Bantam Posted October 11, 2012 Share Posted October 11, 2012 What do you have to do to an engine to change from vac dissy to a non vac dissy? Any avantage? Quote Link to comment Share on other sites More sharing options...
KKtrips Posted October 11, 2012 Share Posted October 11, 2012 Block the vacuum hose source and recurve the dizzy. Vacuum advance is only really there to help with fuel economy so as long as you can wind enough timing in (through recurving distributor) and don't mind the resulting fuel economy difference (fark all) then it should be an advantage... Quote Link to comment Share on other sites More sharing options...
Spencer Posted October 11, 2012 Share Posted October 11, 2012 I would never remove it on a street car, only advantage is possibly getting your timing all in quicker with lighter springs in the dizzy as KK says. Thats assuming the dizzy is easily adjustable, Quote Link to comment Share on other sites More sharing options...
Bantam Posted October 11, 2012 Author Share Posted October 11, 2012 Have being given a near new non vac dissy for my Escort, and wondered if it would work. Running 32/36 Weber with the vac hose to dissy Quote Link to comment Share on other sites More sharing options...
Llama Posted October 11, 2012 Share Posted October 11, 2012 As KK said, it just helps with fuel economy at idle and low throttle applications. What type/curve is the new dizzy? Quote Link to comment Share on other sites More sharing options...
ruin41 Posted October 11, 2012 Share Posted October 11, 2012 The vac advance is primarily there to alter the starting timing. For instance if you advance the timing on most v8's to where they perform, even with the vac on it is still a problem to start them when hot. Cranking timing is retarded so it starts and as soon as it gets a vac on it, it advances up to idle correctly. As you go faster the vac advance retards and the weighted internal advance takes over. You have a vacuum there when cruising so removing it will seriously effect your economy as the timing will be permanently retarded. Can be beneficial in some cases like drag cars where they need to know exactly what its doing start to stop and of course one less thing to go wrong. Quote Link to comment Share on other sites More sharing options...
Spencer Posted October 11, 2012 Share Posted October 11, 2012 So yea you can use the non-vacuum dizzy if you want to but vacuum advance can save allot of fuel, you will have to figure this out for yourself If you can get or make the bits to mod a old dizzy the way to set it up is use the softest springs that get your total advance in as early as your motor is happy. Then mod it so your total advance is where you want it, somewhere around 30-32 degrees most likely, probably have to mod the stops if you can to get this sweet. Then try and sort some form of adjustable vacuum advance canister so with your new aggressive spark curve you don’t dial in to much advance at cruise/high vacuum. Realistically this all can be hard to do with a factory dizzy, but can be done, factory setups can be very conservative to deal with all the shit fuel these cars possibly could have been filled up with in the past. So yea Quote Link to comment Share on other sites More sharing options...
Bantam Posted October 12, 2012 Author Share Posted October 12, 2012 Thanks for the answers guys, think I will get new vacuum dissy. Quote Link to comment Share on other sites More sharing options...
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