on my '91 5.7 TPI...
finally, i'm rounding the final curve on this project and have a couple of ?'s regarding compression and spark plug gap. the 1st ? is (for all you guru's) what is my "stock" compression for a 5.7 TPI? 2nd ? is, is it affected by changing the cam and rocker ratio? (now running .525 on the lift, int/exh, w/1.6 rockers) the heads were machined for a 3-angle valve seat, but no "porting" or bowl work. so, with all that said, if my compression is changed, how do i know what it has changed to, and do i need to change the spark plug gap because of that? stock is .035... also, is it normal to find oily threads on the plugs for the first few hundred miles on a rebuilt engine? thanks, i'm about to sign this puppy off, other than tuning on the dyno.
finally, i'm rounding the final curve on this project and have a couple of ?'s regarding compression and spark plug gap. the 1st ? is (for all you guru's) what is my "stock" compression for a 5.7 TPI? 2nd ? is, is it affected by changing the cam and rocker ratio? (now running .525 on the lift, int/exh, w/1.6 rockers) the heads were machined for a 3-angle valve seat, but no "porting" or bowl work. so, with all that said, if my compression is changed, how do i know what it has changed to, and do i need to change the spark plug gap because of that? stock is .035... also, is it normal to find oily threads on the plugs for the first few hundred miles on a rebuilt engine? thanks, i'm about to sign this puppy off, other than tuning on the dyno.
Member
9.3:1 Cam, rockers, and valve job wont effect it. The plugs may be dirty at first. If the computer dosent get tuned for the cam they will always be dirty and cause a loss of power an hard starting. Pull them out after a hundred miles, check them and clean them.