Fellow FABO's, I have a 440 RR and when cruizing down the road, the car flutters and spits and back fires a little. A friend said that the vacuum advance needed adjusted. Sure enough I un hosed the vacuum advance and it was my problem. Which way do you go with the adj screw in the vacuum nozell? Out or in to lessen the vacuum. And is there a procedure to this or just hit and miss? Thanks for any tech talk info.
Vacuum Advance Adjustment Help
- Thread starter dusty1
- Start date
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Mrmopartech
Well-Known Member
Do you have a electronic ignition system in the car?What is the intial timing set at,what is the total timing at 2200rpm,what coil are you using,what cam is in the car and the vacumn at idle and in drive,mrmopartech 450 424 0445/514 659 0445
ken5124
65 Valiant Signet
Doesn't the adjustment in the vacuum canister only adjust at how many inches of vacuum it starts to operate.??
C130 Chief
Mechanical Genius
If you do not also have a light throttle ping/detonation, you may have a reasonable amount of advance. The problem may be due to distributor phasing. Some of the MP distributors had this problem.
.............The pick up in the dist is usually bad if ur base timing is right....and u have the vacc line off................check with a multi meter, it should read infinity......................kim.....
dgc333
Well-Known Member
It adjusts the preload on the spring that pushes the arm back to the zero position. So by increasing the preload it increases the amount of vacuum required to start the advance moving and hence the total amount of vacuum required for full stroke. The amount of advance that can be provided is controlled by a mechanical stop on the arm and is stamped on the arm in cam dregrees so you double it for crank degrees.
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