HEI Vacuum Advance Adjustment

[Tynan918]

I bought a brand new HEI distributor and it has an adjustable vacuum canister that I have never touched since I bought it and installed it.

Right now I have my engine base timed at 6 degrees TDC @ 500 (factory specs), and I cannot shut the engine off after a drive without the engine dieseling after I cut it off.

There's no way I'm too far advanced at 6 degrees TDC.

I have recurved the distributor by replacing the factory medium springs with some aftermarket light springs but I have never adjusted the vacuum advance canister and I think that's what's causing my issue of being too far advanced and causing the dieseling..

 

[MonteLS_84]

I bought a brand new HEI distributor and it has an adjustable vacuum canister that I have never touched since I bought it and installed it.

Right now I have my engine base timed at 6 degrees TDC @ 500 (factory specs), and I cannot shut the engine off after a drive without the engine dieseling after I cut it off.

There's no way I'm too far advanced at 6 degrees TDC.

I have recurved the distributor by replacing the factory medium springs with some aftermarket light springs but I have never adjusted the vacuum advance canister and I think that's what's causing my issue of being too far advanced and causing the dieseling..

What is your total timing at? That would matter more than your initial in this regard.

 

[Tynan918]

What is your total timing at? That would matter more than your initial in this regard.

Total timing was set to 36 without vacuum advance connected. Initial Timing with vacuum advance connected at full manifold vacuum is damn near 60° BTDC...in gear RPMs are 700-800 and the car runs great, but diesels at shut off.

I'm told to just disconnect the vacuum advance and set total timing 34 and go up 2° until it pings or backfired at WOT...

 

[airboatgreg]

What is your curb idle speed in drive and neutral? How many miles on engine?

 

[Tynan918]

What is your curb idle speed in drive and neutral? How many miles on engine?

Drive is 700-800 Neutral is 1100-1200

 

[xcookpac]

Lower idle speed. Alternatively. Shut engine off with transmission in gear (and then shift to park).

 

[Tynan918]

Lower idle speed. Alternatively. Shut engine off with transmission in gear (and then shift to park).

Looks like shutting it off in gear is the best option for now...

 

[airboatgreg]

Idle to high in drive. See if vacuum to distributer at idle. If it is move vacuum line to ported vacuum(IE vacuum when throttle is opened) Readjust carb to 600-650 in drive.

 

[Rt Jam]

Your total timing will not have any effect on timing at idle.
What we need to know is what is your ignition timing at idle.

What engine?

 

[SSMonteMan]

Your total timing will not have any effect on timing at idle.
What we need to know is what is your ignition timing at idle.

What engine?

Let's leave this thread dead, lest we call OP back to the forum...

This thread was made before he found out he wiped the cam, so it's kinda unimportant what the engine is... as it's scrap at this point. But, it was a 305.