 
RichNY said:
Was this a case of bad luck or did the engine sit inactive.
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According to the mechanic, he thinks it was just bad luck. It has been flying 200 hours a year or so. It did sit idle for six weeks while we re-did the interior.

We even used camguard. The engine sat for several weeks before the mechanics could get to it and when they pulled the cam, there was still oil all over it.
 
Didn't it used to be a common practice to resurface cam followers and reuse and now the common thinking is to replace with new? In my corrosion failure in an 0-320 the cam was a mess but the followers were nearly perfect. Yours is an interesting contrast to mine.
 
I always get an uneasy feeling when I pull a Mirage cylinder because I have found so many wiped cam lobes and lifter bodies. Many were engines operated between 100 and 200 hrs a year. I began seeing a big increase in the problem back in the early 80s.
 
Stewartb said:
Didn't it used to be a common practice to resurface cam followers and reuse and now the common thinking is to replace with new? In my corrosion failure in an 0-320 the cam was a mess but the followers were nearly perfect. Yours is an interesting contrast to mine.
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In the 0-300 and most of the C- series I'm finding the removed parts have already been ground too many times and are under or oversized and can't be resurfaced again.
 
Let'sgoflying! said:
Bad luck? Not a metallurgy defect?
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That's what I have often wondered. The oil and method of operations haven't changed. The materials are the only thing left and they are being supplied by the cheapest vendor.
 
You'd need to know the complete history of followers and cam to make that call. And trust the shop that recertified them if re-used. It is a really interesting topic, why some can go seemingly trouble-free and others fail.
 
dans2992 said:
According to the mechanic, he thinks it was just bad luck. It has been flying 200 hours a year or so. It did sit idle for six weeks while we re-did the interior.

We even used camguard. The engine sat for several weeks before the mechanics could get to it and when they pulled the cam, there was still oil all over it.
Click to expand...

There was a period where Lycoming made soft cams (Chevrolet did as well) and they end up peeling.
 
Henning said:
No no, definitely a materials defect. There are two issues with Lycoming cams, rusting and a run of soft cams.
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It would be nice if Lycoming acknowledged the issues. Repairing their defect was not cheap and entirely on our dime..... :|
 
Henning said:
No no, definitely a materials defect. There are two issues with Lycoming cams, rusting and a run of soft cams.
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this is not correct.

It's more to do with the tappet hardness....and not the cam softness. Hence the reason for the design change to rollers....:rolleyes:

This one is hard to prove and hold them accountable. Good luck....
 
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Checkout_my_Six said:
this is not correct.

It's more to do with the tappet hardness....and not the cam softness. Hence the reason for the design change to rollers....:rolleyes:

This one is hard to prove and hold them accountable. Good luck....
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Soft is relative to the application, you basically just said the cam was soft.:rolleyes: Also Roller tappets have not fixed the problem according to Charie Merlot, so they still may be soft.
 
dans2992 said:
It would be nice if Lycoming acknowledged the issues. Repairing their defect was not cheap and entirely on our dime..... :|
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At Lycoming, denying warranty claims is Job 1. Denying mistakes is Job 2.

The new hyperbolic tappet bodies are a great example. The idea was to let the tappets rock a little to reduce wear. The result was low oil pressure in six cylinder engines. If the case is brand new, pressure will be good for a while. First overhaul with lifter bores measuring well within limits and new hyperbolics, forget it. You'll be lucky to make TBO without screwing in the relief valve all the way. Put the old style lifters in and pressure magically becomes good again.

Lycoming is well aware of the problems reported by almost every engine shop in the country. Their response was to the effect of they can't reproduce the problem with their brand new cases, so they won't fix the problem. Doesn't matter that they are thumbing their noses at customers that need to get more than one run out of their engines. Doesn't matter that the customers cases are within Lycoming's own specifications. Doesn't matter that the new design didn't do a damned thing to help wear.

At least the aftermarket is still producing the superior old style.
 
Henning said:
Soft is relative to the application, you basically just said the cam was soft.:rolleyes: Also Roller tappets have not fixed the problem according to Charie Merlot, so they still may be soft.
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IT's not about the Cam....it's the Tappets. :rolleyes:
 
Checkout_my_Six said:
IT's not about the Cam....it's the Tappets. :rolleyes:
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Then why haven't they fixed the problem with the changes in tappets?:dunno: You sound like a Lycoming engineer in denial.:rofl: There are plenty of ways to make the cam better to eliminate the problem regardless tappet choice.
 
Lycoming has not fixed the problem, simply because it is a conflict of interest. They are in the business of manufacturing and selling engines.

Roller tappets are not the end all fix for cam and lifter problems, They are but another set of problems. any debris in the oil will eventually get caught between the lifter roller wheel and the cam, wear is different, but it is still there. Think about it as running your car tire over a baseball sized stone on the road. It will leave a dent in the road and cause your tire to bounce.
 
dans2992 said:
It would be nice if Lycoming acknowledged the issues. Repairing their defect was not cheap and entirely on our dime..... :|
Click to expand...

