SVDA dizzy question

[chenzo]

when setting the timing on a 1600tp/pict 34/SVDA dizzy (with electronic ign) do you check max advance with the vac hose on or off?

at the moment I have set it with the vac line off and blanked so that max advance is 28deg btdc

this give an idle setting of 0deg (tdc) and it seems to run pretty well but think it is a bit lean.

one of the manuals I have says that for a svda with electronic ignition it needs to be set to 5deg ATDC(!) but that just seems wrong to me.

 

[creationblue]

From VW Resource:

Setting the 009 Centrifugal Advance, Single-Vacuum Dual Advance (SVDA) and Vacuum-Only Distributors with a Strobe -

Note: The approximate idle timing setting for the centrifugal advance distributor (009), the single-vacuum distributor, and the vacuum-advance only distributor, is 7.5o Before Top Dead Center (BTDC). This means that as you view the 7.5o mark at the crankcase split (with the strobe), the TDC mark on the pulley will be about 11.5mm to the LEFT of the crankcase split when the distributor is properly timed. Again, this is the APPROXIMATE timing setting at idle.

Important Note regarding vacuum lines:When timing the vacuum-only distributor, the vacuum line(s) must be attached. The vacuum line on the single-vacuum dual advance (SVDA) distributors must be removed from the vacuum canister on the distributor and plugged to prevent air from being sucked into the carburetor during timing. For BOTH the centrifugal-advance (009) and SVDA distributors -- if there is a vacuum hose running from a port in the intake manifold under the carburetor up to the air cleaner, this hose must be removed and plugged as well, for the same reason. Be sure to plug it such that air will not be sucked into the intake manifold.

Summary regarding vacuum hoses during timing: Just make sure the vacuum ports on both the carburetor and the intake manifold are PLUGGED so air won't be sucked in during timing.

For these distributors, the advance timing is more important than the idle timing. Ideally it should be 28-30o advanced at 3500 rpm, then should return to something close to 7.5o BTDC at idle (900 rpm). The centrifugal-advance portions of these distributors vary -- if the maximum advance is set to the correct 28-30o BTDC at 3500 rpm, an idle timing in the range of 5-8o BTDC should result.

Just

 

[chenzo]

thanks Just,

i initially timed it at 7.5 deg btdc with the hose on and checked the max advance which was more like 40deg.

then i thought it would be better to check the max advance with the hose off as throttle position/manifold vacuum would be varying under load. retarded the timing so that max advance with the hose off was 28 deg btdc. engine seemed to be running better like that but it gave an idle setting of 0deg.

as i think it is running a bit lean i'm not too keen on advancing it at all until i can get a decent road test in and pull the plugs.

 

[Trikky2]

Yes you set them with hoses off.

The only dissys you set with hoses on are the ones with a double vac unit (fuel emission). These are easy to tell apart because they are the only ones with two vac pipes going to two different ports on the carb. Most of these in the UK will have been replaced long ago since they caused flat spots but you still see one or two, mostly on US imports.

For reasons I never understood the carbs on 1600 transporters had idle and main jets one size smaller than the 1600 beetles. Back in the day it was common to change these two jets for beetle sizes to improve running and, strangly, the mpg improved too, probably because it didnt need such a boot full of pedal to get moving :lol:

The 5 after tdc setting you mention is the dreaded double vac emissions model set with hoses on btw. I wish the manuals and web sites would make this more clear since its confusing to those who are not ancient and remember all this sh*t :lol:

 

[bluelighttaxidriver]

Interesting about the jet sizes. What sizes are the beetle jets, compared to that used on a bay...?

 

[six]

dont forget to plug your vac line from the carb when you disconnect it too.

Just done this very same job yesterday after the now defunct airspeed set my engine up ready to run.. timing settings were 7.5 deg ATDC! needless to say its running a whole world better now, i warmed it up set it to 30deg at 3500rpm.. it settles nicely also on 7.5 deg at idle

cheers
6

 

[Trikky2]

dont forget to plug your vac line from the carb when you disconnect it too.

Just done this very same job yesterday after the now defunct airspeed set my engine up ready to run.. timing settings were 7.5 deg ATDC! needless to say its running a whole world better now, i warmed it up set it to 30deg at 3500rpm.. it settles nicely also on 7.5 deg at idle

cheers
6

Just goes to show how important it is to check everything before using a new engine :!:

Had you driven it at 7.5 ATDC for any length of time its likely the exhaust valves would have suffered severely.

 

[six]

just done 100 miles on it! was bought turnkey (in hindsight the correct phrase is I bought a turkey).. I didnt have strobe then to check and I had to believe and trust it was done right after all thats what i paid my money for.. glad i caught it now.. hopefully its not done too much damage.

One one hand its say I dont feel I can trust many to do a job I pay for. But the upside is once I've made the purchase of these tools I can use them and will save money not having to pay for it

 

[froggy]

Most SVDA's are set to 7.5 deg BTDC with vac hose disconnected AND BLOCKED.

In all honesty though you need to know the dizzy number (205**) and then have a look at the old volks home web site and set it accordingly.
Electronic ignition does not effect the timing settings it just gives you an electronic set of points / condensor.

