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Vacuum advance question for 35 40series


Buick35

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I decided to clean and rebuild the carburetor on my 35 which is a Stromberg down draft.Any way when removing the old base gasket next to the carb. I noticed that it completely blocked off the fitting going to the distributor for vacuum advance.I don't know how long it's been that way,at least 50 years since I owned it. It didn't seem to run too bad.I just thought that's the way the old gal run. I drilled a hole in my base plate adapter so the line would hopefully get vacuum.Curious to see if that makes any difference.Greg

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It will make a difference….if your distributor is stock. It’s very possible it is not. 

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Check your vacuum advance diaphragm.  Use a hand-held vacuum pump and verify (1) that it holds vacuum and (2) that the breaker plate moves freely without binding.  While you're at it, make sure that the braided ground jumper is in place between the breaker plate and distributor body.

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21 minutes ago, EmTee said:

Check your vacuum advance diaphragm.  Use a hand-held vacuum pump and verify (1) that it holds vacuum and (2) that the breaker plate moves freely without binding.  While you're at it, make sure that the braided ground jumper is in place between the breaker plate and distributor body.

Good idea.My distributor looks stock

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Posted (edited)
2 hours ago, EmTee said:

I replaced the leaky vacuum advance diaphragm on my '38 Century with a rebuilt one from Bob's Automobilia.

It's strange that the carb.gaskets I see pictured at Bob's doesn't have a hole in them for the vacuum advance,maybe the hole on the carburetor bottom is supposed to be blocked. 

Edited by Buick35
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I don't know about the carburetor on your car, but the ones I've seen typically the vacuum port sources vacuum through passages in the carburetor body or throttle body above the manifold gasket.  Maybe @carbking can comment about the Stromberg on your '35 Buick.

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This^^

It should go to a port inside the barrel that is just above the throttle plate at idle, and just below it as soon as you crack the throttle.

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Thanks,I'll look again but on mine if I blow air through the fitting for the vacuum line at the base of the carb. air comes out of the hole that was blocked off from the gasket,if that makes sense.

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I shot carburetor cleaner through the fitting and saw where the hole is above the throttle plate.There are two very small holes below the throttle plate,one in each barrel that might be plugged up. Maybe the hole under the gasket was just a machining hole.Thanks.

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I suggest you consider taking off the distributor plate and checking that your centrifugal weights are clean and free in movement. My son and I took ours apart and found that someone had put grease under them for lubrication, but the grease dried out and they would hardly move at all. One of the balls that kept the plate centered in the distributor also kept sliding out of place, which also kept the advance system from functioning properly.  We replaced our plate with one that has several ball bearings integrated into the plate, (thanks to Jolly John), and there is a remarkable improvement in performance. Our vacuum advance unit also leaked and would not hold while vacuum was applied. Had to replace that too.  Our car is a 40’ Buick Business Coupe, I would think your distributor would be functionally about the same. I hope this is helpful for you.  Bill

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2 hours ago, Bill White said:

I suggest you consider taking off the distributor plate and checking that your centrifugal weights are clean and free in movement. My son and I took ours apart and found that someone had put grease under them for lubrication, but the grease dried out and they would hardly move at all. One of the balls that kept the plate centered in the distributor also kept sliding out of place, which also kept the advance system from functioning properly.  We replaced our plate with one that has several ball bearings integrated into the plate, (thanks to Jolly John), and there is a remarkable improvement in performance. Our vacuum advance unit also leaked and would not hold while vacuum was applied. Had to replace that too.  Our car is a 40’ Buick Business Coupe, I would think your distributor would be functionally about the same. I hope this is helpful for you.  Bill

Thanks for the advice.

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I posted a step-by-step distributor rebuild a while ago.  It does make a difference when everything in there is functioning properly.

 

 

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