piston slap or lifter gone bad??????... video

[malibu795]

http://www.youtube.com/watch?v=4BH0AVS8r6g


only here it below 1500rpm and goes away under load

all cylinders were between 118-122psi

used a IR gun to check EGT or the tubes all in *F at 180* coolant temp and 750rpm.
1. 512 2. 470
3. 420 4. 402
5. 340 6. 450
7. 530 8. 410

IMO #5 is then problem... what excatly i dont know..

 

[Al]

Sounds like a ticking lifter to me.

 

[malibu795]

could the lifter bore be gummed up?
failed lifter?


can i swap the lifter out for a new one or need to swap entire cam shaft?

 

[Ed Cannon]

Def sounds like a lifter to me. I would take the v covers off and start looking for lose rockers.

 

[malibu795]

and if all rockers are tight?

 

[Ed Cannon]

and if all rockers are tight?

I would get some oil deflectors or make something to stop oil from going every where and run it with the covers off and feel for the one making noise. A backed out rocker stud, bent push rod a bad lifter or a cam lobe going away will all make noise like this. Even a fuel pump push rod.

 

[LS6 Tommy]

It's hard to ID noises from video, but it sure sounds like a bad lifter to me. Could also be rod a bearing, too, considering it goes away under load. Is it more of a "tick" or a "thunk"? The cylinder pressures lead me to think it's not piston slap. Worn pistons/rings/wrist pins would most likely have lower pressure.

Tommy

 

[malibu795]

It's hard to ID noises from video, but it sure sounds like a bad lifter to me. Could also be rod a bearing, too, considering it goes away under load. Is it more of a "tick" or a "thunk"? The cylinder pressures lead me to think it's not piston slap. Worn pistons/rings/wrist pins would most likely have lower pressure.

Tommy

mains and rods bearings are new.

crank is worn towards the looser end of the tolerances.. and is already .010 under.

since #5 is the coldest cylinder... reason say that one or both vlvs sticking open?

 

[LS6 Tommy]

mains and rods bearings are new. since #5 is the coldest cylinder... reason say that one or both vlvs sticking open?

Cylinder pressure would be low. No one asked yet- what's your oil pressure like at idle & under load? Could be a collapsed lifter. They sometimes pump up as oil pressure increases & get quieter.



Tommy

 

[malibu795]

mains and rods bearings are new. since #5 is the coldest cylinder... reason say that one or both vlvs sticking open?

Cylinder pressure would be low. No one asked yet- what's your oil pressure like at idle & under load? Could be a collapsed lifter. They sometimes pump up as oil pressure increases & get quieter.



Tommy

with a HV oil pump..and everything heat soaked at temp... with 10w-40
800rpm idle is 25psi
2000 no load 60psi
2000 cruising 58psi

does burn oil...~1qt per 1000 miles or so