Please help me put the pieces of this puzzle together...

[sb001]

... and figure out what in the world is going on with my car.

A bit of back story here in case it matters: A few weeks ago I noticed my timing was bouncing back and forth. I pulled the distributor and discovered I was either missing some shims or they disintegrated, either way there was a lot of vertical play in my distributor shaft. I reshimmed the distributor and reinstalled it, but got sidetracked and forgot to re-time before driving it again. In the couple weeks I drove it like that it drove great- with the exception of a bit higher idle than normal. I finally realized I had forgotten to reset the timing so I did. It drove fine for another week or so.

Then, over the past few days, it has suddenly developed the following symptoms:

With engine completely warmed up, bog down and eventual stalling when idling in gear (generator/ oil pressure lights come on), but slightly over-revving if I kick it back into neutral. Difficult to get back into gear when it is over-revving in neutral like that.

Can drive until engine warmed up (stepped cam on lowest setting) turn car off, turn back on after only a couple minutes and stepped cam has returned to higher setting.

Extremely erratic idle. Surging/ chugging when trying to set timing and popping/ misfiring out exhaust-- like a serious vacuum leak- RPMs can jump up suddenly to as much as 1400 RPM and then drop to 700 with the slightest rotation of distributor body.

Maybe most important clue: Timing increases/ decreases with adjustment of bypass screw on carb when trying to set idle. Also my DVDA vacuum canister should provide around 7.5 degrees of timing retard at idle- timing on my car is set to 0 TDC with both hoses connected, so if I remove and plug the retard hose the timing should jump up to my 7.5 BTDC mark. However when I do this test, the timing jumps all the way up to around 15 BTDC!!

Obviously the very first thing that pops into mind is a seriously bad vacuum leak somewhere. Because of the significant bog down when shifting into gear, my thought was a leak in the autostick vacuum system somewhere- but I have checked all hoses, the clutch servo, the vacuum storage tank etc and sprayed all around those items with carb cleaner with no change. Plus all those hoses are fairly new- installed within the last couple years.

Many vacuum leaks seem to be carb related, so I sprayed all the usual suspect areas- carb base, throttle shaft, etc, with no significant effect. I also find it hard to suspect the carb since it was rebuilt by volkzbitz just a couple years ago as well.

One thing I mentioned in another thread that I will mention here as well- I have never been able to suck on my vacuum can hoses and have the points plate move. This may indicate a problem with the canister, but the car has run just fine up until this point. I went ahead and ordered a NOS correct replacement canister off our favorite auction site since it was only $50 (be nice to have a spare regardless.) The autostick carbs supply much more vacuum to their corresponding DVDA distributors than do the regular carbs to the SVA distributors, so that might explain why I cannot suck on the hoses and have the points plate move.

One more thing- I pulled the distributor a couple days ago and installed another condenser to see if that solved anything (it did not.) When I had the distributor out, I noticed a small pool of motor oil down the distributor shaft hole. I attributed this to accidentally dripping too much oil on the shaft wick when reinstalling the distributor the first time- could that in any way be contributing to the problem?

Sorry for the long post, but I am pulling my hair out needing to get this solved. My other car is dead (long story but it probably is not coming back to life) so this is my only way to get around for awhile. Any thoughts/ opinions are welcome. Thanks
_________________
I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[Ricksurfin]

Heat risers clear?

[Cusser]

[Pruneman99]

What distributor? Most get timed with the hoses DISCONNECTED and plugged. If you're timing with it with the hoses connected, you're fighting the vacuum cans. Hence the timing is moving when adjusting the carb.

Edit:

I remembered you were running the autostick distributor now...

That was the oddball that does get timed with the hoses connected I think. If I remember it was timed at TDC or 5* ATDC.

See if you can find the service sheet that covers it.

[VW_Jimbo]

It has all the symptoms of a vacuum leak. I think you are confusing ported and manifold vacuum in your investigative work. Be careful.

You should remove the vacuum hoses to all devices by plugging their ports at the carb. How does the car respond?

Tighten the carb to the manifold.

Tighten the end casting nuts at the heads.

Adjust your valves. I know, I know, you just did it. Just go through and check them. Sometimes those senior moments interfere with the way we work. Worth it to double check.

Start their and report back if there was any change.
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[baldessariclan]

[sb001]

[sb001]

[sb001]

[sb001]

[sb001]

[Pruneman99]

The timing will be affected by high idle. At high idle the mechanical advance starts advancing. What is the idle setting for your autostick, and what is you engine idling at?

[sb001]

[Frank Bassman]

Does the distributor rotor spring back to its proper position when you take the cap off and twist it?

If I remember correctly in these aluminum distributors the two springs are slightly different... one of them is physically secure when the distributor is not advanced, and one has a SLIGHT slack. If the one that keeps the system retracted and is responsible for low RPM driving is broken, that means the one that has slack is now the minimum stop.

If that is the case, then you will have an annoying intermittent idle up and down situation that will drive you off the wall... The action of the rotor should be smooth and linear, and the rotor should return to a POSITIVE stop, not a "stepped" motion. You'll quickly feel with your hand if there is a problem or not.

Easy enough to test.

Good luck.

-Frank

[Starbucket]

Are you your can hoses are on the right nipples on the carb? Post a pic and someone might spot a problem with your hose plumbing. Maybe your fuel pressure is too high or wrong float level causing excess gas to spill into manifold causing the serge and flooding out at a stop when hot. You could have a helper jump out when it starts to die and see if black smoke is coming out of pipes (flooding).

