[vette427-sbc]

after aquiring a tach drive, i rebuilt it and it ran great. (thanks to B2B) BUT when i timed it (vaccum advance pluged up) i got no mechanical advance. when the vaccum adcance was hooked up, i did get some advance, but not as much as i should be getting with both the mechanical and vaccum.
the previous owner of the distributor had some rotten rubber bushing on the mechanical advance limiter (which i tossed when during the rebuild). i changed this to a copper one from a Mr Gasket kit which still allowed the mechanical advance to move, but much less than before. can i run a dizzy with no bushing? or what else would you recomend i do

 

[SIXFOOTER]

i got nothing to add other than it sounds like it neds some kind of bushing, can you drill out the copper one to allow more movement?

 

[big2bird]

after aquiring a tach drive, i rebuilt it and it ran great. (thanks to B2B) BUT when i timed it (vaccum advance pluged up) i got no mechanical advance. when the vaccum adcance was hooked up, i did get some advance, but not as much as i should be getting with both the mechanical and vaccum.
the previous owner of the distributor had some rotten rubber bushing on the mechanical advance limiter (which i tossed when during the rebuild). i changed this to a copper one from a Mr Gasket kit which still allowed the mechanical advance to move, but much less than before. can i run a dizzy with no bushing? or what else would you recomend i do

I sure hope this is not one of mine. :laughing:

Sounds like I just advised on this one.

Without a picture, and you saying no mech advance,my best guess is you have the weights on upside down/backwards.

 

[TimAT]

IMHO, the trick to setting up an advance curve is to get the advance to start coming in about 1500, then stop at 3000. At 3k you want our total advance 34-36*. It takes some effort to get there. You may have to reshape the bushing or the slot it runs in. Usually, changing the bushing, and using the correct springs will take care of it.

Look for Lars' sticky about timing. Should have all the info you need..

:cheers:

 

[big2bird]

Look at the weight layout in this pic. Look right?

 

[vette427-sbc]

im pretty sure the weights are set up correctly. i can move them to simulate the centrifugal force and it moves the rotor counterclockwise (CCW=advance, no?).
i had an entire Mr. Gasket kit on it before i took it off. the springs seemed REALLY soft and i wondered if maybe the weights were already giving it full advance at idle, which it being at idle i had set a 12*

as for the bushing, it seems like any bushing severely limits advance

 

[SIXFOOTER]

Put a rubber band on the weights and then set your initial and idle mix. Then remove the rubber band and do the rest. If the timing changes when you remove the rubber band at idle then the springs are to soft

 

[vette427-sbc]

Put a rubber band on the weights and then set your initial and idle mix. Then remove the rubber band and do the rest. If the timing changes when you remove the rubber band at idle then the springs are to soft

good tip, thanks

 

[big2bird]

im pretty sure the weights are set up correctly. i can move them to simulate the centrifugal force and it moves the rotor counterclockwise (CCW=advance, no?).
i had an entire Mr. Gasket kit on it before i took it off. the springs seemed REALLY soft and i wondered if maybe the weights were already giving it full advance at idle, which it being at idle i had set a 12*

as for the bushing, it seems like any bushing severely limits advance

Post the # of the kit you used.

 

[vette427-sbc]

http://store.summitracing.com/partdetail.asp?part=MRG-925G&autoview=sku

the weights would not fit so i used those springs with the stock weights

 

[big2bird]

http://store.summitracing.com/partdetail.asp?part=MRG-925G&autoview=sku

the weights would not fit so i used those springs with the stock weights

Wrong stuff. There's the problem. Purchase Mr Gasket # 928G. Use that bushing. Use 1 black/1 silver spring. Use the stock weights. Throw that crap away.:thumbsup:

 

[vette427-sbc]

are the black springs in that kit the same as the black springs in the kit you recomend?
also, should weights limit how far back (as in the opposite of advancing) the stud slides in its slot. with my weights on, the stud kind of hangs out in the middle of the slot.

 

[big2bird]

are the black springs in that kit the same as the black springs in the kit you recomend?
also, should weights limit how far back (as in the opposite of advancing) the stud slides in its slot. with my weights on, the stud kind of hangs out in the middle of the slot.

I can only tell you the kit you bought has springs designed for those weights. Since they don't fit, they are wrong. I AM sure by your symptoms they are too weak. Buy the Mr Gasket kit. It works. I have rebuilt/recurved too many of these units. I use Lars formula. It works every time. Use the stock weights. All the aftermarket weights DO NOT work for crap.

 

[big2bird]

The stop bushing determines the total mech advance, not the weights.

 

[vette427-sbc]

The stop bushing determines the total mech advance, not the weights.

i have the stock weights on it and they limit how far back it goes, not how much advance it gets