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May 4, 2000 | 02:55 PM

chilly460

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Joined: Jan 2000

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Distributor question

I run a 351w that has a duraspark type distributor in it. I can't run the vacuum advance because it pulls more than 40 degrees of advance with it hooked up, and that's with initial set at 6 degrees! Also, the vacuum advance is adjustable, it's set to give the lowest amount of advance. I've verified that the timing marks are correct. I've done some research and know that these distributors are kind of screwy because they were designed for to work with all the emmissions crap that played with the timing. Is there any way to remedy this or should I start looking for a new distributor?

May 4, 2000 | 05:28 PM

Post Fiend

Joined: Feb 2000

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From: Brea CA

Distributor question

Chilly,
If I remember correctly, turning the allen screw counter-clockwise puts more preload on the vacuum advance spring and slows down the timing. Do you have yours turned all the way CCW? If so, you might want to try an advance unit out of a late ‘60s / early ‘70s distributor. They are constructed a little differently where instead of just being able to adjust the spring tension for the rate, you can also adjust the total advance limit. You can identify this unit by the combination hex nut and nipple that unscrews (sounds nasty!) The rate is adjusted by the spring pressure and spacers while the limit is controlled by the length of the tube inside. You can add spacers or stretch the spring for a new rate and cut some regular copper tubing to make a custom length replacement rod for the limit. BTW, are you running ported vacuum or manifold vacuum?

May 4, 2000 | 06:45 PM

chilly460

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Distributor question

Thanks for the suggestion, that makes sense to use an advance from a pre-emmissions engine. I tried using both ported and manifold vacuum, they both pull too much advance. I did turn it CCW after reading an article in Car Craft, that's what I was referring to about setting it to the slowest. One more question: Can you get a new vacuum advance like you're referring to from a basic parts place like Autozone?

May 4, 2000 | 06:49 PM

Nathan

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Joined: Aug 1999

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Distributor question

fI have noticed that not many people are happy with the Duraspark ignitions. I personally have not tried any aftermarket distributers or ignition controls, but I have heard that this is a super upgrade to an already good Ford motor. You might want to just bite the bullet and invest in an ignition system like a MSD-6A, coil and distributer and maybe kill two birds with one stone. Just a thought!

Nathan

May 4, 2000 | 08:49 PM

chilly460

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Distributor question

I have an MSD6a box and coil so maybe its not a bad idea to go ahead and step up to the distributor. Problem is, I have a '76 f250 and I just got done rebuilding the 390 so cash is a little tight, a new Mallory distributor is $200 and an MSD is more.

May 4, 2000 | 08:59 PM

jbhf250

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Joined: Oct 1999

Posts: 917

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From: Kelseyville USA

Distributor question

Crane has a vacuum advance that is adjustable.and will go from ZERO to 30 . mine will... about 15.00 if i remember.
Look at the numbers on the Machanism in the distributor rotator section mine was 13 and 18 which translated to 26deg and 36 deg of advance!!
I put a piece of vacuum tubing over the DEAD STOP for the weights to bring it down to 10 MAX.
Now I can control the vacuum advance Maxium!!

__JOHN__Õ¿ö
72 F-250
ICQ#6030753
http://clubs.excite.com/72FORD-F-250

May 5, 2000 | 08:52 AM

Post Fiend

Joined: Feb 2000

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From: Brea CA

Distributor question

Chilly, the last time I bought one of those older vacuum advance units new was around 5 years ago at a NAPA parts dealer. You can also find them in the wrecking yards but make sure the diaphragm is not ruptured. Just my opinion, if you already have an MSD6a box and coil, I would seriously consider buying the distributor too, it’s a BIG step up from the Durafart system plus it won’t leave you stranded someday. I run a Unilite on my truck and am very pleased with it, just set it and forget it! I understand the money issue but IMHO, a superior ignition system is one of the most satisfying upgrades you can make as far as performance, mileage and dependability are concerned.