distributor help

83toybeater · Post by **83toybeater** » Wed Nov 07, 2007 10:41 pm

ok i think i found out why i have had such a hard time with drivabilty and performance on my 83. its a 4ac with a weber.

question
does anyone know if the dissy is a 2 stage distributor? where one of the ports runs off of manifold vac, and the other off throttle vac? and also what one does what?

i have always had vac going to the top port, today i realised that my dissy isnt even responding to vac advance.

please input needed asap, as im gona put a new dissy in tomarow

takza · Post by **takza** » Thu Nov 08, 2007 2:47 am

There are 2 and 3 port dists...only one is needed for advance. Just test the one you want to use to be sure it advances the plate?

83toybeater · Post by **83toybeater** » Thu Nov 08, 2007 7:27 pm

ok i put the new dissy in today, well not new its probly 25 years old butanyways it works correctly.

i put a a vacuume tester up to the 2 ports on the new one, the top one advances it a little, the lower alot. me and the tech at my work agree that it is a 2 step adance distributor. the top one runs off of manifold vacuume, the bottom runs of throttle vac. based on how they move it makes perfect sense to me

can someone correct me if im wrong?

ps my old dissy both of them didnt advance it at all

Typrus · Post by **Typrus** » Sat Nov 10, 2007 2:54 pm

Yup. One gets full mannie vac the other gets ported vac. The little vac port above the throttle plates I believe....

takza · Post by **takza** » Sun Nov 11, 2007 2:54 am

That upper port also runs the EGR thru the vac modulator?

83toybeater · Post by **83toybeater** » Sun Nov 11, 2007 10:12 am

it has a weber on it, where do i find throttle vac, the port on it seams to be manifold vac.

takza · Post by **takza** » Mon Nov 12, 2007 5:14 am

I think you want full manifold vac?

83toybeater · Post by **83toybeater** » Mon Nov 12, 2007 9:17 am

i need both, the manifold vac advances it once the car is started, throttle vac is for when you get on the throttle.

we put a vac tester to each of the ports, the top port only adv a little, the bottom advances alot, there fore top is manifold, bottom throttle

coming out of the weber is constant vac, so that leads me to belive its manifold.

takza · Post by **takza** » Tue Nov 13, 2007 2:19 am

Basically all you need is manifold vac advance at idle and centrifugal advance at higher speeds?

The R port (partial vac) is related to the emissions stuff...such as the EGR, etc?

83toybeater · Post by **83toybeater** » Tue Nov 13, 2007 1:13 pm

what one is the R port?