Ive noticed that my engine knocks when its at an idle, and when i start to raise the rpm the knocking gets faster. Edventually at like 1300+ rpm it goes away because the sound form the exaust gets to loud, but I was wondering if everyone had this because my dad has a GM motor too and he said that he actually got the engine replaced because it was knocking and then the new engine did the same thing and thats its normal. I know its not from cheap gas either, so i was wondering if this is common or did i mess up a valve or sumthing.
-
[COLOR=Navy]2000 Navy Blue Trans Am, T Tops, Automatic, Ram Air, Slp 85mm Mas, Air Lid, Smooth bellow, Hooker 1.75 Lt's, ORY, LM1, Air/EGR delete, Throttle body coolant bypass. Msd super conductor wires. TSP cam, ss3600, svo 38LB injectors.
Ported fast 92 mm intake and 92 mm TB on order.
11.539 @ 118.82 1.649 60 foot.
1969 z28 - 9.957 @ 133.92 1.425 60 foot. -
Do a search on "piston slap"
Common issue with the LSx series of motors.Tracy
2002 C5 M6 Convertible
1994 Z28 M6 Convertible
Current Mods:
SLP Ultra-Z functional ramair, SS Spoiler, STB, SFCs, Headers, Clutch, Bilstein Shocks, and TB Airfoil. 17x9 SS rims with Goodyear tires, 160F T-Stat, MSD Blaster Coil, Taylor wires, Hurst billet shifter, Borla catback with QTP e-cutout, Tuned PCM, 1LE Swaybars, 1LE driveshaft, ES bushings, White gauges, C5 front brakes, !CAGS, Bose/Soundstream audio, CST leather interior, synthetic fluids
-
In most cases it is completely normal and will not cause any harm.
When GM went to the hypereutectic (high silicon content aluminum alloy) pistons in the LS1, they utilized a higher ring pack to reduce emissions by helping to eliminate unburned fuel around the sides of the piston crown. They additionally reduced, and in some cases, eliminated the piston skirts altogether. This reduces the overall mass of the piston and makes the cylinder bore tolerances more critcal.
The hypereutectic piston engines are purposely designed so that the piston to cylinder bore tolerances become accurate only once the engine is fully warmed up. This combined with the reduced piston mass and higher ring pack are what you hear as piston slap.
As long as it goes away once the engine is completely warmed up and you are not using an excessive amount of oil, it is nothing to worry about and completely normal.Comment
-
is it possible its noisy rockers and vavle train like a loose one.2000 trans am auto, Afr 205,tr 220/220 112, mti lid, 160t,umi sfc,hooker headers and ory y,loud mouth. bellow,pr's,harland rockers,new lifters,ls6 oilpump,rollermaster doubler roller, msd wires.
Comment
-
Best thing to do is to post a sound clip or video if you have the means.Originally posted by joe ws6Comment
Comment