Vacuum advace from where?, I swear I serched but did't quite get what i was looking for Options

[914chic]

Alright i recently converted my 74 fuel injected to carbs and was wondering what you guys did for the vacuum advance on the distributor , the only way I can see doing this is tapping into the intake or what . Calling on you joe sharp if you got ant ideas?, or anyone , thanks alot.

[SLITS]

Run a 1.8 dizzy w/o vacuum advance or spend mucho money on a Mallory.

The vacuum advance is really only functional at part throttle cruise (for increased gas mileage) and closed throttle deacceleration (emission control).

Your carbs may have a boss in the base to tap into with a 1/8" copper pipe (yeh, you have to drill the hole).

[Demick]

Just plug it. Your '74 didn't have vacuum advance from the factory anyway.....

[McMark]

And do a little google-ing on how vaccum advance works. (That comes across insulting, but really it's an interesting read) Tapping into the manifold would NOT give you the desired results. If you need to run vacuum advance, then there is a port on some of the throttle bodies (assuming 2.0 here, car stats in your signature really help). Some of the throttle bodies don't have them, so you'll have to look around if you don't already have the right one.

[r_towle]

Dont plug it, leave the port on the dizzy open or you will create a vacuum inside the distributor advance can that will not allow it to advance the plates, unless the can is already leaking.

Just leave it unplugged and open to the air.

The vacuum advance moves the advance plates only when at low idle and you dont have enough centrifical force to swing the advance plates into full advance. Without it, you still have full advance, just not as fast as with vacuum.

On webers there is a little bung (you need to drill as Slits said) down near the bottom on the outside of the carb. There are two bungs, one per venturi, but you would only need one. It is located at the bottom, next to the air mixture screw...you will see it.
If you buy a simple 1/8 inch NPT brass piece from the hardware store, that is the item that you drill, tap and put in there. The outer portion is 1/8 inch with a barbed collar to hold the hose.

I would say try it without first to see what it feels like.
The Decel, or retard port (if you have one) is to reduce emmissions by closing down the advance plates faster...it also gives better idle...
It brings the car back to idle faster, so you reduce emmissions and save a little gas.

Rich

[Joe Owensby]

There is some good information on distributors and vacuum advance at aircooled.net.

[pete914]

I'm running dual webers with a vacuum advance dizzy (stock) and I notice a significant difference in acceleration without the vacuum line hooked up (it lags). So, take it from me, it's worth it to hook it up.
also, it doesn't hook up to the manifold. there is a proper place on the carb where it meets up with the throttle plate.

Out of curiosity, what happened to your FI?

[r_towle]

you need to grease you dizzy plates. There should be no lag.

Rich

[Gint]

I'm running dual webers with a vacuum advance dizzy (stock) and I notice a significant difference in acceleration without the vacuum line hooked up (it lags). So, take it from me, it's worth it to hook it up.
also, it doesn't hook up to the manifold. there is a proper place on the carb where it meets up with the throttle plate.

Out of curiosity, what happened to your FI?

Except Pete it sounds like is that you have one of the rare carb'd 914's that have a carb tapped for vacuum. 95% of the Weber carb'd 914's out there do not have a port(s) tapped. So in your case it would make a differnece. Without a vacuum source though, as is the case here, it won't matter at all from a performance standpoint if the vacuum port on the canister on the dizzy is plugged or not.

With the exception of Rich's comment of course. I'd never heard that one before.

[r_towle]

With the exception of Rich's comment of course. I'd never heard that one before.

If you look at the vacuum can or vacuum POT setup it is hooked to the advance plates. If the POT is all working and you plug the end, you will add resistance to the advance plates.

When the plates advance they will push on the arm and this will push on the diaphram in the POT...this is a simple vacuum or worse a bubble on the outer section of the POT and just enough resistance that it will make it hard to get full advance...

Thus either leave it off, or remove the POT all together and that will also remove just one more moving part that the advance plates need to push against...

Less friction, faster advance.
Grease the plates...it 40 year old grease that behaves like glue now...

Rich

[jesiv]

With the exception of Rich's comment of course. I'd never heard that one before.

If you look at the vacuum can or vacuum POT setup it is hooked to the advance plates. If the POT is all working and you plug the end, you will add resistance to the advance plates.

When the plates advance they will push on the arm and this will push on the diaphram in the POT...this is a simple vacuum or worse a bubble on the outer section of the POT and just enough resistance that it will make it hard to get full advance...

Thus either leave it off, or remove the POT all together and that will also remove just one more moving part that the advance plates need to push against...

Less friction, faster advance.
Grease the plates...it 40 year old grease that behaves like glue now...

Rich

Rich,

What type of grease do you use?


Regards,

James

[Gint]

Rich,
Yeah, that makes sense. Operates on a vacuum so if sealed and acted upon by the mechanical advance it will provide resistance that otherwise wouldn't be present if left un-plugged. Never gave it a thought.

One of the first things I do when I buy a *new* 914 is to find and verify timing and marks and clean and re-lube the dizzy. Along with replace vacuum lines, and... well, you know.

James,
Bosch distributor grease. Pelican carries it. Or any shop that works on classic cars will have some. A tube of the stuff will last a lifetime. Looks like this: http://www.pelicanparts.com/catalog/shopca..._pg3.htm#item19

[914chic]

Thanks alot to everybody for the info , and in regards to the fuel injection , I had wire short out and melt to like 6 other wires in the harness , beyond repairable and besides it seemed like I was having to dump more and more money on stuff that I did't want too but thats part of owning 914 right?

[jesiv]

Thanks alot to everybody for the info , and in regards to the fuel injection , I had wire short out and melt to like 6 other wires in the harness , beyond repairable and besides it seemed like I was having to dump more and more money on stuff that I did't want too but thats part of owning 914 right?

If it is 2.0 D-Jet do you want to sell components.

James

[E-Man]

Go to weberpartsdirect.com and navigate to the Exploded Views/Parts List for your carburator. The screw is called a Vaccuum Take Off Cover.

Do what Rich said to do. -Mike

[SLITS]

Thus either leave it off, or remove the POT all together and that will also remove just one more moving part that the advance plates need to push against...

Rich

Centrigfugal advance (mechanical) moves the point cam in relation to the drive NOT the point plate.

Removing the POT will allow for movement of the point attachment plate and will really fuch up your ability to time the engine (you won't be able to). If you do remove it, you will have to fix the plate by running a screw thru it or soldering it in place.