Vacuum advance questions?

Guys is there a way that I can increase timing on a motor to make up for the fact that I have non functioning vacuum advance.

I ordered one at least 7 days ago still not here and USPS cannot find it at the depot. Given the holiday I doubt I will see it for a week or more.

Depends greatly on what motor and what ignition setup

Basically, you need to know how much total advance the engine needs and what RPM it needs to be there by, plus have the balancer properly marked with that advance amount. You then run the engine at that speed with a timing light on it and turn the dizzy till the marks line up. That's how I had to set the ignition timing on my old 914.

With the vac advance not working, the initial advance is going to be greater. That means it's entirely possible it will be hard to start and could possibly have detonation under light loads, or even a big ol' flat spot low in the RPM range until the engine picks up enough RPM to get the advance weights moving.

IF... you have mechanical advance put heavier adv weights in then sort w/ light/ medium springs, they should advance timing quicker off idle but there still may be a flat spot

what car/ engine n e way?

fasted58 wrote: IF... you have mechanical advance put heavier adv weights in then sort w/ light/ medium springs, they should advance timing quicker off idle but there still may be a flat spot what car/ engine n e way?

Its the caddy, rebuilt 390 mildly build.

I effectively set the motor at total advance 3000 rpm and gun'd it to the gas station and back. It detonates like hell below 2000 rpm. Also it refuses to start when even the slightest bit war,.

Thinking I am going to just wait for my parts, no use blowing the motor.

I think you have problems other than a missing vacuum advance if the car won't start when warm.

I had vac advance problems when I rebuilt my Small Block Chevy (new Eddy aluminum heads, eddy cam, headers, etc) and no matter what I did the motor would either stumble off the line, or fall flat on its face at speed.

The only way I really got any drive-ability out of it was to replace the canister (I bought an adjustable one from Accel... sp?) She pulled like a champ after that.

Sorry man, I feel your pain.

With detonation on acceleration, I'd wait for the right part too.

Curmudgeon wrote: With detonation on acceleration, I'd wait for the right part too.

Well the insurance girl was supposed to come over and see needed to see the car run and drive. But she was super cool and just let me fire it up and roll it into the garage and she cleared me.

So I have insurance cards now, also got my plates in the mail and my new registration stickers.

Chas_H wrote: I think you have problems other than a missing vacuum advance if the car won't start when warm.

perhaps some additional detail would be helpful...

Got the advance this morning, went in, re-timed motor. Ran like crap still. Timing is reading right though on all rpm range.

Pulled carb again. took it to work and threw it in the big old sonicator, water was brown in 5 minutes, changed the water 2x clean. Cleaned out a few little extra bits of dirt. Polished all the jet's and needles with diamond paste. Reassemble, new fuel filter. 10 gallons of fresh gas.

Now it runs like a bat out of hell.

Got it up to about 85 on the freeway, jumps off the line like it should. Lots of fun.

In reply to wearymicrobe:

America. berkeley yeah!

AngryCorvair wrote: In reply to wearymicrobe: America. berkeley yeah!

Its the sound of money exploding when I put my foot down.

I need to figure out the MPG then I will call the motor gone through. Should get ~16 on the freeway driven lightly. Little bit of sticking brakes on takeoff that I need to sort and a bit of brake noise at the rear.

Compressors are working nicely now as well.

Also got another offer on the car today tucked into the windshield when I went out for bread for my wifes diner party tonight.

berkeley yeah!

Haven't heard that since I lived in da UP eh (!)

Rog