Hi, I have an AD 1600 twin port engine thats fitted with a dual vacuum distributor. my question is, can i just remove one of the hoses (the one at the back?) to turn it into a single vacuum, will this work correctly and what should i set the timing to?
dual vacuum distributor
- Thread starter vwcamper
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BJ1
Well-known member
Not really - the vac can has a strange and not terribly useful advance curve. Better to get an SVDA dizzy with electronic ignition. I think there's one on offer from Accufire at around £70 all in.
K@rlos
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Are these not alot of good then? I've just brought an OG Bosch one for my bus this week?
Trikky2
Well-known member
vwcamper said:
Working on the assumption the dissy is in good condition :-
If you remove the retard side of the twin vac unit you must leave the vac can connection open whilst you must block off the connection on the carb.
Then set your timing to 7.5 BTDC. Next check your max advance with hoses disconnected (should be around 28 ish (max 30) at 3000+ rpm. Then re check with hose connected and it should increase by around 4 degrees. If your getting these readings then fine.
If the vac can is not giving you around 4 degrees of extra advance you can fit a standard single vac can in its place.
froggy
Well-known member
A DVDA dizzy requires setting at 5 deg AFTER TDC and not at 7.5 deg BTDC like an SVDA.
BJ1
Well-known member
froggy said:
True - but only with both cans connected. A DVDA will work with the rear can open and timed at 7.5 but as I said it has a weird advance curve so the engine will seem a tad gutless. These dizzies were fitted for emissions reasons and I'm not a fan of them. IMO nothing beats a stock SVDA for smooth power with stock carb.
Trikky2
Well-known member
froggy said:
Always a good idea to read the post before posting :lol: :lol:
