Ok here's what happened at the drag strip made two time runs and then first round of eliminations i get to about the 1/8 mile mark and the motor will not pull anymore past 5200 rpm. At the end of the 1/4 mile it has always pulled to 6000 rpm with ease. Well on the way back to the pit's i start smelling a strong gas oder, So i lift the hood and check everything out and find that my fuel pressure is 14 psi and is pushing fuel pass the carb floats and flooding out the motor. So i replace the fuel regulator with a spare one that i had with me and set it to 6 1/2 psi. Everything seems ok at this time so i take it for a test run and it still will only pull to 5200 rpm. I call it a day and take the car home. I pull the distrib and check both camshaft/ distrib gear and they are like new. Thanks to the gear oiler i installed. Pull the valve covers and check the valve train and roller rockers look ok. start the motor and let it idle and watch the rockers in action and it all checks out ok. Pull the spark plugs and find that #8 plug gap is almost closed up and is black and sooty. Well' Well' Well'...... I have been racing this car all year long with no problem and when i last installed the plugs they were gapped and indext. So i button everything up and install new plugs gapped at 45 and take it for a couple of test run's and it pull's right to 6200 rpm with ease and is back to normal. Pulled the #8 plug a couple of times and all seems fine. HAS ANYBODY EVER HAD THAT HAPPEN.....Would the flooding cause that. o No: Billy.
Could be a long shot but whats the possibility of a piece of carbon coming loose and wedging between the piston and electrode long enough to close it up? For that matter any piece of trash that might have gotten by the air filter. Maybe a frag of metal left from the porting process?
Had that happen on a SBC dirt track racing engine once. But the plugs were not black and sooty... Never did figure out what caused it. Bert
My guess is that it was from the regulator going bad. It caused the motor to run rich which heated up the spark plugs to the point of getting the electrodes hot enough to close the gaps. o No:
Do you have to index the plugs to keep them from hitting the piston? Did it pull to 6000 in 2nd? I would not think one foul plug would hinder it to add revs past the 1/8 mile. My guess is the xtreme rich condition coused that stall but the plug has been closed up for longer period of time. rich condition cools down the combustion Was the car consistent on the time runs as it has been before?
It"s Alive" and breathing again..... Hi, I am using autolite #24 spark plugs and i just index them for good practice. All my other plugs looked good, The only one i had a problem with was #8 plug and it's ok now. Yes the motor now pulls fast and strong to 6000 rpm in 1st, 2nd, 3rd and it is consistent again. It was consistent on the time runs and then slowed up on my first round of eliminations Thats when i encountered the fuel problem. It seems to be doing fine now. Billy.
Years ago, I had an aircleaner stud that had an extension of about 1/2" long, it worked loose and went down the carb and into the cylinder, it happened at idle and was shut off after a few revolutions (I could hear it ting in the exhaust) I pulled the plugs and found one electrode closed. Pulled the head and there the little stud was on top of the piston of that cylinder. No other damage in this case. In other words, possibly something small made it's way through and on it's way closed up the plug.
Did a couple more test runs. Pulled all plugs and they look good. Also brought #8 piston to TDC and went in through the spark plug hole with a small magnet probe and did not pick anything up. Just wanted to double check everything and it seems ok now. :beer Billy.
hydralocking (sp?) will cause a plug gap to close up. Seen it happen on our snowmobile race engines...
