I am only getting like 14* of advance out of my mech advance. I just put in an accel mech and vaccuum kit but I think it was the same thing before. I just got a timing light to replace the one that got burned up in my fire. I heard you should get at least 20* out of the stock set-up. any help is much appreciated.

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72 RS,
Vortec 350, LS1 Fans, HEI
GMPP HOT Roller cam, Air-Gap
TCI 700R-4 w/2500 Stall
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You are right! You should have at least 20, preferably around 22, plua the 12-14 initial. I don't know why the heck you are only getting 14, unless you're dizzy is getting worn. I once had a dizzy that gave me FIVE degrees mechanical advance! The pin holes where the weights are were worn slap out!

Is this a factory HEI? I've heard the Summit HEI and another one (the Accel?) have mechanical advances that max out around 14*.

On a stock-type HEI the centrifugal advance is limited by the CENTERPLATE that the tails of the wieghts push against. Most applications came with a centerplate that gave around 20*, but there are "oddballs" out there that can give significantly less- in fact I have one that only gives about 13-14*.

Also to consider: if you have some springs in there that allow the centrifugal to kick in very quickly it's not uncommon to have the centrifugal kicking in partially even at idle speeds. If yours is kicking in 4-6* idling at 800-900 RPMs then that would only leave an apparent 14-16* of advance above that point with a 20* centerplate. It's best to idle the engine down to just about nothing when you set the initial timing just to make sure this isn't happening to you.

I think that might have been happening a little, Damon so I put the stiffest springs in that came in the kit. still only about 14*. The HEI is a stock GM unit I replaced the control module, the vac canister and the flywieghts and center plate all with accel units. the cap and rotor are hypertech and I almost think the rotor might be hitting the underneath limiting the advance. I will try to get a stock replacment tomorrow and see if that helps, any other idea's for when I get it aprt to check tomorrow?

Nah, you're on your way. I'd probably point the finger at the Accell centrifugal advance pieces if I had to take a wild guess from a thousand miles away. Haven't used them myself but just about everything built for the HEI centrifugal advance is crap compared to stock pieces.

Check to make sure the "ribs" underneath of the rotor aren't interfering with the movements of the weights. It'll be the ones that run from tip-to-tail under the rotor (not from screw to screw) that give a problem, if you even have this problem.

If you can dig through some old/stock HEIs and find a #368 centerplate (fairly common, number stamped right on top) that'll give you 20* when used with stock weights. Then you just need the right springs to dial it in where you want it.