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355 chevy

2K views 3 replies 2 participants last post by  DoubleVision 
#1 ·
i have a 355 highperformance g team highrise intake holley dp forged pistons hydraulic cam&lifters msd 6al ignition, ac yellow short plugs msd wires, sounds like a diesel , builder said it was for racing use 114 octane fuel, is this sound normal, and what can i do make sure its ok to run, dont like sound , with out having to go in motor to change pistons?
 
#2 ·
Well there are 2 "sounds like a diesel" culprits, one is detonation, which can be caused by carbon build up, too high of spark timing, and too much compression for pump gas use, so if your running pump gas in a high compression engine it`ll detonate itself to death and sound like a diesel doing it, if this is the case then when you hear the diesel show up your signing your engines death wish. Second, Piston slap from the extra clearence honed in for the use of forged pistons. But not many do this practice anymore as most forged pistons today don`t expland as much and can almost be fitted as tightly as cast pistons can. Usually, forged piston slap goes away or gets alot quieter when the engine gets hot. Lastly, Excessive cylinder clearence from excessive honing, or excessive wear. You can slow down the spark timing until the detonation stops, but you can bet by the time you get it low enough to stop detonation, it`ll be so low the car won`t have any power, so either your stuck with changing the heads for heads with larger chambers or a piston change is in order. But if 76cc heads are already used on your engine, a piston change will be in order.
 
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