opinions wanted....cam gurus.
04-29-2009, 08:50 PM
#1
opinions wanted....cam gurus. ok heres a quick run down. i dont know what to do with my cam. i dont know if i should advance it the way it was meant to be or change it. when i installed it i measured ptv and it was very close for my comfort......well dumb *** me. i measured it and didnt account for the .060 preload i already had on the lifters. so i put the cam on a 114 icl. it was ground to be on a 110. i already have a new cam spec'd out but i really dont want to loose any power. ive learned to live with the somewhat poor low rpm driveability but the gas mileage is horendous. i get 10-11 mpg around town. which imo is ridiculous.
motor specs
416ci ls3 block
manley 10cc dished forged pistons
compstar rods/ crank
arp etc etc
tfs 215 cc heads milled to 60cc
stock gm ls3 gaskets (5 layer)
current cam is 247/ 254 comp lsl on a 114 (should be a +4)
cam that was spec'd for me is 239/ 247 113+2 also on the lsl lobes which are .624 lift.
so swap it out or just advance the cam like it was designed to be? i also run a 200 shot on the car and debating going to a 250. current gear is a 4.10 (m6 tranny) and also debating going to a 3.73 as right now i cant cross the traps under power with the 4.10.
if you need more info ask away im sure i have it.
motor specs
416ci ls3 block
manley 10cc dished forged pistons
compstar rods/ crank
arp etc etc
tfs 215 cc heads milled to 60cc
stock gm ls3 gaskets (5 layer)
current cam is 247/ 254 comp lsl on a 114 (should be a +4)
cam that was spec'd for me is 239/ 247 113+2 also on the lsl lobes which are .624 lift.
so swap it out or just advance the cam like it was designed to be? i also run a 200 shot on the car and debating going to a 250. current gear is a 4.10 (m6 tranny) and also debating going to a 3.73 as right now i cant cross the traps under power with the 4.10.
if you need more info ask away im sure i have it.
05-03-2009, 07:54 PM
#4
So when you checked your PTV clearence you had .060" preload on your lifters and you spun the motor over and it the clearance was too tight? Did you use checker springs or your actual valve springs? If you used your actual valve springs your piston to valve clearance could be less than you think because you could have compressed the lifters.
I'm not an expert but my buddies mustang had the cam installed 8 degrees retarded (stupid gear drive) and it was that way for 5 years. He doesn't drive it much (show car) but we just advanced the cam 8 degrees and the car idles better, has 7 more inches of vaccum and has so much more lowend power. Your current cam is huge and I doubt advancing it 4 degrees is going to help much with gas mileage or driveability, I would install the smaller cam. You will have better PTV clearance with the smaller cam and should have much better low end power.
I'm not an expert but my buddies mustang had the cam installed 8 degrees retarded (stupid gear drive) and it was that way for 5 years. He doesn't drive it much (show car) but we just advanced the cam 8 degrees and the car idles better, has 7 more inches of vaccum and has so much more lowend power. Your current cam is huge and I doubt advancing it 4 degrees is going to help much with gas mileage or driveability, I would install the smaller cam. You will have better PTV clearance with the smaller cam and should have much better low end power.
