MY FYN 79
Jul 17th, 05, 8:18 PM
For those with decent sized roller cammed small blocks, what are you running your base timing at?
For reference, my cam is a hydraulic roller with 234/238 @ .050 on a 108 LSA in a 10.3 to 1 383. It has 1.6 rockers on I/E.
I'm having a situation where I cannot get my 750 HP carb to idle without fouling plugs. Right now the motor has around 21* of timing at the 1150ish RPM idle, and no amount of carb tuning can get it to idle clean. Turning in the idle mixture screws enough to clean it out ends up with the car not restarting without pumping the gas, and surging during light acceleration.
Fattening up the idle mixture enough to get it to restart *better*, ends up with fouled plugs and poor drivability in town from being overly rich. WOT action is great, as even from a sub 1000 RPM idle I can pin the car with no hesitation at all.
The carb just came back from a very reputable shop, and he walked me through all the common problems to check for. All was well. We are looking into the possibility of needing more base timing. I manually turned the distributor and gave the car 36* timing at idle, and the starter had no problems refiring the motor even at 200*... but even with the 36* of timing, the car still didnt restart good after it sat a few minutes.
I dont really want to lock out my distributor on a street car, as I dont feel that should be necessary. The only problem is that my distributor doesnt have a vacuum advance, but none of my others did either with bigger cams than the one I have now. Any bits of advice? More specs can be provided if needed. This problem has kept me from going to the track for the last two weekends. :mad:
TIA for any thoughts.
For reference, my cam is a hydraulic roller with 234/238 @ .050 on a 108 LSA in a 10.3 to 1 383. It has 1.6 rockers on I/E.
I'm having a situation where I cannot get my 750 HP carb to idle without fouling plugs. Right now the motor has around 21* of timing at the 1150ish RPM idle, and no amount of carb tuning can get it to idle clean. Turning in the idle mixture screws enough to clean it out ends up with the car not restarting without pumping the gas, and surging during light acceleration.
Fattening up the idle mixture enough to get it to restart *better*, ends up with fouled plugs and poor drivability in town from being overly rich. WOT action is great, as even from a sub 1000 RPM idle I can pin the car with no hesitation at all.
The carb just came back from a very reputable shop, and he walked me through all the common problems to check for. All was well. We are looking into the possibility of needing more base timing. I manually turned the distributor and gave the car 36* timing at idle, and the starter had no problems refiring the motor even at 200*... but even with the 36* of timing, the car still didnt restart good after it sat a few minutes.
I dont really want to lock out my distributor on a street car, as I dont feel that should be necessary. The only problem is that my distributor doesnt have a vacuum advance, but none of my others did either with bigger cams than the one I have now. Any bits of advice? More specs can be provided if needed. This problem has kept me from going to the track for the last two weekends. :mad:
TIA for any thoughts.