Vacuum advance dist. for Model A

[Phil Brown]

Originally Posted by Hitman

I wouldn’t bring the 009 into this discussion

I didn't, try rereading post #1

[Dodge]

I'm using a Rover 4cyl. dist. with vacuum advance. You can get them with points or
electronic ignition. Easy conversion.
Carburetor is one of the new Stromberg 97's with a vacuum port.

[Gene F]

Originally Posted by Dodge

I'm using a Rover 4cyl. dist. with vacuum advance. You can get them with points or
electronic ignition. Easy conversion.
Carburetor is one of the new Stromberg 97's with a vacuum port.

Isn't that a downdraft, with 3 mounting holes to the manifold? Where did you get that?

[Dodge]

Summit Racing

[Synchro909]

I've been running a modified Nissan distributor on my Burtz engine and love it. It was done by "Performance Ignition" in Nunawading, Melbourne. I have used them before and been impressed each time. A bonus for you guys is that the exchange rate works FOR you but unfortunately, AGAINST us.

[Will N]

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I never understood the need for vacuum advance until I researched it yesterday after seeing this thread. I always figured an engine develops its highest vacuum when the throttle is closed or slightly opened, and wouldn't need advance under these conditions. But I read that when cruising at a steady speed and only a little load, the throttle is only partly opened, increasing vacuum, and also the fuel/air charge going into the cylinders is restricted by the throttle. This less dense charge of fuel/air takes more time to burn because, well, it's less dense. And because it takes longer to burn you need the spark to occur earlier. Fascinating.

[AzBob]

Retard no.3 cylinder for cooling? Perhaps air cooled VW engines behave differently than a Model A engine. When I retard my Model A engine, it runs hotter. What am I missing?

[nkaminar]

Arizona Bob. I think it is a matter of degree. Two or three degrees may make the engine run cooler, especially on a higher compression engine. That is one notch on the ignition lever on a Model A. The very slightly retarded ignition means that cylinder is not producing as much power and will run cooler by a few degrees. This is all guess work on my account. I am trying to put myself in the mind of the VW engineers.

[AzBob]

Originally Posted by nkaminar

Arizona Bob. I think it is a matter of degree. Two or three degrees may make the engine run cooler, especially on a higher compression engine. That is one notch on the ignition lever on a Model A. The very slightly retarded ignition means that cylinder is not producing as much power and will run cooler by a few degrees. This is all guess work on my account. I am trying to put myself in the mind of the VW engineers.

Thanks nkaminar. Sounds plausible. This now makes sense to me considering the slightly retarded no. 3 cylinder will make a little less power and thus run cooler by a few degrees.

[nkaminar]

Modern cars, of course, have a computer and bunch of sensors to control ignition timing. The Model A in stock form relied on the operator to control the ignition timing. In my case this is just fine as I have gotten used to using the ignition lever over the last 60 years of driving Model A's.

[Tanglfoot]

Hello all, I am with Synchro 909. I have used Nissan Navara Distributors from around 1990 with good results. They are easy to adapt and parts still available here. Cheers Rosco

[Bruce of MN]

I see that Nissan is a light pickup. At https://www.rockauto.com/en/catalog/...stributor,7108

it shows Mitsubishi and Hitachi types, which one is preferable? (I see one is out of stock)

[AzBob]

Originally Posted by Bruce of MN

I see that Nissan is a light pickup. At https://www.rockauto.com/en/catalog/...stributor,7108

it shows Mitsubishi and Hitachi types, which one is preferable? (I see one is out of stock)

I don't see a vacuum control canister on any of those Nissan distributors.

If you want points ignition you are going to have to go earlier than 1980. Prices for the Honda Civic distributors used to be in the $25 to $100. range.

Perhaps Tanglfoot or Synchro 909 can post a picture of their setup.

[nkaminar]

Can you stick that vacuum actuator that Arizona Bob posted on the ignition advance lever?

[Dave in MN]

I have modified a couple Lucas 25D vacuum/mechanical advance distributors for use on high compression heads. I need three more for engine builds in the works. I get them on Amazon for about $80.00. The lower part of the distributor needs to be machined so it fits the Model A distributor hole.

I ran one on my round trip roadtrip which included touring Alaska last summer without issue. The entire trip was 11,500 miles.

When I modify the next three distributors, I will add some photos to my post.
Good Day!

[loud41]

Originally Posted by Dave in MN

I have modified a couple Lucas 25D vacuum/mechanical advance distributors for use on high compression heads. I need three more for engine builds in the works. I get them on Amazon for about $80.00. The lower part of the distributor needs to be machined so it fits the Model A distributor hole.

I ran one on my round trip roadtrip which included touring Alaska last summer without issue. The entire trip was 11,500 miles.

When I modify the next three distributors, I will add some photos to my post.
Good Day!

I'd love to see what you ended up doing to get those Lucas distributors to fit!

[Bruce of MN]

Are VW Beetle distributors suitable for modification?

[Dave in MN]

Originally Posted by Dave in MN

I have modified a couple Lucas 25D vacuum/mechanical advance distributors for use on high compression heads. I need three more for engine builds in the works. I get them on Amazon for about $80.00. The lower part of the distributor needs to be machined so it fits the Model A distributor hole.

I ran one on my round trip roadtrip which included touring Alaska last summer without issue. The entire trip was 11,500 miles.

When I modify the next three distributors, I will add some photos to my post.
Good Day!

The vacuum supplied to retard the timing is taken from the base of the air filter. The primary function of the timing advance is from the centrifugal advance weights. The system works very well. I have used it for about 15,000 miles over the past two years.

See photos attached…..

[40 Deluxe]

Originally Posted by mcgarrett

Is anyone making or modifying a distributor for Model A engines that incorporate vacuum advance? I know about the Rex-a-co centrifugal advance unit, but it's not vacuum controlled. Has anyone ever modified a distributor like the Bosch 009 for example that would work well in the Model A engine? Would there be any benefit especially when running high compression heads?

The Bosch 009 is a centrifugal advance only, as I recall. Other older Bug distributors were vacuum advance only, like a Ford Load-A-Matic.

[Bob Bidonde]

Find a centrifugal advance distributor instead. The vacuum drops of the Model A engine are extreme. I can imagine what the effect of running the vacuum wiper will be on a vacuum advance system.