hi i have an 87 lt 500 that runs great except for real bad spark knock when the powerband kicks in,i run golden spec with 93 octane gas. is there some type of timing that could be off and how could i fix it ? Thanks Brandon my email is dirtdogz@1010internet.com

 

Timing usually doesnt slip...if it does then that means the flywheel key has sheared and the engine will either run roughly or not at all.

Carbon build up on the piston can cause an increase in compression that would possibly create some pinging. Check you compression with a quality thread in style gauge(Snap-on is the best). If its abnormally high for a stock engine, you may need to tear it down and remove the carbon from the piston crown.

Coolant mixing with the fuel-air charge will also reduce the octane the level, increase the compression from the steam, and ultimately create pinging or worse detonation. Head gasket leak, known to be a problem with the lt5's. Using coolant???

Lean jetting can cause pinging and detonation. The increased heat created from lean jetting does this. Verify you are jetted right across the board.

Old gas??? Wrong mix ratio???

 

great post


could also be sloppy piston (skirt rap) or a rod ?