Timed vac port or Manifold port??

[Stanglover]

To save me time searching past posts, can someone tell me for sure whether I should use the timed vacuum port on the Holley carb, or the full manifold vacuum port for the vacuum advance on the original Ford distributor, which is being recurved. My instructions sheet for the carb says to use the timed port, but I recall reading that it should be the full vacuum port I should use. I don't need to get into a drawn out long thread here, but if I can get a quick for sure answer, that will be appreciated.

Thanks,

Geoff.

 

[barnett468]

Use the timed/ported port for single vacuum cans . I set the vacuum can to add only 5 - 6 degrees when I recurve distributors because when they are done properly, much more than that is too much.

If you do not have an adjustable vacuum can you will likely need one because the non adjustable ones I have seen all add at least 10 degrees of advance and sometimes more.

The numbers for adjustable cans for that distributor are:

STANDARD MOTORS PRODUCTS .......... VC31

BORG WARNER .................................. V311

.

 

[Stanglover]

Use the timed/ported port for single vacuum cans . I set the vacuum can to add only 5 - 6 degrees when I recurve distributors because when they are done properly, much more than that is too much.

If you do not have an adjustable vacuum can you will likely need one because the non adjustable ones I have seen all add at least 10 degrees of advance and sometimes more.

The numbers for adjustable cans for that distributor are:

STANDARD MOTORS PRODUCTS .......... VC31

BORG WARNER .................................. V311

.

Thanks Barnett, That's what I needed and what I thought it should be.

My distributor has adjustable vacuum, so I will tell my 'guy' to set it as you describe,

I appreciate your response,

Geoff.

Use the timed/ported port for single vacuum cans . I set the vacuum can to add only 5 - 6 degrees when I recurve distributors because when they are done properly, much more than that is too much.

If you do not have an adjustable vacuum can you will likely need one because the non adjustable ones I have seen all add at least 10 degrees of advance and sometimes more.

The numbers for adjustable cans for that distributor are:

STANDARD MOTORS PRODUCTS .......... VC31

BORG WARNER .................................. V311

.

One more thought, Mine is dual vacuum. I should block off the retard side as it really is not needed and just use the advance side. Yes / no?

 

[barnett468]

.

Yes you can disconnect the manifold vacuum to the retard port and use the can for advance only providing you can reduce the amount of advance it adds to 5 - 6 degrees, however, I don't do that that because you are relying on two springs acting against each other to center the diaphragm to bring it back to zero advance instead of a positive stop when there is insufficient vacuum to engage it, therefore, there is a possibility for it to fluctuate some under some conditions.

Also, using a single diaphragm is just a much cleaner look and it is important to make your engine look stylish whenever possible.

 

[Stanglover]

.

Yes you can disconnect the manifold vacuum to the retard port and use the can for advance only providing you can reduce the amount of advance it adds to 5 - 6 degrees, however, I don't do that that because you are relying on two springs acting against each other to center the diaphragm to bring it back to zero advance instead of a positive stop when there is insufficient vacuum to engage it, therefore, there is a possibility for it to fluctuate some under some conditions.

Also, using a single diaphragm is just a much cleaner look and it is important to make your engine look stylish whenever possible.

That makes perfect sense, so thank you for your time once again. I'll make sure it gets done right this time!!

Geoff.

 

[barnett468]

That makes perfect sense, so thank you for your time once again. I'll make sure it gets done right this time!!

Geoff.

No prob, glad I was useful.

The Borg Warner unit is typically much cheaper than the SMP is . They are both the same so either will work and any auto parts store can get one or the other . Summit racing also sells the SMP one.

Rock Auto is pretty much the cheapest place to get parts and you can order online and they will mail them.

 

[Stanglover]

That makes perfect sense, so thank you for your time once again. I'll make sure it gets done right this time!!

Geoff.

No prob, glad I was useful.

The Borg Warner unit is typically much cheaper than the SMP is . They are both the same so either will work and any auto parts store can get one or the other . Summit racing also sells the SMP one.

Rock Auto is pretty much the cheapest place to get parts and you can order online and they will mail them.

I'll order one from Rock Auto if they have it. I just bought engine mounts (made in India!!!) and they gave me a discount coupon on my next order. I found it on SMP's website, but could not find it on Borg Warner's. The number didn't show a result, perhaps wrong number?

Anyway, thanks again.

Geoff.

 

[barnett468]

I'll order one from Rock Auto if they have it. I found it on SMP's website, but could not find it on Borg Warner's. The number didn't show a result, perhaps wrong number?

Anyway, thanks again.

Geoff.

I wouldn't do that to ya but the Borg Warner one might be harder to find . Oreillys has it but they want $30.00 for it . Rock may not have it any longer.

SMP VC31

http://www.summitracing.com/parts/smp-vc31

BWD V311

http://www.oreillyauto.com/site/c/search/Distributor+Vacuum+Advance/02818/C0334.oap?year=1965&make=Ford&model=Mustang&vi=1333381

http://shop.advanceautoparts.com/p/carquest-by-bwd-distributor-vacuum-advance-control-v311/20100536-P

 

[Stanglover]

I'll order one from Rock Auto if they have it. I found it on SMP's website, but could not find it on Borg Warner's. The number didn't show a result, perhaps wrong number?

Anyway, thanks again.

Geoff.

I wouldn't do that to ya but the Borg Warner one might be harder to find . Oreillys has it but they want $30.00 for it . Rock may not have it any longer.

SMP VC31

http://www.summitracing.com/parts/smp-vc31

BWD V311

http://www.oreillyauto.com/site/c/search/Distributor+Vacuum+Advance/02818/C0334.oap?year=1965&make=Ford&model=Mustang&vi=1333381

http://shop.advanceautoparts.com/p/carquest-by-bwd-distributor-vacuum-advance-control-v311/20100536-P

I ordered the SMP VC31 from Rock Auto for $24.50 CAN. Cheap enough even with 10 bucks shipping.

Again, thanks for your help on this.

Geoff.

 

[barnett468]

I ordered the SMP VC31 from Rock Auto for $24.50 CAN. Cheap enough even with 10 bucks shipping.

Again, thanks for your help on this.

Geoff.

No prob, you're very welcome.

FYI - Those particular advance cans use a small allen head screw for adjustment . All the way in [clockwise], is full advance . The farther out you turn it [counterclockwise], the less advance it adds.

Also, when you turn the screw, it causes the arm to move the timing plate slightly, so recheck your idle timing after adjusting the screw . I would start with the screw turned out 5 turns from fully in . This should get you fairly close to having it add 5 - 6 degrees of advance.