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vacuum advance a15


81sunnyson

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ok

 

car has had issues from the begining but im finally addressing

 

fixed burnt valve and restored compression

 

added new pcv

 

carb is shot pretty much but gets me up the road

 

set timing as best as possible but not getting any vacuum advance ....maybe because idle is so high

 

at what rpm does the engine stop making vaccuum?

 

other the the brake booster line, where can i get direct intake vacuum ?

 

eventually plan to do egr delete and add weber or possible cv carb...so  any pointers?

 

all vacuum hoses were re-routed to spec

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set timing as best as possible but not getting any vacuum advance ....maybe because idle is so high

 

at what rpm does the engine stop making vaccuum?

Use or borrow a proper timing light. Guessing is no good and the idle mixture and speed can't be set properly if not.

 

Vacuum for the advance comes from a port on the side of the carburetor which is just slightly above the throttle plate. At the correct idle speed (about 650-750) there is no vacuum. When the throttle is opened the throttle plate rises above the port and applies intake vacuum to the distributor. Vacuum in the intake is a function of how far open the throttle is, not RPMs. Full throttle is 5 inches of vacuum or less. Vacuum advance is for above idle and part throttle only to improve mileage and dive ability.

 

 

other the the brake booster line, where can i get direct intake vacuum ?

For vacuum advance don't do this use the port on the carb

 

eventually plan to do egr delete and add weber or possible cv carb...so  any pointers?

 

all vacuum hoses were re-routed to spec

ERG delete is a waste of time. You can do if you wish but there are no performance gains at all. EGR is only working above idle, when the engine is warmed up and is not working at full throttle. If not working at full throttle you are getting everything the engine is making.

 

 

as far as idle....dies at 1000rpm

Are you saying it dies if you try to adjust below 1,000????

 

 

Causes of fast idle or inability to turn down

 

1/ choke stuck on or part on. Possibly auto choke not working. Linkage stuck, Alt. not charging

2/ throttle cable too tight.

3/ idle speed screw incorrectly adjusted

4/ timing too advanced

5/ secondary throttle stuck part open, not closed fully

6/ primary throttle shaft worn into carburetor body. Throttle plate rubs case and sticks.

7/ Idle cut solenoid not working or not powered. Fuel to idle circuit shut off.

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