If they had acknowledged it, there would be an AD, or at the least an SB, and it would be fixed on your dime anyway. :rolleyes:
 
Tom-D said:
Lycoming has not fixed the problem, simply because it is a conflict of interest. They are in the business of manufacturing and selling engines.

Roller tappets are not the end all fix for cam and lifter problems, They are but another set of problems. any debris in the oil will eventually get caught between the lifter roller wheel and the cam, wear is different, but it is still there. Think about it as running your car tire over a baseball sized stone on the road. It will leave a dent in the road and cause your tire to bounce.
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Absolute pure BULL SIHT....

Tom... You need to stop spreading old wives tales....:mad2::mad2::mad:...

Baseball sized stone being run over by a tire would be like comparing it to squashing a B B sized piece of debris between the cam and roller...

AIN'T GONNA HAPPEN......

Tom.... You need to quit posting idiotic stuff..IMHO...:(
 
They must have made good ones in 1967 because I just checked another oil filter with abiut 44 hours flight time (in mechanical tach hours) from an o320e2d and there wasnt much to look at in it.
 
tlrussell said:
Did you seriously just estimate horsepower from a pic? I hope you use your superpowers for good only. :rolleyes2:
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Yeah, I made a rough guess of loss of horsepower difference from visible difference in cam profile. It's not magic, it's the result of a youth misspent playing with race cars and fixing engines. :lol:

My dad has made a similar comment, "Good thing you're not malevolent.":rofl:
 
N801BH said:
Absolute pure BULL SIHT....

Tom... You need to stop spreading old wives tales....:mad2::mad2::mad:...

Baseball sized stone being run over by a tire would be like comparing it to squashing a B B sized piece of debris between the cam and roller...

AIN'T GONNA HAPPEN......

Tom.... You need to quit posting idiotic stuff..IMHO...:(
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Ya gotta remember all old radial engines had roller Tappets, all had cam ring wear. All had tappet guide wear, all had roller axel wear.

Roller tappets have 4 points of wear the the regular have three.
 
Tom-D said:
Roller tappets are not the end all fix for cam and lifter problems, They are but another set of problems. any debris in the oil will eventually get caught between the lifter roller wheel and the cam, wear is different, but it is still there. Think about it as running your car tire over a baseball sized stone on the road. It will leave a dent in the road and cause your tire to bounce.
Click to expand...

N801BH said:
Absolute pure BULL SIHT....

Tom... You need to stop spreading old wives tales....:mad2::mad2::mad:...

Baseball sized stone being run over by a tire would be like comparing it to squashing a B B sized piece of debris between the cam and roller...

AIN'T GONNA HAPPEN......

Tom.... You need to quit posting idiotic stuff..IMHO...:(
Click to expand...
:rolleyes2: When you are replacing a cam with a >1/8" deep groove worn into it from a roller and it surprises you as much as a leaking strut on a 172, you'll understand.
 
bnt83 said:
They must have made good ones in 1967 because I just checked another oil filter with abiut 44 hours flight time (in mechanical tach hours) from an o320e2d and there wasnt much to look at in it.
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Most bad cams came out of Detroit et al between 1975 and 1986 or so. It was really the perigee in American machine manufacturing. I'm sure Lycoming uses the same suppliers everyone else does.
 
tyndall said:
:rolleyes2: When you are replacing a cam with a >1/8" deep groove worn into it from a roller and it surprises you as much as a leaking strut on a 172, you'll understand.
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There are Detroit Diesels that have been running since 1939 using roller cams and it is a proven concept.... If you REALLY have a roller cam with a .125 groove in it from the roller... You need to be bitching at the manufacturer as they royally screwed up on simple metal to metal matching hardnesses....:yes:
 
Tom-D said:
Ya gotta remember all old radial engines had roller Tappets, all had cam ring wear. All had tappet guide wear, all had roller axel wear.

Roller tappets have 4 points of wear the the regular have three.
Click to expand...

I used to run a 1927 Atlas Imperial Diesel, and a 1918 Pope Hartford petrol, both with external roller tappet cams. You just stop and hit them with an oil can every 2 hrs. I was running these engines in the 1990s and both were pretty much original, and the Atlas was in solid commercial marine service in a big wood boat the whole time. The system is not particularly fragile by nature. If it is weak,mother weakness is in the design and quality control.
 
How many of those radials, with bad cams, had floating cams and clearance improperly adjusted?
 
tyndall said:
:rolleyes2: When you are replacing a cam with a >1/8" deep groove worn into it from a roller and it surprises you as much as a leaking strut on a 172, you'll understand.
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Do you have an example? I'd love to see it. Do you realize some of the very first engines had roller tappets, and that flat tappets were a manufacturing economy?
 
Roller lifters and cam rings have the same problems as all the rest do.
 

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