Team Chevelle banner
1 - 14 of 14 Posts

·
Registered
Joined
·
3,030 Posts
Discussion Starter · #1 ·
Just wonderin'... I ended up getting an MSD 8360 mechanical stuff distributor instead of the 8394 with electrical stuff. So now I am playing with colored bushings for advance, which I don't mind at all. At least I can see it!

Anyway, I have a 21 degree bushing in it now, going from 17 to 38 degrees. Hooking up my MityVac to the vacuum canister, the idle speed goes up when I start to pull in vacuum and raise the timing. Soooo.... them the motor is producing more RPM with the same throttle plate setting. It seems happier with a titch more idle advance. Should I put in the 18 degree bushing and go 20 to 38, if the starter doesn't mind? I am only 9.6:1, reduced by 4200' of altitude. If the starter cares, how will it tell you? No crank? Slow crank? Creepy noises?
 

·
Registered
Joined
·
7,729 Posts
Usually you need to advance the initial to get a cleaner idle, thats the main purpose.
I don't think you will need to put the 18 degree bushing.
But to answer your question it should start ok no porblem at 20 degrees base.
A common symton of over initial timing is slow cranking or starting kicking back.


Dave
 

·
Registered
Joined
·
18,906 Posts
i don't see why not.. and since your motor likes the vacuum advance at idle (i think every engine does), then hook that up to full manifold vacuum and tune the carb around that. you might wind up with a carb that has the throttle blades pretty much totally closed at idle, but that's a good thing and means that the carb will be totally running on the idle circuit at idle and also means less throttle opening at cruising speed- which means better throttle response and miles per gallon.

just don't freak out when you see 40-something degrees of advance at idle when you hook the timing light up.. that's ok- that's what the vacuum advance is for.
 

·
Premium Member
Joined
·
1,292 Posts
I got the 10 and 14 bushings from this site that was recommended to me by someone here. You can barely tell them apart, but the 10 doesn't quite fit without a little clearancing. The 14 drops right in. If you're running 38 total, you could have the initial at 24-28 with these. I was told to try 2 deg advance increments and see if it starts ok after letting it warm up and then shut down. When you get to the point the starter kicks back, back off on the advance a couple and you can then more accurately know how much initial your motor would like. Even though this might be helpful, I think you'd be fine with 20 initial and the 18 deg bushings. If you ever determine you want to drop the total advance a couple, then something like the 14 might be perfect.

http://4secondsflat.com/MSD Distributor Tuning.htm


Also, you might want to be careful with the vacuum advance. I know my 8361 came with a can that added way too much for my combo. My combo worked much better with the 14 bushing and no vac adv than it did with the 18 bushing and msd vac adv. I have an accel adjustable vac adv in there now that seems to work great.
 

·
Premium Member
Joined
·
1,544 Posts
Just wonderin'... I ended up getting an MSD 8360 mechanical stuff distributor instead of the 8394 with electrical stuff. So now I am playing with colored bushings for advance, which I don't mind at all. At least I can see it!

Anyway, I have a 21 degree bushing in it now, going from 17 to 38 degrees. Hooking up my MityVac to the vacuum canister, the idle speed goes up when I start to pull in vacuum and raise the timing. Soooo.... them the motor is producing more RPM with the same throttle plate setting. It seems happier with a titch more idle advance. Should I put in the 18 degree bushing and go 20 to 38, if the starter doesn't mind? I am only 9.6:1, reduced by 4200' of altitude. If the starter cares, how will it tell you? No crank? Slow crank? Creepy noises?
Hey Gibbons, I just got an MSD 8360 for the rev limiter. I have mine running great but my rev limiter isn't setting correctly. Is yours? If so, what ground source did you use to ground the grey coil wire while setting it?

The IGN 101 article on this board somewhere says adding manifold vacuum adv can add 15 degrees at idle, so just heads up with that in case you have detonation or pinging.
 

·
Registered
Joined
·
6,347 Posts
i run 24* initial with 38 total with vac advance with a 10:1 355 and big old stock style starter. no issues at all.

i also ran it locked out at 36* plus vac advance.

aaron
 

·
Registered
Joined
·
3,030 Posts
Discussion Starter · #9 ·
Gee, thanks Todd, make fun of my cam :D Dumb question time: What does the cam have to do with it? Compression I can see....

Sergio, I also got a Digital 6AL, so I will be using its rev limiter and haven't played with the distributor's rev limiter. I am wired to my Blaster SS coil just like the instruction schematics and it and the tach work fine. I am going to get another 3 pin weatherpack connector, and hook up to my 6AL with it. That way, if it ever fails, I can switch the plug back to my distributor and be on my merry way.

Mark, those are wild bushings! There's one of everything out there if you know where to find it!
 

·
Premium Member
Joined
·
2,061 Posts
Your engine is more likely around 9:1 btw. I had mine measured and just like they say, it was an 9:1 compression engine. It leaves to much on the table if you ask me. as a side note..
My weights where stuck last summer, took a while before I notcied and learned how to adjust ignition properly, it was locked out at 30 degrees plus only a couple of degrees in vacuum, my starter kicked back a lot and I´m emberassed to say I changed that starter 5-6 times before I fixed the ignition. That was with the stock ZZ502 starter.
I know where too look know if it happens again, learnt the hard way.
 

·
Premium Member
Joined
·
1,544 Posts
Sergio, I also got a Digital 6AL, so I will be using its rev limiter and haven't played with the distributor's rev limiter. I am wired to my Blaster SS coil just like the instruction schematics and it and the tach work fine. I am going to get another 3 pin weatherpack connector, and hook up to my 6AL with it. That way, if it ever fails, I can switch the plug back to my distributor and be on my merry way.
10-4. I might have to go that route. Good luck man :thumbsup:
 

·
Registered
Joined
·
314 Posts
I have a big cam with alot of overlap, comp cam 292h... I run the 14 deg. bushing mentioned above from 4secondsflat. I run 22-23 deg. initial, 800 rpm idle with a stick shift. It works great with that cam. Nice clean idle. No kickback, etc... Make sure to check the car when it is heat soaked, that is when it will run on, etc...
 
1 - 14 of 14 Posts
Top