Vacuum Leak Questions, 1973 Super Beetle

[Beetlebaum]

Hello all! Sorry I've been off TheSamba for so long...but here's my problem.
1973 Super, 1600 engine, freshly rebuilt.
I am still having the same old issues with it, even after rebuilding both the engine and the carb. I took a vacuum tester to the distributor, and it doesn't hold vacuum. As soon as the tool stops increasing the vacuum, the pressure starts falling to normal air pressure. Am I correct in my belief that the diaphragm is not supposed to leak at all? (Interestingly, the distributor is a dual-vacuum one, and the side the retards the timing does hold vacuum. The vacuum line also appears good.

Secondly, there's a vacuum port below the carb, on the intake manifold. I have it going up to the air filter, but when I tested the side of the hose that goes to the intake manifold, there's absolutely no vacuum at all. Does that make sense, and what should I do about that?

Finally, it seems like I may have discovered the root(s) of all of Beetlebaum's issues!!!!
Thanks for your help!
_________________
1973 Super Beetle
2003 New Beetle
Post your Super here: http://www.thesamba.com/vw/forum/viewtopic.php?t=331999
Beetle Bums VW Club Member

[Tim Donahoe]

That vacuum line under the carb is for operating your pre-heat thermostat in your air cleaner. If, when the engine is running, you have no vacuum there, something is plugged. That particular orifice has a lot of vacuum, ordinarily--to open the thermostatically-controled warm air door in the air cleaner when the temps are below 81 degrees F (I think that's around the right number).

Perhaps a PO plugged the line because his thermostat did not work and it was actually causing a vacuum leak, as a result--and he knew it.

This vacuum line/thermostat arrangement is often overlooked as the culprit for a vacuum leak. An old thermostat can leak and cause a vacuum leak.

I'm assuming you have the paper-element air filter. If so, are you checking the vacuum line that feeds directly off the manifold port? and no vacuum? Or are you testing the right-side vacuum line? If testing the right side and there's no vacuum (when it's a cold morning--like 65 degrees), your thermostat is wasted; and with no vacuum, your pre-heat door will not open, and you'll have to get new one from Germansupply in Canada (that's right, Canada).

But if your left-side hose is plugged, then replace it. Or, if you don't care about pre-heating for winter (which you should), just plug the manifold port with a piece of hose and a screw--or nice little female sheath that fits nice and tight.

Tim

[Beetlebaum]

[cletus_zuber]

and it sounds like the vacuum canister on your dual vac (DVDA) is blown, not surprising after 40 years. you can plug the vacuum port on the side of the carb and run it as a strictly mechanical advance for now, timed at 30° btdc at 3000+rpm. also plug the retard vacuum port. you can try to find another DVDA, or a new ($) or used vacuum can, or replace it with one of the many svda or 009 style distributors available.
_________________
1972 1302
HPMX 40's & 019

[Beetlebaum]

Hello all,
Allow me to resurrect an ancient topic regarding my car. So, all through this past summer, I couldn't get the car to run, and so I am wondering whether I didn't tighten the intake manifolds to the cylinder heads with enough torque (which would almost certainly cause debilitating vacuum leaks, correct?). Is there a way to tighten these without having the engine out of the car? Can I get there without removing the tin?

Thanks!
_________________
1973 Super Beetle
2003 New Beetle
Post your Super here: http://www.thesamba.com/vw/forum/viewtopic.php?t=331999
Beetle Bums VW Club Member

[Tim Donahoe]

I assume you have a 1600Dual Port engine.

Did you use the metal-crush gaskets?

They torque to 14 ft. lbs.

I suppose you could get a socket with a universal on the front ones (front of the engine--toward the cabin). But the back ones need a 12 point wrench. Give them a try--but don't overtorque. 14 ft. lbs. is not a lot.

Also check your manifold boots--spray some WD40 or carb cleaner to see. Check the manifold boot clamps for a snug (not to tight, though) fit.

Tim

Tim