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Tue May 30, 2006 11:22 pm

i have a 72 regular beetle, stock engine with 34pict carb. i replaced the original DVDA dist with the 009 dist, and it doesn't run smooth at all (flat spot).

Now, i can't find any new DVDA, i can only find new SVDA. would the SVDA unit work well with my engine set up now? any difference compare to using a DVDA dist. i see used DVDAs for sale, but i don't want to risk of getting a non-working unit.

:roll:

Tue May 30, 2006 11:24 pm

I think you'd be much happier with a brand new 034 dizzy. Although my opinion is probably void because I've never had a DVDA dizzy, I still would rather have a brand new 034

Wed May 31, 2006 12:42 am

Well, if that carburator originally was mated with a DVDA, it will likely run best with one. An SVDA might work OK, you never know, but I've seen it where you switch from DVDA to SVDA or 009 and the resultant change in where you need the carburator set to run well at the 7.5BTDC instead of the DVDA's 5ATDC requires that you set the caruburator way out of where the factory had it set up to run. And that can mean it will never run "right". FYI, here is a chart I compiled of some of the various factory combinations of distributors and carburators. (the carb has a number stamped on its left side at the base flange that you use to tell what series it is)

-Andy

Wed May 31, 2006 3:08 am

Personally if I had a stock engine with a 34PICT-3 carb, i'd use a 034 SVDA.

In fact that the way my 74 originally came and it served me well until I started to modify the engine.

Wed May 31, 2006 3:40 am

I would rather have a new SVDA than a 30 year old DVDA. Just block off that retard vacuum line at the carb.

There should be no change in the car settings.

Wed May 31, 2006 3:57 am

Randy in Maine wrote: I would rather have a new SVDA than a 30 year old DVDA. Just block off that retard vacuum line at the carb.

There should be no change in the car settings.

Randy,

Are you sure that taking a DVDA and not using the retard is the same at a SVDA?

First off the term SVDA and DVDA are generic and just indicate if the type of advance. After all a VJU4BR8 36hp distirubtor is a SVDA. It does have both mechanical and vacuum advance. And 2 DVDA of different models will have slightly different curves. And not using the reatard does not mean it will work like a SVDA... which SVDA?

The reason VW had so many distributors is because the engine combo and carb changed from year to year requiring a distributor with a slightly different curve. Also the goals back in the 70s were related to low emissions.

The Bosch 009 was a "one size fits all" option that everyone adopted since it did away with the vacuum and ran only on engine speed. We all know now that it was not the best distributor in many applications. The original 034 and the new Mexican one are being touted at a "one size fits all" vacuum/mechanical, but they are not. Ask John C. @ AC.net. When you buy one his SVDAs you need to specify which carb you have. He tweaks the distributor to match the vacuum signal for optimum performance.

And in some application a purely mechanical distirbutor will still work great.

I just don't see how taking a a unknown DVDA and nut using the retard will give optimal performance.

Will the engine run... sure it will, but will it run better with the "correct" distributor for that engine combo and appication.

Wed May 31, 2006 4:43 am

:-k

I intended to say "there should be no change in the carb settings" with respect to mixture.

Well I would think that if you have a DVDA (with a working vacuum retard) and intend to use it as such, you just have to time it to the correct idle and the timing set to the 5 or 10º ATDC like it is supposed to.

My experience in DVDAs is really limited to the 70's dual ports and the buses that came with them.

FWIW, I guess some of the auto sticks came with a SVDA from the factory and not sure what kind of carb they came with so I don't really know about the vacuum signal that they would use. Never had one or worked on one.

But that retarded idle timing and the appropriate retard vacuum source goes away as soon as you come off idle and then the distributor works as about any other SVDA would.

If you are going that route (from DVDA to a "modified" DVDA), I say to put a golf T in the retard vacuum line from the carb(s) and leave the retard side of the can exposed to the air. Timing and idle speed would have to be reset a bit to about 850 RPMs and about timing to about 7.5º BTDC or whatever the manufacturer says to. Give it a run and see how it works out. Handy when the retard side of the can is leaking vacuum and it won't hold the timing at idle.

