DIS

[Gregory A. Parmer]

On Fri, 20 Mar 1998, Bruce Plecan wrote:
> OK for a chemical engineer inert would be the wrong word, but GM

I s'pose I left out the ":)"...I was considering that everything
remotely close to my car is contaminated somehow. Especially
the nut behind the wheel.

>   Let's use some real numbers, for a Comp Cam 12-211-2
> the events are      Open                  Close
>   @ .006"  intake  29BTDC           61ABDC
>                exhaust  69BBDC           21ATDC
>   "IF" this cam was used in a turbo motor with a total advance of 
> 15d BTDC, the intake valve would have been open for 14d........
> If say it was running 20 PSI of boost then there would be lots of
> fresh fuel/air mixture present....

Thanks for "calling" me on that one. My Crane is advertised to open
the intake at 34d BTDC. It also makes sense that low RPMs (ie less
advance) would make it worse. Sounds to me like high boost, long
cam and DIS is indeed on thin ice (just as Clive pointed out).  
Some of you folks have all the problems the rest of us long for. My long
cam and DIS are on different cars! The turbo will prob'ly never
happen here.

>   Cheers  Bruce    Finely honed point on this Cone Shaped Hat

No doubt. Measure *very* carefully. With high timing you detonate
the bottom end out and too low you blow back through the top.


-greg          Polished conehat courtesy of Bruce and Clive