02 firebird Terrible piston slap
07-10-2009, 05:21 AM
#1
02 firebird Terrible piston slap I just bought a 02 firebird with 31k on the car that has the WORST piston slap i ever heard! when you start it cold its quiet for about 30 seconds then it starts clacking and knocks and clicks and makes terrible noises for about 5 mins until it gets hot then its completely quiet.
THANKS GM
THANKS GM
07-10-2009, 08:50 AM
#3
Its insane...how could it slap this badly, even hot the engine has a weird clatter to it if the piston are unloaded like when it shifts up through the gears. Everytime it shifts at light throttle you hear the pistons slightly clatter. Odd thing is it uses no oil, you would think if it was that loose it would use some???? damit GM !
07-12-2009, 06:09 PM
#4
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My 2000 SS did the same thing. even when it was hot in between shifts just like yours. My friends always talked **** when they heard it......well until they rode in it then the shut up quick. I bought the car at 29k miles and sold it at 78k and had no issues. So i wouldnt worry about it.
07-12-2009, 07:41 PM
#6
Its insane...how could it slap this badly, even hot the engine has a weird clatter to it if the piston are unloaded like when it shifts up through the gears. Everytime it shifts at light throttle you hear the pistons slightly clatter. Odd thing is it uses no oil, you would think if it was that loose it would use some???? damit GM !
Get a QTP cut out so you won't hear it.
07-12-2009, 07:53 PM
#7
Its insane...how could it slap this badly, even hot the engine has a weird clatter to it if the piston are unloaded like when it shifts up through the gears. Everytime it shifts at light throttle you hear the pistons slightly clatter. Odd thing is it uses no oil, you would think if it was that loose it would use some???? damit GM !
The issue lies in two things - the hyperutectic pistons and their short skirts. The pistons expand at a different rate than the cast iron cylinder liner, which causes piston slap when cold. If they decreased the tolerance, you would have issues with the pistons being too close tolerance with the cylinder walls when warm. Its basically a compromise.
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07-12-2009, 09:08 PM
#8
Thanks for the replies, i'm still not conviced this is all piston noise. The car for a very long time since it only has 31k on it, I'm starting to think some of the lifter are bleding down causing noise BUT why would it be COMPLETELY QUIET for 30 seconds on a cold start then make all this clatter? I mean honestly if you heard it you would say WTH is wrong. Another thing i noticed if you raise the rpm a little and get a load on the engine its completely silent again...let it idle and all the clatter comes bk. It has 50 psi oil pressure hot at a idle, higher as you rev it so oil pressure is good. My 99 made simliar noises but not this loud.
