:mad: :screwup:

Okay so i checked the initial timing, vac line disconnected and plugged, got 11deg, ran it up to 3500rpm with vac line still plugged, and its only at 16deg, let it back to idle and hooked up the vac line and re-checked it 34deg, why is it only 16deg at 3500 rpm??? :screwup:

don't set the initial.... disconnect the vac line from the dizzy and plug it on the carb screw.

Rev up to 3000 rpm or so and set the timing at 34*.

Lock it down and hook the vac line back up.

Let us know how she runs.

Is it an original HEI distributor? If so, it's VERY common for the centrifugal advance mechanism to wear out and get gummed up with oil sludge coming up the distributor shaft. I've often seen them so bad they give NO centrifugal advance.

A quick check is to pop the cap off and give the rotor a twist. It should move easily against the slight pressure of the centrifugal advance springs then immediately SNAP back to the home position when you let go. That won't check for everything that can wear out, but it's a good first check.

After that, pop off the rotor and look at the springs to make sure they're not mangled, snapped or otherwise screwed up. Then look at the 2 outer advance weights- pay particular attention to where they pivot around their studs- they can wear out rather badly in that area. Holes get like ovals and the studs can get a nasty groove worn in them where the weights ride against them.

All of this can cause centrifugal advance problems.

I'm actually hoping you WILL find a problem with it. Because once you get it fixed you won't beleive how much more power that motor's going to make!

yes it is an hei, i just replaced the vac can because it was so jammed up it was stuck open, so i had the cap off it was very dirty inside, i tried to use some q-tips and brake cleaner to clean it off a little, i have no doubt that i probably need to replace weights and springs, how should i go about cleaning off under the cap, or should i just go ahead and replace the weights and springs, and if so is there a specific kit i should get?? :confused: i will go ahead and re-check everything you said and try to post some pics, thanks

:bowtie:

okay so i got electrical cleaner and cleaned out the inside of the dizzy, got a curve kit and put in the medium springs, replaced the cap and rotor with an MSD cap and rotor. The problem continues, i have it set right now at 16* initial and when we reved up the motor it only advanced to 25* so about 9* initial, we took it up to 3500 and it seemed to be all in at about 3000-3200 i took it up to 4000 just to check that no more came in so now what. should i set it at 36* total which would be about 27* initial and see how it runs or what... i dont have too much $$$ to throw at it right now but i dont want to do any damage to it and i want it to run right

i have it set right now at 16* initial and when we reved up the motor it only advanced to 25*

Correct me if I'm wrong here guys, but total timing is your initial timing + the distributor's mechanical advance.

So, If you'r initial timing is 16*, and your mechanical advance stops advancing past 25*, your total timing is 41* - which is too much intial timing.

Set your initial to somewhere between 9* and 11*. With your 25* of mechanical advance, you should be between 34* and 36* of advance. Play with the intial timing to see where the car drives the best.

Of course, you should have the vacuum advance line plugged at the manifold while you are checking your timing.

using my dial timing light i believe the total timing went to 25*, it was at 16* then when the motor was reved up it advanced 9* so i turned the dial untill it centered on 0 and the dial read 25*, so i think that this is saying 16* initial + 9* mech= 25* total :screwup: and yes the vac line was disconnected and plugged, with the vac line hooked up at idle it reads 36* so 20* of vac advance

what else do i need to check, why do i only have 9* of mech advance, or should i even worry about it, do i just tune it to 27* initial for 36* total but if i do that is that too much initial and with the vac advance at idle it would be 47*?? :eek: :confused: or should i try the lighter springs since looking at the graph those appear to give more advance

Something's limiting the centrifugal advance. Just about any HEI from a V8 should give you about 20* of centrifugal advance (12* initial + 20* centrifugal = 32* total, for example).

I'm wondering if the centrifugal advance plate that rides around the main distributor shaft isn't gummed up. Or the centerplate in the middle of the advance weights is on upside-down.

using my dial timing light i believe the total timing went to 25*, it was at 16* then when the motor was reved up it advanced 9* so i turned the dial untill it centered on 0 and the dial read 25*, so i think that this is saying 16* initial + 9* mech= 25* total :screwup: and yes the vac line was disconnected and plugged, with the vac line hooked up at idle it reads 36* so 20* of vac advance

what else do i need to check, why do i only have 9* of mech advance, or should i even worry about it, do i just tune it to 27* initial for 36* total but if i do that is that too much initial and with the vac advance at idle it would be 47*?? :eek: :confused: or should i try the lighter springs since looking at the graph those appear to give more advance

My dizzy does the same thing. Its totaled out at 36-38* and has somewhere around 22 initial. It like it and runs good. So just leave it high and run it and see how it does.

Something's limiting the centrifugal advance. Just about any HEI from a V8 should give you about 20* of centrifugal advance (12* initial + 20* centrifugal = 32* total, for example).

I'm wondering if the centrifugal advance plate that rides around the main distributor shaft isn't gummed up. Or the centerplate in the middle of the advance weights is on upside-down.

ditto with damon,, the factory weights and center plate should show the numbers facing up on them if i remember correctly. it's been a while. maybe damon can confirm.

there will be a 3 digit number stamped in them. but like said,, make sure they're not upside down,, or on the wrong way for some reason. then spin the rotor plate tangs (where the rotor mount screws go in) with your fingers and make sure that the rotor plate tangs will snap back to the fully closed position when released. then grab the weights and open it from there and release. all should be free to move without sticking on return.

i used to have the number's wrote down for the weights and center plate combo that provided a full 26* of mechanical advance. that way you could use 10* for your initial setting. and with the weight number for the heavier/longer flyweights to bring the advance in quicker. maybe i can find it. but 24* should work fine too with 12* initial. i used to snag every set of weights i could find back in the late 80's when i was at the salvage yards. played arround with all that quite a bit back then.

otherwise you can grind a little bit away to make a more of a radius into the center plate where the sharp, pointed ends of the counter weights are touching the center plate at the later opening stage of mech advance,, to gain a few more degrees of timing at each grind session,, little at a time. the normal old school home curve way there. hard to explain in words. hope it helps.