383 timing trouble
10-09-2007, 12:52 PM
#1
383 timing trouble a buddy of mine has a 383 with a complete msd ignition - pro billet distributor, digital 6 box and hvc coil. he just did a cam swap and had it on the dyno yesterday to get the air/fuel checked and make a couple nitrous pulls.
they checked the timing before making the bottle pulls and it right at 34* at 3500 rpm. then they revved it to 4000 and the timing started bouncing all over the place (back to 34 to 40 to 37 to 42 etc) without changing rpm from 4000. the distributor was tight and nothing was changed.
any idea what this could be? it was suggested it could be the distributor gear, but we didn't get to pull the distributor. anyone else seen this before? any ideas?
they checked the timing before making the bottle pulls and it right at 34* at 3500 rpm. then they revved it to 4000 and the timing started bouncing all over the place (back to 34 to 40 to 37 to 42 etc) without changing rpm from 4000. the distributor was tight and nothing was changed.
any idea what this could be? it was suggested it could be the distributor gear, but we didn't get to pull the distributor. anyone else seen this before? any ideas?
10-10-2007, 10:48 AM
#2
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is he running the mechanical advance or does he have it locked out? also the timing chain "moves" a little bit at higher rpms. if it gets to be a problem,lock out the mechanical advance and put a crank trigger on it and it will be gone
10-10-2007, 11:13 AM
#3
mechanical advance. i guess he pulled the distributor last night and the gear didn't look that good after all.
now that i think about it, he's got the timing cover on there with the adjustable button installed in it....you just turn it in or out from the outside of the cover. anyone ever used one of those, you think it could be allowing the chain to move around a little too much?
now that i think about it, he's got the timing cover on there with the adjustable button installed in it....you just turn it in or out from the outside of the cover. anyone ever used one of those, you think it could be allowing the chain to move around a little too much?
10-10-2007, 11:43 AM
#4
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mechanical advance. i guess he pulled the distributor last night and the gear didn't look that good after all.
now that i think about it, he's got the timing cover on there with the adjustable button installed in it....you just turn it in or out from the outside of the cover. anyone ever used one of those, you think it could be allowing the chain to move around a little too much?
now that i think about it, he's got the timing cover on there with the adjustable button installed in it....you just turn it in or out from the outside of the cover. anyone ever used one of those, you think it could be allowing the chain to move around a little too much?
10-10-2007, 11:47 AM
#5
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We have seen that before on some Snap on type timing lights, At our shop and the customers that run our engines we have them use the timing light from Flame River thats a one wire timing light, Make sure the balancer is degreed.
Most timing lights are made for setting the timing at idle.
Most timing lights are made for setting the timing at idle.
