vacuum advance question on my stock 318

Uncle Don · Jun 3, 2010

stock 318 poly, 66 model 2bbl. i put new points, plugs in and it was running like poop...would idle fine and then wouldn't rev up for nothin... stalled out, like it was being choked down etc...so i went home at lunch today, unhooked my vacuum advance hose from my carb to the dist, blocked off both..and wallah:grin: it runs like a champ....i can even goose it driving around the neighborhood with little or no hesitation...what gives???? any you gurus know whats up??? do i need a new little vacuum pod thingy on my dist? its a stock dist and im assuming no curve kit or anything like that...

66 coronet · Jun 3, 2010

Sounds like the diaphram in your vacum advance is ruptured giving you a vacum leak when its connected.

khryslerkid · Jun 3, 2010

66 coronet said:
Sounds like the diaphram in your vacum advance is ruptured giving you a vacum leak when its connected.

:yes:

Uncle Don · Jun 7, 2010

nope didnt fix it. put new one on and same thing...car has new points, new plugs, new vacuum advance...and still runs like pooppoo with vacuum advance hooked up. i wonder if it advances it too much, does anyone know how many degrees it will advance when rev'd up?

66 coronet · Jun 14, 2010

Did you check your timing??? When i got mine it would start and run good when cold, when hot it would stumble and try to die out. the timing was set about 30 deg. retarded. Set your timing with the vac unpluged and the hose capped, when you reconnect the vac your timing will advance to around 30 deg. this is what its supposed to do, it will only do this at high vac condition like idle.

mguner · Jun 14, 2010

As far as I know most all Mopar vacuum advance is set to run off of ported not manifold vacuum. That is not to say manifold won't work since that is how the bow ties do it. What may be happening is a problem with the braker plate when the vacuum pod pulls on it causing your dwell and point gap to go out of spec. Rebuilt distributors are fairly cheap as in only about $10 more than the vacuum pod probably cost..... Just a thought. Mopars like as much initial timing as you can give them without being hard to start hot or pinging under load. From this point shorten the curve to about 34-36 total mechanical and then not more than 50 total with vacuum.

Uncle Don · Jun 15, 2010

66 coronet said:
Did you check your timing??? When i got mine it would start and run good when cold, when hot it would stumble and try to die out. the timing was set about 30 deg. retarded. Set your timing with the vac unpluged and the hose capped, when you reconnect the vac your timing will advance to around 30 deg. this is what its supposed to do, it will only do this at high vac condition like idle.

ok we may be on to something then... because at idle with a timing light on it, vacuum unhooked and capped off i get 10 degrees. now when i hook the vacuum advance back up i still only get 10 degrees at idle...it doesn't make a difference whether i have it hooked up or not at idle...now when i rev it up i can tell a difference, thats when it stumbles and stutters with it hooked up.....do i need to just go and buy a new dizzy electronic and change it over and be done??

rumblefish360 · Jun 15, 2010

FWIW, I just purchased a whole kit from Summit racing for $166 bucks, electronic distrib, box, ballast and harranass like the MoPar kit. They may still be on sale..... Just food for thought...

sleepar · Mar 13, 2014

Keep the points, just learn them..there is a tiny 9/32" Allen screw in the hole of the vac. Adv on the distributor... this adjusts the total vac. advance a turn will make a big difference better or worse till you dial it in. Just be careful not to puncture the diaphragm... you have to feel around for it like on a first date

Meep-Meep · Mar 13, 2014

I had a similar issue with an electronic long ago and at the time just left the vac advance off. But now I look back and suspect it might have been a rotor phasing issue. Get a new distributor cap and make the current one into a checking fixture. Drill a hole in the old cap by any tower so you can see the rotor. Connect the timing light pickup to the wire on the drilled tower, start it up and point the timing light in the hole and you should see the rotor appear near #1. Rev it up until it misses and I bet you will see the rotor somewhere else or disappear trying to arc to the next tower over. To fix this you can move the breaker plate around but would have to know which direction. Or just get a rebuilt distributor and hope it's aligned properly. With vac advance the rotor tip will not be perfectly lined up with the tower but a little advanced because there must be enough room to allow the breaker plate to sweep across and still have the rotor arc at the correct terminal. I'm pretty sure this is what's going on.

vacuum advance question on my stock 318

Uncle Don

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66 coronet

Well-Known Member

khryslerkid

FBBO Gold Member

Uncle Don

Well-Known Member

66 coronet

Well-Known Member

mguner

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Uncle Don

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rumblefish360

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sleepar

Well-Known Member

Meep-Meep

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