hey guys I installed a Moroso advance timing curve kit, using the lighty duty springs here is my timing graph

rpm adv.
700 -17 (no advance, inital setting with dist.)
900 -25(this is where I'm having problems dont want it to START at this maybe just above this one
1100-27
1400-30
1700-33
2200-35
2450-38(max's out here)

I notice while giving it gas past 2450 rpm the timing goes down a little bit?

also what needs to be modified to make the curve come in not as soon of rpm, I like the slope. just not when it comes in. another 200 rpm higher and I would be happy. as it seems my barry grant demon does NOT want to idle anything lower than that, I can pull the throttle back to 700rpm but using the screw, there is something which isn't allowing the throttle to have the car idle lower than 900

anyone have any experience with customizing the wieights and center pieces? I'm thinking I might need to ADD material via welding and grindign smooth at the point ends of the center peice.

cheers

blake

ps this is on an non ECM HEI

 

I have found using one light and one heavy spring on mine works the best. Just experiment wit diff springs till you find what works for you.

 

thanks for the reply, I alredy tried using a light spring and a med spring. I might try one of the old light springs as they seem perhaps a tad stiffer than the aftermarket springs.

I know you can alter the curve by shaping the center weight

 

That is why I love my EPROM burner. Instant changes, no guess work involved.

Almost like me still trying to get my transmission governor to shift at the right place.

You have to balance the spring and the weight to get what you want.

Really though the light springs are hurting you. Unless you have really light weights they let the timing advance very early. I found that my small engine in a heavy vehicle with tall gears really liked alot of timing. You really should get your max advance in by about 2,800-3,200 rpm tough. On my old carbed 305 it was 18* initial timing, 20* centrifical @ 2,800 (stock weights, 1 heavy and 1 light springs, and limited travel), and 10 @ 10" manifold vacuum advance. It ran really well on the stock 305 cam, then I turned around and used the same setup on my XE-274 cam. It had decent off-idle part-throttle response (big cam and stock converter), decent mileage, and good top-end power. I had a little difficulty in hot starts after being on the highway for a while, but that was fixed by adding in an ignition kill switch. Make sure the switch is off, hit the starter, engine cranks over normlly, then flip the switch on and the engine fires up. No RURURURURURURU Vroom like you would normally experience.

 

The timing goes down at a certain rpm range, since the manifold vacuum drops and the vacuum advance lessons out a little to preserve fuel economy. The only way to adjust it is to get an adjustable advance or modify the advance arm (there's guides to be found using google).