Easy way to limit the HEI mechanical advance?

[olds307 and 403]

I spent days working on this thing. I decided not to go to the track this time. I had it all ready to go, spent hours doing body work etc, swapping the governor due to issues etc. Noticed the car got slightly hot last run. Pulled up and found one of my belts rolled over and nicked the other one. I found the bolt missing between the alt and power steering bracket. Had to new spare belts, replaced them and the bolt, all is fine. The belt and not being there to recieve my parts was a sign. The Bowtie(yuck) Overdrives governor shifts exactly as said, 4200-4600. I swapped the springs on my other stock governor, was shifting high 3's, low 4's. It shifted from 4600-5000 rpm, perfect. I thought there was a governor sticking issue, so I swapped governors, still has the issues. Regular throttle is fine but full throttle shifts fine but if I let of the gas it drops gears and won't shift back. Pull over and shut off for one second, all is well, shifts fine. I checked the throttle valve when the pan was off no binding noticed when moved by hand. I am switching the governor back at some point but couldn't see anything obivious. Could it be the universal TV cable? The original was cut by the yard. Maybe the Dexron IV, used it, supposed to be superior?

 

[shanghaismith]

Has anyone tried the screw in the plate method?

I used the screw method when I started using nitrous. I limited my mechanical advance to 16 deg. I tapped the plate for a 1/4 -20 slotted set screw and fixed it in place with epoxy. I then ran the engine checked the timing, not enough advance so I used a dremel and took a little off the side of the screw. I kept doing this a little at a time until I had 16 mechanical advance. I now run it at 22 base without the no2 and will drop the base to 18 and try a 150 shot.

 

[olds307 and 403]

Cool, I did the same thing, tapped it out for a cut off 1/4" screw, just never tried it. I have brand new Mallory breakless distributor, had issues with the brand new ballast resistor. I just exchanged the coil to one without the resistor and got a spare module. I bought the set up in April, just bad luck. I can adjust the mechanical from 14 to 24 degrees and adjust the vacuum advance too. It will be a nice track set up when done. I found the throttle cable or valve is sticking, pull over and cable was still extended. Reached in and turned it off, retracted right away,weird.

 

[olds307 and 403]

Mallory ignition in and runs great. Just need to check the curve in the light.

 

[bill]

Just a question..... what would be the advantage/benefit...if any...to using the weights and springs and the vacuum advance from a period correct stock points distributor in a modern aftermarket HEI? Has anyone ever tried it>?

 

[olds307 and 403]

I believe they are different than the later HEI's. The main reason I went with the Mallory set up was tuneable mechanical 14-24 degrees and adjustable vacuum advance too. I couldn't get my HEI in under 3000 rpm, even with the lightest springs. With the lightest springs, 16 degrees in at just over 1500 rpm! Exactly where I want it with my low stall converter.

 

[Intragration]

Yeah, the old points setup won't work with the HEI distributor. Depending on which stock HEI weights and centerplate you have, it's a crapshoot whether they'll do what you want them to. There are many different ones that were available, some will work, some won't. If you're looking for 20 degrees mechanical by 3k RPM, the Moroso weight and spring kit with the lightest springs works great. I used a small piece of aluminum for limiting vacuum advance.

 

[bill]

Yeah, the old points setup won't work with the HEI distributor. Depending on which stock HEI weights and centerplate you have, it's a crapshoot whether they'll do what you want them to. There are many different ones that were available, some will work, some won't. If you're looking for 20 degrees mechanical by 3k RPM, the Moroso weight and spring kit with the lightest springs works great. I used a small piece of aluminum for limiting vacuum advance.

My problem seems to be that the mechanical is too slow and the vacuum is too much for my engine...so I am either setting the initial too low or the engine is running too advanced at speed, killing the power output....I gotta change something.

 

[olds307 and 403]

Have you tried lighter springs and an adjustable vacuum advance canister? I bought this distributor for track gains only.

 

[bill]

Have you tried lighter springs and an adjustable vacuum advance canister? I bought this distributor for track gains only.

Not yet....trying to decide what type/brand of spring kit and whether to use an adjustable or just limit it with a stopper.