vacuum problem?

[Anonymous]

OK.
Heres my problem.
my car will idle and accelerate fine. But trying to hold speed 30+MPH it stutters, never stalls, just occasionally stutters. If I accelerate it smooths out, but hold it at speed and it comes right back.
From reading through the other post, I think it may be the vacuum canister on the Dizzy, I have removed it, and tested using a very precise instrument, my mouth. If I apply suction, slowly the air passes right through, apply a quick suck and if actuates the rod,
Is this a problem?
So if I need to buy a new canister or distributor, can I or should I buy a duraspark II?
I seen that recommended else where here, but not sure what to get, The Dizzy is only 2 years old as I bought it when I bought the new rebuilt motor, dont remeber if a new vacuum canister came with it or if it was off the old unit.
eiither way, should I buy a new DSII or just find a new canister?
thanks in advance.
george.

 

[MustangSix]

Sounds like a leak in the diaphragm, and that can cause the symptom you describe.

Simplest thing is to replace the diaphragm. Takes 10 minutes and is cheap.

Best thing is a DSI or II. Some will tell you that you have to change the carb because of the way the ported vacuum is routed, but I initially ran mine with a stock Autolite 1100 and had no real problems with it. I'd use a Mopar or GM module if I were doing it again. Simpler, cheaper.

 

[Anonymous]

lucky me, I am a bit of a packrat. I happened to have the old Dizzy and vacuum canister, It was still is good condition. I replaced the part, reset the timing, idle, and air/fuel mixture, and Finally after almost 2 years the car runs smooth.
As I reviewed the series of problems and my hit/miss strategy for fixing them it is amazing I did not give the car a 45 CAL. lead injection from my Colt.
I believe the problem began by putting the old SPUN balancer on the new motor, then not being able to set the timing, I put on a new distributer, this of course had the bad vacuum advance, which only added to my frustrations. I then went on to replaced every other component I thought could be the problem, plugs, wires, coil, carb...ect... all with mixed results, but never a solution. Now, finally things are right in the world.
I want to thank everyone here, both for the direct post to me and the other posts that allowed me to gain some knowledge in the cause and effects of particular parts. I look forward to being able to help others through my experience.
Soon, HEADERS and a 2bl carb upgrade
george.