Timing a single vacuum advance distributor for a beginner

[bluenose]

That's wrong carb for vac only dizzy, u need svda one


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Every day's a school day!

How do you know this though? I've tried searching for some info on this dizzy, and the only reference I can find is on a table listed on thesamba - which states it is for a 1969 1600 bus. As mine is a 1970, I figured it could be original to it. The engine is a 1600 TP, but again, I'm not sure what it came with originally.

Just trying to unpick the PO's changes and figure out what has been done!

I have a vac only dizzy so I read up on it when I was looking for a new carb, there was a great thread on the samba where someone had gone to great length looking at the differences but sadly I can't find the link now.

Basically the vac ports in the carb are different sizes and in different positions internally depending on what dizzy it's matched to

In a nut shell;
30pict1/2/3 carbs are for single port with vac only.

31pict4 is for twin port with SVDA

 

[bluenose]

according to wiki dual port started in 71. So I guess could be the original dizzy but not engine/carb

 

[Bluesnailman]

That's wrong carb for vac only dizzy, u need svda one


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From the earlier description it sounds like an SVDA to me as when revved with vacuum plugged it advances to 24 degrees. Suggests there is a mechanical advance as well

Sorry - descriptions earlier in the thread probably weren't clear enough. It is vac advance only, the canister had to be plumbed to the carb to get it to advance when revved.

Are you sure its vac only? Do you have two vac connections. One advances when the throttle is open, the other ******* in when the throttle is closed. Is the retard one missing?

 

[Moseley]

Definitely a single vac only - at least that is what the internals are that are in it currently. It is fitted with electronic ignition, so I couldn't tell what 'unused' connection inside it were mountings for the points, or whether they served another purpose once upon a time.

Anyway, to update, I have ordered a powerspark SVDA that has now arrived. Whilst I was waiting for this to turn up, I put the old dizzy back in, just to see what my strip down and clean had done. And success - timed dynamically to 30 degrees advance with the vac can connected, the engine returns to zero degrees at idle. Nothing else changed in this time since having the problems at the start of the thread.

I will be trying the SVDA next, but at least it proves the other dizzy just needed a clean to function properly. Will make a good backup, if nothing else.

Happy again now.

 

[Bluesnailman]

glad it working again.... thats the main thing