I think the key to about any dual action distributor is to get all of the centrifical advance in (to the specs of 28-32º at about 3500) so that you do not end up with too much advance when you are driving down the road. The vacuum advance on top of that is really sensing the load on the engine and I don't worry about that too much. The distributor has the pretty much covered.

New is pretty good to have sometimes. Those replacement DVDA vacuum cans can be real money like $150.

I don't have an aircooled.net SVDA (saving my dough for a Unilite with the new engine) and right now I am using a 021-905-205P for my bus as opposed to the 039-905-205C DVDA it came with. When I was running the factory DVDA, I did use it as a SVDA and it really ran the same. For the record, I did change out the throttle body, engine wiring harness, ECU, AFM, and other stuff so it is all a match and looks just like a factory set up. The O2 sensor is just there and unhhooked up. Runs about the same as far as I can tell.

That is just my 2 cents. What do you guys think?

Wed May 31, 2006 6:17 am

Sorry to barge in on this discussion, but I just bought an old DVDA and rebuilt it. But the vac can is fubar.

Is there a single vac can I can replace it with? I don't have the exact model of the distributer handy, but it was originally for a 71 or so autostick.

Wed May 31, 2006 6:29 am

If you mix and match parts you'll have no idea what the advance will be.

It will work, but it's a total crap shoot.

Wed May 31, 2006 6:31 am

Gotcha,

thanks Glenn.

Wed May 31, 2006 6:44 am

I don't think that is an easy vacuum can to find. You might get lucky someplace though. Karl over on the bus forum knows a lot about them but apparently there is a number on the black plastic lever of the vacuum can that you need to know. Like 4 digits I think.

Will it hold a vacuum on the advance side?

from www.oldvolkshome.com

Beetle 1971 * 1600 Auto-Stick Trans

Important Note! The listing for this distributor appears ONLY in the Bosch References and does not appear in any Volkswagen Tune-Up References, nor in their Parts Microfilms. It may have been a "Service Replacement".

Distributor: Bosch 0231 167 012
Can Use: VW 113-905-205AH, 0231 167 053 or 043-905-205D, 0231 176 033
Points: 01 011
Condensor: 02 054
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Parts Kit (Shims, Washers & Hardware): 059-998-211, Bosch 1237 010 007
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 083
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 5deg ATDC @ 800-950rpm w/strobe, vacuum hose(s) connected.
Advance/Retard Range: Unknown - May be the same as 113-905-205AH below

--------------------------------------------------------------------------------

Beetle 1971-1973 * 1600 Auto-Stick Trans

Distributor: VW 113-905-205AH, Bosch 0231 167 053 > 043-905-205D, 0231 176 033
Can Use: VW 043-905-205D, Bosch 0231 176 033, 211-905-205Q, 0231 167 055, 211-905-205S, 0231 173 001
Points: 01 011
Points Replacement Plate Assy: VW 311-905-227C, Bosch 1237 110 161
Condensor: 02 054
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Parts Kit (Shims, Washers & Hardware): 059-998-211, Bosch 1237 010 007
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 092
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 5deg ATDC @ 800-950rpm w/strobe, vacuum hose(s) connected.
Advance/Retard Range: Vacuum: 2-5deg Adv, 11-13deg Ret; Centrifugal: 12-16deg @ 2200rpm, 22-25deg @ 3800rpm

Wed May 31, 2006 11:28 am

That vacuum can is available at the BusDepot, where they have a couple of dozen advances listed for sale (do a search for keyword: advance to see the others there)

http://www.busdepot.com/details.jsp?partnumber=07083

but at almost 80 bucks you might be better off buying a new SVDA and hoping it likes your carburator.

In many cases, in my experience, a lot of old DVDA's have pretty worn out advance plates. I think it comes from having it pushed and pulled by the dual advances so much over a long lifespan. Especially if it was never lubed. So with this wear, the breaker plate can wobble a bit, and wobbling affects the dwell, not really a good thing. They can also bind, which is worse. So as mentioned above, getting a good new 034 SVDA is likely going to be a better distributor. Whether it likes your carb or not, the only sure way to know is to try it.

