DISTRIBUTOR VACUUM DIAPHRAGM ID

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Aug 26, 2022 | 10:35 PM

Cougar2

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Mountain Pass

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DISTRIBUTOR VACUUM DIAPHRAGM ID

I just installed a 460 in my 79 F-350 4x4. The motor came from a 1976 Ford Econoline type RV. The motor has been totally rebuilt, but the timing is a problem. At this time, I can't put my initial timing passed 5 degrees since the vacuum advance is jumping it to just under 50 degrees. The adjustment on the diaphragm does not seem to work and I need to replace it. There is no casting numbers on it. The distributor is a Motorcraft 12127 and my question is, since I would like to find a Motorcraft part or at least comparable, I need a part number.

Is there anyone with a parts list to know what Motorcraft number should be used on the 12127 distributor for a 460? I don't want to buy a cheep off shore part if I can help it.

Aug 26, 2022 | 10:48 PM

tbear853

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From: The Shenandoah Valley

50 degrees with vacuum ain't bad, it retards when you step into the throttle, that how it works. You unplug vacuum and cap it to set timing anyway, then hook it back up for economical driving.

Aug 27, 2022 | 05:08 AM

mikeo0o0o0

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From: Stanley, VA

Plus, the part number you're using (12127) is just the basic P/N. All Ford distributors are p/n 12127. It's the prefix and the suffix that will ID a particular distributor.
The P/N should be something like D5TE-12127-AGA. That's a distributor for a 76-77 E250/350 w/ 460 and Cali emissions.

Aug 27, 2022 | 07:53 AM

Cougar2

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Mountain Pass

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Quote:

Originally Posted by tbear853

50 degrees with vacuum ain't bad, it retards when you step into the throttle, that how it works. You unplug vacuum and cap it to set timing anyway, then hook it back up for economical driving.

Possibly it's because I am using the timed port. When I used the manifold vacuum and bringing the RPM up "while setting up" it would start to stumble. It seemed to like the timed port more. The thing with this one is it's not responding to adjustment. Mechanical advance is normal, but as soon as I plug in the vacuum advance, it's dramatic. I will try it with the manifold port on the carb.

That said, I thought the way to check for total timing was to set initial timing, vacuum disconnected, then bring the RPM up to around 2000 and see the total from there. If this is incorrect, please fill me in.

Thanks for your response, I appreciate it very much!

Aug 27, 2022 | 06:32 PM

tbear853

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From: The Shenandoah Valley

Not wrong, but as I read it you were plugging in the vacuum while checking or setting timing. You might have a vacuum canister wsomeone has played with.