Spark Knock

[dlg423]

I'm getting spark knock with my GM crate engine 9 to 1 compression ratio, using 89 octane gasoline. I've tried adjusting the edelbrock carb and have it set for a rich mix, just short of over-rich. The timing seems to be ok as well. I hate spark knock but do not want to throw money down the drain by using 93 octane. any ideas?

 

[bradfordsvettes]

are you running an egr valve if not could br part of the problem if you have an egr it may not be working steve

 

[Stallion]

Hmm...that's odd. Your CR isn't high at all, but what kind of cam are you running? Is it low duration and high lift? I would try 91 and see if you still have the pinging.

Good luck!

Stallion

 

[Jack]

I'm getting spark knock with my GM crate engine 9 to 1 compression ratio, using 89 octane gasoline. I've tried adjusting the edelbrock carb and have it set for a rich mix, just short of over-rich. The timing seems to be ok as well. I hate spark knock but do not want to throw money down the drain by using 93 octane. any ideas?

Perhaps the ignition timing needs another look. I'm assuming your new crate motor did not come with a distributor ... are you using the recommended GM dist P/N 1104067 ? If not, the advance CURVE may be all wrong for that motor. Also, did that motor ship with instructions regarding octane requirement?
JACK:gap