Re: mitigating too high compressoin
Hey guys - all good questions, and I should have specified a couple things. First, I am switching heads and as asked, I am moving away from vortecs. So really the head swap is the genesis for this whole thing. One head had a crack. I have been running approximately 34 degrees total timing and have not experienced detonation, but we have had a very tough time getting this thing tuned right, and it just seems to never really be spot on. The cam in the motor now is relatively tame. I don't know the specs unfortunately. My gut tells me there is an issue with the cam. It was custom designed to work with fuel injection, and it did actually work well with that.
Also of note is application - This motor is getting moved to either a boat or a truck, and that is why I'm interested more in grunt, driveability, and overall tame manners. Going to run 1.6 roller rockers, and dyno results with the GM 383 cam and those rockers has been very respectful, all with great idle and vacuum. Agreed that there may be some left on the table...
So as questioned above, I have not experience detonation. The obvious next question is 'why would you expect too now'? That is where the mild cam comes in. I'm wondering if that will be a problem. I had an engine builder locally who turned out to be somewhat questionable set this combo up. He was unable to get it perfectly tuned. A buddy and I got it much closer, but still not perfect. Absolutely driveable, and actually ran sweet, but not what you would call 'perfect'. The unknown to me is the current cam, and I'm thinking for the small cost of a new one, it is worth getting something that I know what it is.
97 Caiv - I appreciate the cam suggestion. That actually takes me to my next question. What would you guys suggest for a cam if driveability, grunt, liveability was the main goal... if I don't go with the GM cam?
I also agree with the head gasket suggestion, that tight quench assists with detonation, and will move in that direction. Need to figure out how far in the hole I am currently.
Again, thanks for the time put into this.