Now as for my comment above about changes in carb settings. (talking Type 1 34PICT-3 here) I've experienced it too many times to say it won't happen. Three will have to be some changes. Soemtimes you can get them to run good, sometimes not. But when the carb was designed to idle at 5°ATDC then you shoot up to 7°BTDC, the RPMs will be a lot higher. To compensate you're going to have to crank down on the air bypass screw on the side of the carb. I've seen it where this is done and you have to turn that bypass screw all the way down to the bottom to get the idle RPM at a decent level. I've seen it where you go the other way, and have to have the air bypass screw about all the way out just to get up to 900RPM. Maybe there were other problems with the carbs in those instances, such as worn out throttle shaft bushings or dirt inside the carbs that added to the problems. But regardless of that, there WILL have to be adjustments made to compensate for a 12 degree shift in timing at idle on most DVDA's.

If you were just eliminating the retard side of an existing DVDA to turn it into an SVDA, note that two of the DVDA's VW used on the for the type I, the 1139095205AD and the late model 043905205J only have about 7 degrees of retard, and to compensate on those you'd want to set your idle timing to about 2° BTDC. The others had about 12 degrees of retard, so on those you'd want to go to 7.5°BTDC.

-Andy

Wed May 31, 2006 5:23 pm

I totally agree with Andy, his chart and suggestions have helped me out tremendoulsy, I can now run a stock carb with my new SVDA. The other carb I tried using was from an autostick with a DVDA and I couldn't get it to idle below 1100. I looked at it versus another carb I have and noticed that the throttle plate had a larger hole in it, the other carb was originally from a car with an SVDA. It make so much sense, bigger hole = more air = more gas = higher idle, there was no way it could be set correctly.

Andy if I didn't say it before, thanks a million!

Greg

Wed May 31, 2006 5:51 pm

Fibersport wrote:
Andy if I didn't say it before, thanks a million!

Greg

thanks Greg, you're welcome. I wasn't aware of the larger hole in the throttle plate before, ya learn something new every day! I knew from experience there were differences between the various carbs, which is why I compiled that chart in the first place, but the size of that hole was a detail I hadn't noticed before. Makes me wonder what, if any, other "plumbing" differences there are internal to those carbs.

-Andy

Wed May 31, 2006 7:37 pm

thx for all the opinions and input :D

right now, i am using the 009, and i wont be able to set to fatory timing @ 5ATDC.

the old DVDA that used to be on my car was not working properly because the due vacuum was shot.

i think i will either get a vacuum and replace it to my old DVDA and see if that'll work, or just get a new 034 dist.

if i replace it with the 034 dist, i dun think i can set back to factory timing @ 5degree ATDC. if 034 is used, what is the optimum degree? 7.5BTDC??

Thu Jun 01, 2006 1:16 am

Yes, the 034 is designed to run at 7.5°BTDC. But, as noted above, you may or may not have some trouble getting that DVDA carb to idle well at that timing.

-Andy

Thu Jun 01, 2006 4:19 am

Fine post Andy!

I never realized how inter-related all of that was. Thank you!

Thu Jun 01, 2006 7:32 am

glutamodo wrote: Yes, the 034 is designed to run at 7.5°BTDC. But, as noted above, you may or may not have some trouble getting that DVDA carb to idle well at that timing.

-Andy

got it! :wink: thanks for all the info andy

Mon Oct 03, 2011 12:27 am

I'm reviving this post, it is excellent info! Here is a question, what if you have a Brosol or Pierburg 34 PICT? Or even, gulp, a Chinese copy? I guess the 034 SVDA is the way to go?

Sun Jun 05, 2016 9:09 am

FYI - I just cleaned and repaired my DVDA, I didn't find any wear in the breaker plate at all, one problem I did find though was the little ball bearing that sits under a cup holding down the breaker plate had moved to the wrong position and was letting the vacuum advance go too far, it may also have mucked up the grounding (not sure), and I had a hesitation from this in driving (79 FI beetle), I think. It's pretty easy to take it all apart and clean. I would suggest really small amounts of oiling, the plate moves easy without it.

I compared it with my spare modern SVDA and they are very similar design except that the vacuum canister is much bigger on the DVDA and of course it has the two ports. The older DVDA is, ha ha, in better condition and has no blemishes. It would be possible to swap the vacuum can, but I haven't done that. I can say that the original runs better with the FI than the replacement SVDA, just about, perhaps because I know the settings to start with.