Vac advance on 24 volt dist

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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Johnny smith
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Vac advance on 24 volt dist

Post by Johnny smith » Sun Jun 17, 2018 2:35 pm

Can I block the vac line going to the orignal 24 volt dist !! do these have a vac control advance, or a weight advance like the MB?

cjv-35
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Re: Vac advance on 24 volt dist

Post by cjv-35 » Sun Jun 17, 2018 2:43 pm

Sure you are not confusing the vent line for a vac line ? M-38 distributors were waterproof mechanical advance units, not vac advance units.

Johnny smith
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Re: Vac advance on 24 volt dist

Post by Johnny smith » Sun Jun 17, 2018 3:04 pm

May be reading it wrong, looks like a vac line in the bottom and a vent line out the top not My flavor of jeep I do the earlier stuff, it runs good when I run the wipers and acts like a vac leak when they are off???

Johnny smith
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Re: Vac advance on 24 volt dist

Post by Johnny smith » Sun Jun 17, 2018 3:05 pm

May be reading it wrong, looks like a vac line in the bottom and a vent line out the top not My flavor of jeep I do the earlier stuff, it runs good when I run the wipers and acts like a vac leak when they are off???

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Re: Vac advance on 24 volt dist

Post by cjv-35 » Sun Jun 17, 2018 3:06 pm

Picture of the unit would be a big help.


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Re: Vac advance on 24 volt dist

Post by cjv-35 » Sun Jun 17, 2018 3:36 pm

I was confused. You are right. Two ports. Since the unit is mechanical advance, you can plug the vac line but plug the opening in the T were the vac line connects into on the intake manifold.

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Re: Vac advance on 24 volt dist

Post by Radtech » Sun Jun 17, 2018 3:48 pm

Both ports are for venting the distributor so the coil will not over heat.Without air flow through the distributor the coil will heat up and go bad.The vacuum line for the wipers comes from the vacuum pump on the fuel pump.

Johnny smith
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Re: Vac advance on 24 volt dist

Post by Johnny smith » Sun Jun 17, 2018 4:13 pm

Thanks Radtech, this thing has been monkeyed with so much its hard to tell whats what
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In ARK

mdainsd
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Re: Vac advance on 24 volt dist

Post by mdainsd » Mon Jun 18, 2018 10:08 am

The vent lines don't do much to cool the coil, notice how it is down in a well. Also very little air circulates through there as there is no forced ventilation. The fins on the housing are there to cool the coil.

However, those line must remain on and functioning. The remove ionized air which is conductive and to remove any condensation that might form in the distributor due to temp changes.

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