Hot Rod Forum banner
1 - 14 of 14 Posts

·
Banned
Joined
·
1,533 Posts
Discussion Starter · #1 ·
Hey guys, does anybody know approximately how much to shorten the slots on the advance mechanism to reduce the amount of mechanical advance on the HEI? Can you use epoxy or something similar to that to actually shorten the slots or does it need to be brazed or welded. Thanks.
 

·
Hotrodders.com Moderator
Joined
·
2,783 Posts
slot

If you make the slot .100 shorter you should get about 10 degrees at the crank. I guess you could use jb weld or something but i always weld mine close.

Keith
 

·
The Smell of Nitro in the morn
Joined
·
2,411 Posts
Why ?
If you want to adjust it pick up a new adjustable vacuum advance unit so you can dial it in correctly not to much $ for it.
 

·
Premium Member
Joined
·
3,519 Posts
There should be no vacuum advance for a WOT take off, that's all mechanical. Your vacuum signal at WOT is nil. Initial and mechanical advance are only ever responsable for about 36-38 degrees, anything beyond that is vacuum. If you're pinging at 46 degrees you don't need to mess with your mechanical, just take off part of the partial throttle vacuum with the canister like george is talking about.

K
 

·
Registered
Joined
·
1,161 Posts
jegs has an msd curve kit that has 3 sets of springs and 5 bushins for $10.00.they will also have a diagram with it thatshows you how to use the springs as a set or how to mix them up just as they will with the bushings.there are so many combinations at all different rpm's that you should be able to make something work.i got one with the distributor i bought from them so it should come with the curve kit to.this kit is better than mr. gasket and some of the others.
 

·
The Smell of Nitro in the morn
Joined
·
2,411 Posts
You must be careful when advancing cams.
CompCams has 4* advance machined into them to allow for ware.
So at straight up its 4* advanced, it depends on the cam manuf.
 

·
Race it, Don't rice it!
Joined
·
8,821 Posts
it took off great from a stop, but pinged bad as I got further into it.
There should be no vacuum advance for a WOT take off, that's all mechanical.
I think jmark meant after the car got rolling and the vacuum came up from the reduced load. A sure bet it's the vacuum advancing too much. It goes away after you hammer into it again.
 

·
Banned
Joined
·
1,533 Posts
Discussion Starter · #12 ·
you guys completely over analyzed the question! I want to run more initial advance to get a better mixture burn at lower speeds, better economy, and generally follow the recommendations for my Speed Demon carb. Instead ot telling me the best way to modify my distributor, which is what I asked for, a discussion on advancing the cam ensues! When the thread didn't talk about cams it addressed using springs to change the rate of the advance, not the amount of advance. I am grateful for the replies, they just didn't address the question!!!!
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top