Confessions of a novice, shady tree mechanic...

[livinginthepast]

So I think I'm starting to get it. But I'm still not sure.

As some may recall, I battled to get the carbs on my BE tuned after bringing the car home last summer. Eventually (after rebuilding the carbs and installing oversized throttle shafts, I got them tuned to what I thought was reasonably well (maybe a little rich) and the car has been running okay (except the most recent generator failure <sigh>).

So today, I started tinkering with the ignition (I had a care package arrive in the mail yesterday!). New plugs. New plug wires. New coil. New points. Adjusted. Dwell is off. Dbl then trpl checked. Dwell still off. Weird. I disconnected and plugged the vacuum line, put a timing light on it. Hmmm.. Timing shows straight up TDC, s/b something like 6 degrees btdc (or was it 4 - doesn't matter now I guess). So I adjust the timing and now the fuel isn't burning efficiently (lots of exhaust on acceleration). But I check the dwell again and it's improved???

So, now I'm reasonably sure the ignition is set up correctly, which brings me full circle back again to my original nemesis: the carbs.

Now, I've read over and over again that the carbs are the last thing that should be touched in a tune up. Guess I found out why. Ugh.

Given what I've just described, can you tell me whether I'm finally on the right track?

 

[spritenut]

The distributor in general may be worn out.
There is a bushing inside which wears making setting the dwell impossible.
Also 90% of carb problems are ignition related and 90% of ignition problems are fuel related :wink:
Timing marks on the harmonic balancers that are 40-50 years old will never read correct because the rubber inside them lets them slip by 10 degrees or so.
The Bugeye if it has a 948 would have the stamped steel pulley but a 1275 with an old pulley will not read correct.
Check the distributor shaft for any wobble from side to side.
Remove if from the car, spin it counter clockwise by hand and listen for the advance weights to move or twist the rotor while holding the bottom drive to see if it moves freely. Stuck advance weights will kill your timing too.
Now wiggle the shaft side to side, if it's tight, the bushing should be OK.
New bushings are available from Peter at World Wide Auto (the shock man) and a disassemble, cleaning, and oil in the advance weight system under the points plate is due if it's hasn't been done in 50 years.

 

[DrEntropy]

Additionally, the advance plate can wear at the collar contact point (where the top plate rotates on the bottom piece) and chew itself to the point of disintegration. The advance is then erratic.

 

[livinginthepast]

Thanks - I was actually thinking that the distributor may be playing a role in this as I am seeing a slight jumping of the timing notch (this is a 948 btw) under the light. I wasn't sure how much of this is normal, however. I do have a known good distributor that I can drop in, so maybe that will be my Saturday project!