Quote:
Originally Posted by juanbenae
are you using the OE ignition box? carbs generally are going to need a hotter box & coil such as an MSD and blaster coil to generate enough spark. a recurved distributor is almost a must to get the advance the carbs like. also a worn distributor shaft will play havoc on a consistent timing effort.
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It is the original ignition box and coil.
Quote:
Originally Posted by pampadori
sounds to me like the carbs need to be balanced and idle stops adjusted (i know you said you already did that but maybe crack them all open a little more).
if one cyl is not open as much as the others at idle, then it won't fire the mixture.
If you think cyl 3 or 4 are the culprits, whichever of those two has the greatest vacuum at idle is the one I would start working with. make the vacuum at idle less for that cyl. You'll have to go back and adjust the other 5 afterwards to sync again.
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I've tried all kinds of different configurations as far as the initial settings but always end up at nearly the same settings after tuning the carbs.
Quote:
Originally Posted by OSC911
If I remember correctly the initial timing should be st at 5 deg after top dead centre. Sounds weird but I am pretty sure it is the setting on a 2.7.
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You are correct, but that is with the vacuum line attached which retards the timing. Since there is no vacuum line I have it set at about 5 degrees before, otherwise the mechanical advance would only advance to 20 degrees or so at higher RPM. I have tried to see how it idles at 5 degrees after and it hardly runs.
Next I'm going to try a new set of points. I pulled the distributor today to get a closer look and noticed that part of the points arm that wears against the distributor shaft is worn to the point where it only touches the shaft at max lift. So although the points gap is correct at full lift, it would be not be opening as long as it should be. My dwell measurement being in spec would contradict that, but then again my dwell meter was handed down to me from my father who bought it in the 70s at Sears. If new points don't solve the problem, maybe the MSD setup will be the next step.
Here's a picture of what I'm talking about with the gap between the distributor shaft and points arm:
