I am trying to diagnose a problem a 02 trans am with 20k miles and has with 1 noisy lifter on the driver side. the problem started with the initial cam install (T-rex cam) the original installer noticed it has a loud lifter after the cam install (there was no prior issues) and supposedly replaced with new lifters...the problem still continued.

the car was brought to me a year or so later. I suggested a smaller cam for a daily driver (torquer 2) that would be easier on valvetrain. I pulled the heads, had them resurfaced and checked for bent valves/broken springs, installed a new set of LS7 lifters, swapped the sides the heads were originally on (in case the problem came back up I would know its not relative to the heads). started the car and it is dead quiet until the car is fully warmed up, and is driven for about 5 minutes, then the lifter clack comes back. I pulled the driver side valve cover and noticed the only rocker that was "soft" and bled down...it was the 2nd one from the back. I am running out of ideas without pulling the engine and tearing it down. here's a summary of my observations:
--the oil pressure is great. 35-40 psi at idle
--heads have been swapped to opposite sides (ruling out a possible problem with valves, springs, etc)
--rockers and pushrods have been swapped to opposite sides and thoroughly checked for damage
--its not rod knock, exhaust leaks, or piston slap...its clearly a collapsed lifter issue, most likely from lack of oiling somehow
--it seems to just be that one particular lifter clacking...as far as i know through 3 sets of lifters (two that I know of for sure)
--with the valve cover off, and engine running, the first 4 or 5 lifters on the driver side are oiling nicely, and the last few toward the back dont look to be oiling the same as the fronts. they will go for a few rotations of the cam, then spit out a good stream that hits the cowl, while the fronts are a constant amount.

I guess my question is, what is the sequence and pathway the oiling occurs? I tried to follow it the best I could with a spare block I had laying around. from what I can tell, the oil goes out of the pump, through the galley along driver side the block, through the filter, through the plastic "dumbell" in the back, up to the lifter oil galley and pressure gauge port, and goes from there to the cam and main bearings. I dont think it would be a blockage issue without affecting other bearings or oil pressure readings, but could it be a cracked lifter bore? spun cam bearing? possible plug or gasket (on the back of the block) damaged? Is there something simple that I may be overlooking? any other suggestions?

sorry for the long post, but I'm running out of ideas to try without pulling the motor. Thanks for any suggestions.

 

U seem to know enough about building a motor..but ill still ask a stupid question, did u let the new lifters sook in good oil b4 the build/swap?
Next..maybe a blockage somewhere in an oil gallery or even in a pushrod?..

Can u access an engine stethascope?..
I used 1 from my mechanic friend on occasion when im shopping for a car..in ur situation, i believe u can narrow down whats going on..

 

I work on ALOT of LS motors, but I just havent ran into this problem before--no question is a stupid question when you're stumped

I did let the lifters soak for a bit in oil before installing them just to get them lubricated well to go into the bores. this noise will come and go...it seems to be ok when the oil is cold and thicker. sometimes when the engine is hot and you let it idle for a while, the clacking will slowly go away until you hold the RPM's up to 1500 or so and the clacking will come right back when the lifter bleeds back down. I triple checked all the pushrods for blockages and damage last night and they were perfect.

blockage in the lifter oil galley is possible i guess, but it would have to be a big blockage---that galley is a good sized bore, probably close to a half inch in diameter. I was considering the blockage theory, and thats why I was hoping someone would have a schematic of the oil passages in the block because it seems like if there was a blockage inline, I would have problems with other lifters, OR other bearings going bad from oil starvation. This engine has been ran like this for a few thousand miles.

I do have a stethoscope, and i am 100% certain it is coming from the 2nd to the last lifter area on the driver side....just gotta figure out why.

Thank you for throwing me some ideas

 

Not to sound like an ***, did you make sure to face all the bleed holes upto the intake, and check to see if they where all clear. And make sure the lifter tray doesn't wobble side to side. BTW what brand lifters are they. We specifically use howards or morels. Never have problems.

 

my name is does we both have the same problem my ls motor has new cam bearings cam pushrods motor flushed cleaned oil ps cold 55 ps no lifter noise high rpm no noise only at light trottle hears lifter noise

 

WOW i can't believe no one hasn't mentioned replacing the oring at the oil pump. This is CLASSIC symtoms of it being damaged.

 

Oil pressure is fine tho. And it doesn't do it till it warms up. Why would only 1 lifter be starved of oil with a damaged oring? I just don't agree with ya on that.

 

Oil pressure wouldn't be low...just air in the oil and just the way it goes through the system it could effect things in diff ways. I'm telling you your symtoms are classic. quiet till it warms up and the lifter is starved for oil. I'll bet others are too.

 

lifter bore?

 

Carefully replace the oil pump oring!

 

heres what happen to mine when she was starved of oil... btw that was the only lifter that did that, the bearings suffered severely also (none spun) just looked really ate up...

 

I have never had a problem in the past. On the LS7 lifters, the "bleed hole" either faces left or right when in the lifter retainers. the lifter is cut down around the center so oil can surround the bleed hole no matter what orientation it sits in the lifter bore...unless I am not understanding what you are saying correctly.

I hope not, but if replacing the pump o-ring doesnt cure it, that is the ONLY thing left.

I put a bottle of lucas oil treatment in last night for ***** and grins to see what would happen with thicker oil. It seemed to definately help. I drove it about 5 miles further than i have before, then it started clacking again..but it seemed to quit clacking a little faster than before, also.

It seems to only make the noise around a constant1500-3000 RPMs. if I let it idle, the clacking will quiet down and disappear...if i bring up the RPMS to 4000, it seems to go away also.

At first, I didnt think that the pump o-ring would cause a problem like this because I have pinched one before and you can tell right away that something wasnt right with oil pressure and priming. but if it is a small cut, or just old and shrank in size, it would introduce air/foam in the system. I just dont understand why Im having problems with just the one lifter making noise. It would explain why the rear rockers werent oiling the same as the fronts, and sparatically spitting oil out further than any others--possible building up air pockets.

also, it gives me a little hope becuase that o-ring is the ONLY thing that has been untouched since the original installer installed the cam and ported oil pump... and it hasnt been changed out or inspected since the problem started. When I put in the smaller cam, i didnt take off the oil pump because i Just figured it was a bad lifter.

I will change the o-ring out this weekend and let you guys know what happens. Thanks for the suggestions, if anyone has any other ideas to check while i have the front of the motor off, please let me know.

 

I am STILL fighting almost the same exact scenario... I even tried a new o-ring and that didnt help at all.. I broke down last week and took the car to Katech Engineering and they tore into the top of the motor and verified all the valvetrain components were correct and confirmed everything was right and matched.. They checked cam lift, valve springs, heights, coil bind, rockers, pre-load, valves, broken springs, etc. - everything was perfect.. Rear lifter pass-side still clatters inconsistently when the oil is hot and you hold it around 18-1900.. quite when cold, quiet at idle.. They pulled the fill cap and suggested the top of the motor/ valvetrain is getting insufficent oil... No reason why though?? Just that they would have to tear into it to investigate further.. My motor has a new lingenfelter hi volume oil pump w/50psi hot idle... brand new ls7 lifters.. etc.. all brand new.. Very interested in what you can find out...

 

Likewise. Please let me know if you find out anything.

 

Well I got it tore down today, this is what I found:



I'm surprised it held the oil pressure it did with that much of the o-ring missing. I'm glad its fixed and that I learned quite a bit from all this. Thanks for your help guys!