done with the dizzy dizy

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40's rock

Feb 5, 2006
After much examination and fire out the exhaust, I have come to the conclusion that the vacum p/u on my dist is toast, it will never hold time.
I'm ready to change to something so I can actually drive my 40.....what do the great MUD GODS suggest? DUI?
side note...2f out of an 85 60 with a weber carb..desmogged
An '85 2F distributor is as good as it gets and it can be fixed for a lot less than the cost of a new one.

What makes you think that the distributor is at fault?
well......the engine was just swapped and the dist from the 85 wasnt complete, so randy installed the dist from my original 76 engine which was a replacement for the maf gm pos installed by po that broke a vac pu...found where it should have been, connected vac line, but it doesnt respond. I will set the timing, drives fine...then literally the next day it is way out of time...backfires on accel, just doesnt advance...I am open to other suggestions
the old one broke a gear? perhaps the gear on the cam itself has had it. I have seen cams that the GM distributor pretty much destroyed the cam gear.
the gear broke on the maf dist while in the the old lost compression, so we put in the 2f from an 85 60...the dist was swapped over from my old engine due to missing parts on the 85...Probably less than 15 hours in the "new engine" I would think that cam wear would be minimal at this point
Howdy! Is the base timing setting changing, or is it a problem with the advance controls? IIRC, baseline timing is set with NO vacuum connected. If this setting changes, then the clamp at the bottom of the body is not preventing it from rotating as the engine runs. Your current dizzy should have either or both a vacuum advance/retard diaphram with a hose or two hooked up to it, and a mechanical advance (centrifical wieghts) on the inside. You could have a vacuum leak or sticky weights, both cheap and easy to fix. Are you setting the timing with the engine warm? Are you sure that the choke is hooked up properly and fully operational, as that can create the performance/backfire problems. John
do you think I need to free up sticking weights in the dist? I dont know how to do that....
Sticking mechanical advance would definitely cause the random timing changes.
Howdy! It is certainly worth checking out. Jim, is it set up like an old Chevy? Those have the weights right under the distributor rotor. Remove the two screws, lift the rotor up, and it looks like 2 chicken wings hanging on little springs. Should be able to rotate the plate by hand and the weights should move in and out smoothly. A little WD-40 can free them up, and you can put JUST A LITTLE BIT of heavy grease on the pivot pins and the sliding surfaces. Some dizzies have this assembly under the base plate where the points are mounted. You can still grab the rotor and rotate it to feel if the weights move freely. If not, you can pull it apart to service it. John
John, the 75-later dissies are more modern. Weights & springs are way down inside the dissy.

But as you said, a good quick test is to twist the rotor in the advancing (CW) direction, see if it moves about 20-30*, then snaps back when released.
ok...plate snaps back when turned, shot wd-40 under plate...vacum advance is freed up and moves under suction....points don't looked burned...any other suggestions?
Howdy! Sounds like your making good progress by eliminating one thing at a time. Backtrack you vacuum supply. If your are stock OEM, it should be vacuum retard. My memory is a bit foggy, as my 76 hasn't been stock for over a dozen years. Regardless, the dizzy hose should go back to the ugly little box on the driver's side fenderwell. It's got a bunch of hoses to it. That's the VSV (vacuum switching valve). They all need to be hooked up right or blocked off if your are desmogged. IIRC, to test the vacuum at the dizzy, get the engine up to running temp. With engine at idle speed, pull hose off of retard diaphram and put finger over the end of the hose. Rev engine up to 2500 - 3000 rpm and let off the gas. You should feel vacuum as it slows down. I don't think there should be any vacuum at idle speed. Silly question, are you still running the original carb? John
last update tonite....after the above metioned repairs...and a wrestling match with a previously good dist is running like a champ...I can even feel the secondary kick in on the weber...thats never happened before. Slight dieseling when turning off the engine, but i will blame that on the idle speed set too high.
I will let it cool overnite and see if we have the same success tomorrow. Thanks everyone for the help!!
well...she held time and runs like a bat...Thanks again to everyone!!! Now if I could just run down the dieseling issue....tried 93 octane and now running 87...isnt quite as bad.
well...she held time and runs like a bat...Thanks again to everyone!!! Now if I could just run down the dieseling issue....tried 93 octane and now running 87...isnt quite as bad.
Howdy! Glad it's working better for you. The factory carb had an idle fuel cutoff solinoid to prevent the dieseling. The Webber doesn't have that, so it may be impossible to completely stop it. John

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