powermyster
Well-Known Member
Hi All,
I have been trying to solve an issue I've been having with no avail. I thought that I'd swallow my pride and ask for help! I haven't done anything with the car in months as I went back to college. I've been back at it and I'll try run down through everything I done, though some of it might be a little fuzzy as it was done last year.
The car was pinking and backfiring through the exhaust and running a little poorly when I got her, when i checked the timing it was i think about 18* but was pulling in a massive amount of mechanical advance up over 50* IIRC.
I got the FBO limiter plate, set it up to come all in at 34/35* with an initial of 18. Put new rotor, cap, plugs, leads etc. then car ran ok and revs up slowly ok, but if you snap the throttle open she will backfire through the carb every time.
I stripped and cleaned the carb, replaced gaskets and PV. still doing the same. I replaced the accelerator pump squirter with a .035 and have tried all the cams, some seem a little better but she still backfires if I snap the throttle open. I put and AEM UEGO gauge in and have the idle set at about 12.5/1. she leans out and pops every time.
I've the checked the compression, cold (hadn't ran in several days) and dry. getting around 120 psi on most cylinders with a small amount variance, the biggest variance was cylinder 2 about 128 psi and and cylinder 5 which was 113psi. the plugs to the rear of the engine appeared wet when we pulled them, like fuel on them, plus 6 seems to have a little oil on the threads. I havent pulled the rockers covers yet, as she pulls steady vacuum, last reading was a steady 21 inches when I was playing with the timing. I thought that seemed a little high, she seems to like about 30* initial when setting it via rpm, but that initial is too much under load.
I think that I have covered off most of what I have done, carbs are hard to come by in Ireland, there is a guy selling a Holley 650 2BBL about an hour away, which I was thinking of buying to rule out the carb.
Any advise, someone suggested my dissy could be at fault, i did note she seems to retard a little before advancing when I had the light on it. By the way its a standard mopar HEI ignition, checked the connections and earths too.
I have been trying to solve an issue I've been having with no avail. I thought that I'd swallow my pride and ask for help! I haven't done anything with the car in months as I went back to college. I've been back at it and I'll try run down through everything I done, though some of it might be a little fuzzy as it was done last year.
The car was pinking and backfiring through the exhaust and running a little poorly when I got her, when i checked the timing it was i think about 18* but was pulling in a massive amount of mechanical advance up over 50* IIRC.
I got the FBO limiter plate, set it up to come all in at 34/35* with an initial of 18. Put new rotor, cap, plugs, leads etc. then car ran ok and revs up slowly ok, but if you snap the throttle open she will backfire through the carb every time.
I stripped and cleaned the carb, replaced gaskets and PV. still doing the same. I replaced the accelerator pump squirter with a .035 and have tried all the cams, some seem a little better but she still backfires if I snap the throttle open. I put and AEM UEGO gauge in and have the idle set at about 12.5/1. she leans out and pops every time.
I've the checked the compression, cold (hadn't ran in several days) and dry. getting around 120 psi on most cylinders with a small amount variance, the biggest variance was cylinder 2 about 128 psi and and cylinder 5 which was 113psi. the plugs to the rear of the engine appeared wet when we pulled them, like fuel on them, plus 6 seems to have a little oil on the threads. I havent pulled the rockers covers yet, as she pulls steady vacuum, last reading was a steady 21 inches when I was playing with the timing. I thought that seemed a little high, she seems to like about 30* initial when setting it via rpm, but that initial is too much under load.
I think that I have covered off most of what I have done, carbs are hard to come by in Ireland, there is a guy selling a Holley 650 2BBL about an hour away, which I was thinking of buying to rule out the carb.
Any advise, someone suggested my dissy could be at fault, i did note she seems to retard a little before advancing when I had the light on it. By the way its a standard mopar HEI ignition, checked the connections and earths too.
