Hey guys... This is rather long, but I appreciate anyone take the time to read it... I know I'm not an LS1, but hopefully you can help me out anyway... Here's my problem... I've just finished building my 93 TA... I had a custom grind made by cam motion... I put the motor in... got it started, and was ready to begin tuning... I've put a couple hundred miles on it, but for some reason it would keep fauling plugs on a few cylinders rather quickly... I went through several plugs on each with the same result... My next thought was to check cylinder pressure... It turned out, on most of the cylinders, I was making anywhere from 60 to 80 psi whereas it should be in the 140 range... So from there I loosened all the rockers, looser than 0 lash... all 8 cylinders made between 140 and 150 psi... So I assumed I just had the valves set to tight... This is a hydraulic roller by the way... So I re-adjusted the rocker... setting each a 1/4 turn from 0 Lash... But to no avail... I still had the same problem... So I set all the rockers to 0 lash, no more no less... I was lucky to make about 20 pounds more on some cylinders but still much less than 140 psi... So I called Cam Motion and they said it sounded like my lifters were bad and told me exactly how to adjust them when I put a new set in... I had brand new Crane hydraulic rollers... But ok... If thats the problem then I'll change them... So I spent the money on a new set of OEM's, got them in, adjusted them properly, and what do you know... NO PRESSURE!!! So I loosened all to less than 0 Lash and all cylinders made 140-150... Now I'm really confused... I don't know what else to try... To me it seems like theres something wrong with the overlap or timing of the cam... Does anyone have some suggestions? I appreciate anyone taking the time to read this... Thanks alot...

Mike

 

cam specs will affect cylinder pressure...changing rocker lash is effectivley changing valve open/close time