Distributor Propblem?

[Road Grabber]

I think I might have a distributor problem. I have tracked down other vacuum leaks, switched to a restored carb and still have some hesitation/lack of response.

I saw another ;post that ended up with a vacuum advance problem. I am thinking maybe I have a vacuum advance leak problem.

I'd like to remove the vacuum advance from the system and go mechanical advance. Is there a way to make a vacuum advance distributor into mechanical advance?

I have a mechanical advance setup in another car. Had the distributor setup for initial 14 advance and total 34? It works great. I am thinking of doing to the same thing by changing the dual point I have now into a mechanical advance setup.

Any thoughts? Ways to check the existing distributor?

I used to know where to take the distributors to have them diagnosed and checked but those guys are no longer around.

Thank you

 

[threewood]

To check the vacuum advance for a leak, unplug the vacuum hose from the carb and attach to a vacuum pump and see if it leaks down. Another way to test is to suck on the hose and stick it to your tongue. If it loses suction and unsticks it is leaking (poor mans method which I use lol).

Your distributor has a mechanical advance already installed so if you truly want to unhook the vacuum advance just unhook the vacuum hose, leave the vacuum advance canister attached otherwise the advance plates inside would need to be secured.

Also, check your dual point gap and dwell. Get it within spec before moving on to something else.

 

[Road Grabber]

To check the vacuum advance for a leak, unplug the vacuum hose from the carb and attach to a vacuum pump and see if it leaks down. Another way to test is to suck on the hose and stick it to your tongue. If it loses suction and unsticks it is leaking (poor mans method which I use lol).

Your distributor has a mechanical advance already installed so if you truly want to unhook the vacuum advance just unhook the vacuum hose, leave the vacuum advance canister attached otherwise the advance plates inside would need to be secured.

Also, check your dual point gap and dwell. Get it within spec before moving on to something else.

Thanks for the reply

If I disconnect the vacuum advance would I increase the initial timing?

Would you place a lighter spring inside on the advance weight?

 

[threewood]

It depends on where it is connected to the carb. Above the throttle plates is ported = no vacuum at idle so no change in initial. If it is connected below the plates = manifold vacuum so if you disconnected it it would retard the timing. You would have to adjust curb idle back up unless it was tuned with it unhooked.

As far as springs, the usual modification is to remove the stock heavy spring and add in a lighter on. You need to check advance and total with your timing light as you rev it up to see how soon it comes in. Some cars can ping if it gets too much too soon.

 

[Road Grabber]

It depends on where it is connected to the carb. Above the throttle plates is ported = no vacuum at idle so no change in initial. If it is connected below the plates = manifold vacuum so if you disconnected it it would retard the timing. You would have to adjust curb idle back up unless it was tuned with it unhooked.

As far as springs, the usual modification is to remove the stock heavy spring and add in a lighter on. You need to check advance and total with your timing light as you rev it up to see how soon it comes in. Some cars can ping if it gets too much too soon.

When I disconnect the vacuum line it has no effect on timing. I’ll try the light spring

 

[AR67GTX]

Your vacuum advance is apparently hooked up to ported vacuum which only produces vacuum when the throttle blade is opened and increased air flow in the Venturi begins to generate a vacuum signal. Basically the vacuum advance will only functions when the throttle is partly open and being held steady (not accelerating). Basically a steady cruise speed. Thus at idle it does not affect timing.

 

[Road Grabber]

Got it thanks

 

[Road Grabber]

So I disconnect the distributor advance hose begin to suck and low and behold the diaphragm must be shot. I can blow through and suck through without resistance.

Can diaphragms bring repaired? Do you think they sell replacements? Just do I can fix the distributor.

Thank you for the backyard test.

 

[68 Sport Satellite]

They sell hex head mopar adjustable vacuum advance canisters separate (don't know about the diaphragm by itself)

 

[AR67GTX]

Not worth repairing (if even possible). Check with Halifaxhops - he probably has the correct one for your car.

 

[Road Grabber]

This is the diaphragm. I have to see if the distributor has the part number on it.

The engine already runs better since I removed the hose and plugged the carb.

 

[threewood]

@HALIFAXHOPS Can you see what he has from the picture above?

 

[HALIFAXHOPS]

Looks like a dual point what is the number on it and application?

 

[Road Grabber]

It is a dual point. Not sure if it’s the original one for the car but it is in a 1970 383

 

[HALIFAXHOPS]

I have them rebuilt. $80 and a core I need. No rubber neopream inside.

 

[Road Grabber]

I have them rebuilt. $80 and a core I need. No rubber neopream inside.

I hate to ask but are they tested before shipping?

 

[HALIFAXHOPS]

Yes. Yo hace o change over the nipple with the springs and spacers beghind it. If I get the core first I can do it for you no issues.

 

[HALIFAXHOPS]

Just some random pics of them

 

[Road Grabber]

This is the number off the distributor

2875847

If I remove it can I put the distributor back in the car and use the engine? It’s not working now anyway.

It should be ok correct?

 

[Road Grabber]

This is the number off the distributor

2875847

If I remove it can I put the distributor back in the car and use the engine? It’s not working now anyway.

It should be ok correct?

Where do I send it and can I have contact information?