Holley with SCV and Duraspark II ... working?

[Anonymous]

I had a interesting day today ... the Autolite 1101 I bought from eBay turned out to be some sort of Holley 1V (9510?) ...

It has an SCV which I didn't want ...

While trying to figure out a solution to the problem I hooked up the timing light to see what effects different vacuum hookups had on the timing. What I found out was the the mechanical advance on my Duraspark dizzy wasn't working ... no matter what I revved the engine to ... the timing never changed. So I hooked up the vacuum advance to the SCV vacuum port and and engine advanced properly.

1) What would cause the mechanical advance not to work in a Duraspark II but the vacuum advance works fine.

2) Does disabling the mechanical advance on the Duraspark II convert the dizzy into an SCV compatible version?

I haven't been able to road test yet but parked in my garage and using a timing light shows all is working well with the Duraspark II hooked up to the SCV vacuum ...

Dan

 

[CZLN6]

Howdy Back:

"the Autolite 1101 I bought from eBay turned out to be some sort of Holley 1V (9510?) ... It has an SCV which I didn't want ... "

Bummers!! Do you know What year? Application?

"1) What would cause the mechanical advance not to work in a Duraspark II but the vacuum advance works fine. "

A- Something is stuck on the advance mechinism. There are 2 strings, 2 counter weights and corresponding pivot points and the advance plate. If anything is stuck the advance will not operate. Disasemble and clean.

"2) Does disabling the mechanical advance on the Duraspark II convert the dizzy into an SCV compatible version?"

Disabling the mechanical advance has nothing to do with the vacuum advance function.

But, will the SCV system work on a non-load-a-matic distributor? Yes, Somewhat. The SCV in that carb is designed to send a specific vacuum signal for that carb on the engine, vehicle and trans. It goes to a corresponding vacuum cannister on a Load-a-matic distributor, again, unique to application. If your engine and vehicle conditions are similiar to the carbs intended application, and if your DS II vacuum cannister has similar characteristic to intended application, it should work similiar. Do you feel lucky? Well, do you????

You should never use a SCV vacuum signal with a working mechanical advance distributor. It would be a very confused spark curve.

Ultimately, you will want a coordinated package. Fix the mechanical advance. Mechanical advance is for performance, Vacuum advance is for economy. You will want both and a carb with a ported vacuum signal for the DS II.

Good luck.

Adios, David

 

[Anonymous]

I'm gonna replace the carb with an RBS for a 1970 250 Maverick ... the air cleaner mount is the same or similar to the Autolite and Holley so it should work with the air cleaner I have ...

Once I have the new carb I'll fix the Dizzy as well and then have a matching set ....

Thanks for the info ...