L5p lifter failure

bimmer95

Member
Mar 15, 2019
41
4
8
Morgantown Pennsylvania
Wondering if any of you l5p gurus have some failure analysis input for me.So this truck came to me with a miss on one cylinder and a pop out of the intake,pulled the valve cover and found the valve lash extremely loose across the board,so loose one of the valve bridges had come out.Tore the heads off and pulled the lifters out and this is what I found along with the other lifters which all have loose follower bearings.Truck has 158k,towed its whole life,and was serviced with amsoil every 5 to 7k miles..Any thoughts on what could have caused this?I have found there is not a lot of info online on l5p internals.Gale Banks of course but in his book the l5p is perfect so nothing much goes wrong....


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hntngkd

Member
Jun 24, 2013
149
1
18
Attica, Mi
Not nearly this bad though. it happened 1 cylinder at a time over the course of a few hundred engine hours. And if i remember correctly it was primarily on the exhaust side.
 

bimmer95

Member
Mar 15, 2019
41
4
8
Morgantown Pennsylvania
Since you mentioned it,I rechecked the intake vs exhaust followers and the exhaust is consistently worse although there is still wear on the rest.Which makes sense the exhaust valve will just open harder then the intake generally..I'm at a loss of why gm would change a perfectly good and proven design of the the 1-16 and change to a lifter with smaller bore and smaller roller follower diameter..also on oil starvation,I've been trying to figure out how the rollers even get oil?there are no feed holes that I can find,only way in is the bottom of the lifter

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JoshH

Daggum farm truck
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Feb 14, 2007
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I have never seen a lifter failure on any 01-16 Duramax. Figures GM would ruin a good thing.
 
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kidturbo

Piston Tester
Jul 20, 2010
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Ya'll scaring me now. Just getting ready to marinize one to prove Gale isn't trying hard enough to kill it.. Now ya tell me I'm gonna wipe the cam out in first 100hrs of thrashing one. Buzz Kill. 😂
I've actually killed one set of LBZ/LMM lifters. Left em in a bucket in bed of my truck for a week full of rain water. They never actually failed, but am willing to donate to anyone who doubts me..
 

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