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#1
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popping: carburetion? ignition? or?
i was hoping i could get someone to help me troubleshoot the following.
400 small block up to 4500 rpm, 4150 mechanical double pumper with stock out of the box setup, stock distributor with new hei in-cap and rotor, solid copper core wires, accel shorty plugs non-resistor. i would take the nova out for a drive, and the engine fully warmed up. normally i drive with the lightest foot... and everything's fine. but under hard acceleration, opening up the carb to WOT, i would occasionally experience what sounds like a tight metal cable snapping loudly, what feels like the engine stopping for a moment, and then continuing normally. i thought i was lean for a while... i checked the plugs and they seem to read fine; i compared them against a chart of what good, healthy plugs should look like vs. warning sign plugs. i've tried solving this problem in the past by running a larger secondary nozzle, but no dice. i stepped up the secondary jets 1 size up.. but still no dice, and the plugs started showing signs of richness. afterwards, i thought it was because i was running 87 octane. however, i remembered this happening as well even when i ran 93 regularly. i'm thinking it might be ignition, but i don't have any experience with ignition systems, and i don't have the troubleshooting experience to know where else to look other than what's above. do you guys have any suggestions what i should be looking for/trying next? opinions? |
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#2
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Gerard wrote: > > do you guys have any suggestions what i should be looking for/trying > next? opinions? Check the ignition advance unit. If it's a vacuum advance, replace the hose and see if that fixes it. George Patterson A man who carries a cat by the tail learns something that cannot be learned any other way. Samuel Clemens |
#3
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"G.R. Patterson III" > wrote in message >...
> Gerard wrote: > > > > do you guys have any suggestions what i should be looking for/trying > > next? opinions? > > Check the ignition advance unit. If it's a vacuum advance, replace the hose > and see if that fixes it. > > George Patterson > A man who carries a cat by the tail learns something that cannot > be learned any other way. Samuel Clemens It's a worn cam lobe. The small-block Chevies had a real problem with that. The exhaust valve doesn't open much, and the pressure in the cylinder blows back into the intake manifold when the intake opens and burns the incoming charge, making a pop in the carb. Seen it several times. Dan |
#4
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now there's something i didn't consider... interesting. i'd believe it,
too, because i think my cam and lifters are on their way out. > > It's a worn cam lobe. The small-block Chevies had a real problem > with that. The exhaust valve doesn't open much, and the pressure in > the cylinder blows back into the intake manifold when the intake opens > and burns the incoming charge, making a pop in the carb. > Seen it several times. > > Dan |
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