 

[robjarman]

this is the timing info from The Old Volks Home excellent website http://www.oldvolkshome.com/ignition.htm#A905205ZB" onclick="window.open(this.href);return false;

(Puebla, Mexico) With Points Distributor

Distributor: VW 043-905-205 ZB, Bosch 0231 170 034 (Mexico)
Can Use: VW 113-905-205AL, Bosch 0231 146 101, VW 043 905 205, 0231 170 034 (German)
Notes: This is the Mexican manufactured version of the original 043 905 205 Distributor, originally used on 1974 Federal Manual Transmission Beetles. This was used on Mexican production Beetles early on before they switched to Electronic Ignition (year periods are unknown, but I believe it was sometime in the 80s). This distributor comes with a Single Vacuum Can is essentially a carbon copy of the original German made model. It uses all of the same components of the original German Distributor except the Condensor as noted below. Timing specs are the same as well and have not changed.
This is THE Distributor to use on your stock engine w/Solex 30PICT-3, H30/31PICT Series or 34PICT Series carbureted 1600 Beetle thru 1974 (75-79 w/Carb) & Type 2 1600 thru 1971. It is NOT recommended for use with the 30PICT-1 or 30PICT-2 because the vacuum signal is incorrect for the vacuum assist to work properly. This Distributor is essentially a "009" with a Vacuum Advance Assist to help prevent hesitation in all of those Stop-n-Go situations in city traffic. The Mechanical Advance takes over out on the highway to provide the most excellent Advance Curve in all sorts of engine loads. If you're running an original Dual-Vacuum Distributor on your Beetle 71-74/Type 2 1971 application(s), you will need to cap off the "Retard" Vacuum Port located on the rear of the Carburetor. Available new from a number of VW Parts Suppliers.
This distributor is similar to but should not to be confused with the "Bruck Germany" Distributor being sold by a number of outfits. In actuality, this is a Chinese knock-off of the Bosch Mexican "034" and the reliability of this distributor has not yet proven itself IMHO. Let the buyer and user beware!
Points: 01 011
Condensor: 02 054 (German model used 02 074)
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: 07 059
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 7.5deg BTDC @ 800-950rpm w/strobe and w/single vacuum hose disconnected and plugged
Advance/Retard Range: Vacuum: 8-12deg Adv; Centrifugal: 8deg @ 1300rpm, 10deg @ 1600rpm, 15deg @ 2500rpm, 20deg @ 3000rpm, 21deg @ 3500 to 4000rpm
Note: The Advance ranges shown are courtesy of Richard Atwell who performed a test of this distributor's capabilities on a Sun Distributor testing machine. You can view the appropriate advance graph images at the following links (click on them): Vacuum Advance, Centrifigual (Mechanical)

Rob

 

[six]

feel like im hijacking this now!

i run pn 043905205N i think thats a mexico bosch one .. by your post looks like ive got my advance too high.. ive set mine at 30 @ 3500 i should wind that down to 21 by that post .. thanks

 

[Trikky2]

Just a couple of points (terrible pun).

Firstly - The old Volkshome is good site for info but it should be remembered this is a US site and hence some of the data regarding dissys and engine numbers is not accurate for European spec vehicles. US spec dubs were considerably different to take account of the more severe federal legislation that started coming in in the early seventies onwards. Many of the carb jets and settings, injection and ignition timings were different to comply with anti smog/ emission control legislation. Vehicle performance and MPG suffered but at the time it was the only way to comply.

(just as an aside - back in the early days there were a few manufacturers of large engined vehicles (I aint mentioning no names) that met the anti smog rules by adding an air pump, driven by the fan belt, that pumped more air into the exhaust thus reducing the readings taken by the probe) :lol:

Secondly - although the information on any given distributor may be accurate, its actual setting will be different if its not being used on the engine/carb/injection system it was designed for.

So what to do?

Simple - look up the dissy specs as should be fitted to your european spec engine eg the amount of cetrifugal and vac advance at x rpm. Next look up the specs of the of the dissy you have or are intending to fit. With any luck they will be similar enough to allow you to set your timing as per standard for your engine.

If on the other hand the advance curves are markedly different from what is specified for your type of engine then you should not use it. There are companys that will set up your dissy for you, its as simple as changing weight, springs and vac can if necessary.

If your running a dissy and your not sure what its doing but need to run it in the meanwhile then just set it so it doesent give more advance than 28 at 3500 hoses off and then check by attaching the hose that it doesent go up by more than about 4 or 5 deg max. That way you wont do any damage to the engine and will be getting the best out of the dissy.

ps. If you have a twin vac can unit on a T1 engine then it pays to change it or just the vac can for a single one. (The dissy will be fine). Then set your timing to the usual 7.5 btdc rather than the 5 ATDC (hoses on) specified for the twin vac. It will run better and give you better mpg to boot.

Some dubs were fitted with a vac only dissy (like the reverse of an 009) - although they and 009s work they are not as good as an svda - that is assuming the svda is in good condition of course :lol: