currently i'm running an HEI out of a 70's chevy car. my first question is how about a distributor out of a stock 3rd gen. with no advance. i run about 38 degrees of timing. would a " locked out distributor" be too hard to start. i don't have a timing retard.

the main thing i'm dealing with is that i don't have much advance. the engine idles at 1000-1200. and i have the timing light on it and shows like 30 degrees. i go up to 3-4000 rpm and it goes to 38. i put a new curve kit in it and used the light springs and now it jumps all over the place. can't really get a good reading. i use this mainly for drag racing but i drive it often and to the track. this is what i have. 383 srp flat top 2 valve relief pistons with dart 230 iron eagle heads. 2.08-1.60 valves. i run a solid roller cam with about 256-262 at .050. and 630 lift. i just wanna get an idea of what everyone else uses and maybe i got the wieghts on wrong? a pic of how they are on the distributor correctly would be nice. let me hear some feedback.

 

A locked out distributor can be very hard to start, especially on a hot engine.

 

i thought that, but when i get a new box with a start retard i will be putting this disributor back on.

now what could i have done to the advance weights. there is no garuntee that they were on right to start with. they could have been screwed up for years and i just put them back on they way they came off.

 

I ran one of these smaller new style distributors and it worked fine. You only need 2 wires going to it for the magnetic pickup. Install it and set it to full advance. No weights or springs to worry about. The distributor is simply used as a magnetic pickup to collapse the coil field and direct the spark energy to the plugs. If you went to a crank trigger, the distributor would only be used to distribute the spark energy.

My ignition has a built in start retard for up to 20*. I don't normally use it. I have my distributor locked out to 37*.

The downside to the distributor is that it uses a small shaft. When I wanted a bronze gear, the common size ones won't fit.

Buying a recurve kit means knowing what the parts do. You want the ignition curve to be at full advance before 3000 rpm. The weights control how much mechanical advance the distributor gets. The springs control the rpm the advance comes in. They control the speed of the curve. Springs and weights can be swapped around to fine tune. You can have one light and one heavy spring or 2 different sized weights installed. You can even change the center cam to change the curve. Robbing many parts from different HEI distributors gives many options.

Vacuum advance is for part throttle operation. At an idle or WOT, there is no vacuum advance.

You can also lock out the old HEI. Remove the weights and springs and weld the shaft so it doesn't rotate.

 

so the bronze gear on my current dist. won't fit on the newer dist.? and with a locked out dist. you didn't really need a start retard. i'm sure it helps. i just have 11-1 compression. i just want the timing to be stable and consistant.

 

My engine is around 13:1 but I also have a high torque starter to crank it over. I also have a separate ignition switch. I can crank the engine over before turning on the ignition box. That way the engine is turning and priming the cylinders with fuel and has less chance of kicking back. I'll have to go out and see if my ignition has any start retard set into it.

Large cap HEI, small cap HEI and MSD distributors all use a different size shaft.

 

Running a stock direct-drive starter without that ability to delay turning on the ignition often causes the engine to kick back, which a lot of people mistake for "heat-soak".

 

jegs says that they are the same from 1955-1990. don't why they stopped at 90. but i have my old gear. so i'll see if they are any different. i may just throw it in there and try it.

 

1991 they switched to the smaller distributors. I know the MSD distributor is .500" and the small cap HEI is .491". Not sure about the old large cap HEI.

I just went out and checked. My start retard is set at 10* so my timing is retarded 10* when the engine is cranking. Once the rpm goes above 500, it goes back to full advance.

 

just for now i will try to get this mechanical advance working correctly. i will be looking at getting a programmable 7 box and use my distributor that has no advance though. but thats in the future. with that setup i could program my whole timing curve within 100 rpm incriments with a laptop. that would be the ticket.