For those with scan tools (I use Datamaster), what kind of knock counts to you get on a cold start-up? On my 7k mile forged-piston 383 LT1 I'm seeing 4000-12000 knock counts (it varies) on a cold start, through the first 15-20 seconds or so of engine runtime. On a hot start, knock counts are more like what I'd like to see on all starts (1500 area).

Note that a "cold start" for me in Florida really isn't that cold (weather is typically 70-93degrees) for when I've logged this data.

Thanks,
RobY
95Z28

 

anyone?

 

I've seen this before on other engines, both strokers and non. I wouldn't worry about it, it's probably due to cold rockers or something making more noise than normal.

 

I've seen this on mine very often. I think mine is caused by my Street Twin flywheel teeth making so much noise during starter engagement. Who knows????

Steve

 

I also have alot of knock counts on start up and high rpm . I have LT1 edit and can't figure out how to reduce the amount it sees .

 

If your running forged pistons which may have a slightly wider piston to cylinder wall clearance than stock depending on who put the motor together you will get some piston slap on cold startup for a couple of minutes which is normal.

 

Stock here. 63 counts on start up.

Marvin