[VW_Jimbo]

[baldessariclan]

[sb001]

Thanks for all the help guys.
Sorry I haven't been updating, been out there for the last 4-5 hours chasing these issues. Finally got it tracked down...
There were actually two issues. The first I am embarrassed about, because I have actually helped others track down that same issue. When I pulled the distributor to change the condenser few days ago, I did not get it all the way back down in the hole to engage the distributor drive gear. The dog ears on the distributor shaft were partially engaging but not completely, causing some of the issue. Also, my points gap was WAY off, probably as a result of me pulling the shaft to reshim the distributor a few weeks ago and then forgetting to recheck the points gap when I put it back together. CHalk this one up to my complete ignorance.
However, after I located and fixed these issues, there was still a terrible surge, like a vacuum leak. Apparently, when I checked for the leak the other day, the one place I did NOT spray was the right hand side of the throttle shaft-- that's where the leak is. I sprayed the left hand side and there was not really any change but then I sprayed the right side and voila the revs immediately flew up. I took a video I'll post a bit later but that's definitely the issue.
Anyone happen to know what volkzbitz's warranty is on rebuilding carbs? I sent this carb in about 2 1/2 years ago to fix the same issue... here is that thread concerning the previous vacuum leak and our correpsondence:

https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

EDIT: I just saw on volkzbitz's front page that he guarantees his work for 3 years. I have sent an email, hopefully he can help me out again.
_________________
I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[ashman40]

Glad you found the problems, but I wanted to add a few comments based on the statements given above....maybe it will help the next person with these symptoms.

Vacuum retard cans typically retard timing by 8-12deg. This is for the manual transmission models so maybe the autostick ones are different. So the jump from TDC to 15BTDC is not that far off the mark.

Part of the 15deg of added timing advance when you disconnect the vacuum retard hose could be coming from a faster idle rpms. You mentioned idel rpms were jumping as high as 1400rpm which means mechanical advance could be adding timing. When the vacuum retard is connected it removes timing advance which will actually drop the idle rpms. When you get the rpms back by disconnecting the retard hose you need to be careful to discount any additional timing caused by mechanical advance kicking in as the rpms rise. You can use the bypass screw to reduce the rpms back into the normal range of 800-1000rpm then take your readings (I know your idle rpms were jumping around so this could be hard). At rpms below ~1000rpm the mechanical advance should not yet be adding timing. If dropping the rpms into the normal idle range brings your timing back into the 8-12BTDC range then you know the extra few deg are coming from mechanical advance.

On the point of adjusting the bypass screw causes the timing to change, if this adjustment has your rpms up above 1000rpm then you are correct. But it is NOT the bypass screw affecting the timing directly. The bypass screw is increasing the idle rpms to the point where mechanical advance is starting to kick in. It is actually the mechanical advance that is causing the timing to change. I got the impression that you were thinking that somehow the bypass screw was changing the vacuum levels so directly affecting the vacuum advance/retard. I don't think this is the case.
Related to this point, you want to make sure at warmed up idle the throttle plate is fully closed and blocking off the vacuum advance (ported) vacuum holes at the bottom of the carb throat. If the throttle plate is opened enough with the fast idle screw to expose these small ported vacuum holes to intake vacuum at warmed up idle it WILL affect the vacuum advance. This is why the throttle arms screw is turned in only 1/4 to 1/2 turn from contacting the lowest level of the fast idle cam. This keeps the throttle plates off the walls but keeps them from exposing the ported vacuum holes to vacuum.

On the description of vacuum retard adding timing advance, the better way to think of this is when you disconnect the vacuum retard it gives back timing advance that it had taken away. There is an important distinction...
Vacuum advance and mechanical advance are "additive". They add to the initial timing (not necessarily the same as idle timing). Vacuum retard takes away timing degrees from the initial timing (notice I didn't say idle timing) resulting in an idle timing lower than the initial/stick timing. Vacuum retard does not "add" timing advance it removes it.

Let me walk thru how this all comes together, for example:
static timing = 7BTDC (set with the engine not running)
initial timing = 7BTDC (engine idling @800-1000rpm; vacuum hoses disconnected & plugged; no advances or retards applied to static timing)
vacuum retard = -12deg (vacuum retard hose connected; engine idle rpms readjusted to prevent mechanical advance)
idle timing = 5ATDC (both hoses connected; vacuum retard is removing 12deg of timing)
vacuum advance = +8~12deg
off idle advance @1200rpm = 15BTDC (vacuum retard has shutdown giving back the -12deg it had taken; vacuum advance is fully advancing now that ported vacuum port is exposed to strong intake vacuum (+8deg).
mechanical advance = +18~22deg variable; increasing as rpms increase. Add this to the initial timing gets you into the 28-32BTDC range for total advance at max rpms. This is how 009 distributor timing is set to make sure the total advance never exceeds a safe max of 32BTDC at ANY rpm.
vacuum advance (cruise) = +8~12deg at high intake vacuum (high engine rpms + low engine load; aka. cruise). This vacuum variable is based on load at rpms above idle. This is added to the mechanical advance which is rpm based. It can be different at the same rpms depending on the engine load (and other variables) which is why you do NOT set total advance with the vacuum advance connected.

_________________
AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[Ricksurfin]

Thanks ashman, great post breaking it down.