MSD and timing question

Buzzmobile · #1 (**permalink**) 06-22-2005, 08:58 AM

If you can help, thanks in advance. I am in a pickle here. I need to know the procedure for setting the idle advance with the MSD mechanical advance. I know how to set the total advance, but specifically..... if I want to raise or drop my idle advance, and not want to change my total advance, how do I do that?

THanks
Buzz

scottj · #2 (**permalink**) 06-22-2005, 09:12 AM

The bushings limit the degrees of mechanical advance. To increase base timing, change to a bushing that allows less advance and re-time the engine back to the correct total advance.

The springs affect when the advance comes in.

Scott

HighPlainsDrifter · #3 (**permalink**) 06-22-2005, 09:21 AM

Buzz,
Set your idle timing by loosening the dist base nut and rotating the dist clockwise[ advance] as you look at the timing marks with the timing light.Set it to 16*,tighten base nut. Now take of the dist top ,engine not running, and rotor. Find the mechanical weight springs and see what they are,light,medium or heavy,probably colored black,silver and so on. You would get an assortment in a msd spring kit and now put in one step heavier. Most stock dist are set for 28* mechanical advance, next step down would be 24*, then 20*.Try and get the 20* set of springs and install them. Put everything back to gether and run engine at 3000 rpm and see if timing is 36 to 38* total advance[ 16* initial and the 20* mechanical] You may have to change spring a couple times to get it correct.
Perry.

392cobra · #4 (**permalink**) 06-22-2005, 09:48 AM

Scott got it right.

Amount of centrifugal advance
red bushing = 28* blue = 21*
silver = 25* black = 18*

Subtract from your total advance gives you the initial advance.

The springs determine how quick,the starting point and slope.

scottj · #5 (**permalink**) 06-22-2005, 09:54 AM

Go to this link. As always, these guys seem to have a pretty good handle on this stuff and can explain it better than me. Not to mention, I don't have an advance curve at all, so my advise is suspect at best.

http://www.msdignition.com/dist_mechadv.htm

Buzzmobile · #6 (**permalink**) 06-22-2005, 01:48 PM

OK, I am stuck again. I did the removal of the cap and the rotor to see what I had. I was looking at the bushing set up and couldn't decide if what I was looking at is the bushing or not. So I unscrew the lock washer on the under side of the advance assembly. And as I am unscrewing, the thing jumps and dissapears! F***! Ok, I go down and get a new advance kit ...and now I open it up and look. I see the bushings, springs, 2 washers and 2 lock nuts. OK, cool. Well, I don't see how the thing goes back to gether...like where are the threads?! So I take the other side off, now knowing to hold on. Well I get it out, and the lock nut is a much larger than the one in the kit I got. And I still cannot tell what it "screwed" into? I am not seeing it! I know this sounds stupid, but I have never been into this system before and am new at this.

Buzz

TC Cobra · #7 (**permalink**) 06-22-2005, 02:22 PM

Hey Buzz!

Not sure what you're taking off and how it could "jump and disappear". Or, what the "other side" is.

There is only one advance stop bushing. It is located on the underside of the advance mechanism - a vertical pin, 3/16" in diameter, about half way between the two rotor screw holes. It's hard to see and even harder to get to unless you also remove the "plastic" base of the distributor (two allen screws). The locknut holding the bushing on is about 5/16" in size and fits on with a small washer between it and the bushing itself.

When installed correctly, the bushing fits into a small "pocket" in the mechanism and is basically flush with the underside of the mechanism.

Hope this helps!
Dwain

Buzzmobile · #8 (**permalink**) 06-22-2005, 03:25 PM

OK, I am an ass! I love learning, but this just seems like the long way around. Here is what I did. I went and looked at the instructions and on the diagram, there is an arrow showing where the bushing mounting site is. It happens to curve right over the nut that is embedded in the mechanism that accepts the rotor screws. OK, you guessed it. I quickly looked at the pic, thought ok...those nuts are where it goes. Started to take the first off and when it let go, it dropped and I lost it (hence the "jump" referrence...kinda like humor, only different). Well, I thought I was missing something in the kit or didn't understand how that worked holding a bushing, so YEAP! you gessed it. I took the other one out! Didn't lose it, but now I took out a pressed on part. MSD tech line got me straight and they are sending me 2 nuts to put back in. And I still have no idea what bushing I have in there cause I am so pissed at my self, I refuse to go back into the garage. Thanks for helping the newbie! I am getting a little frustrated. This is EXACTLY what I was trying to avoid problems by BUYING a dyno tuned and tested engine complete and just drop it in and go. Didn't work out that way and now I have paid the price for that service and now I am doing it my self...and poorly at that. I know my limitations and that is why I went the way I did with the engine.... I am terrible at tuning a carb and now have proven poor at distributor work. Some frustration showing!!!!

Buzzmobile · #9 (**permalink**) 06-22-2005, 05:16 PM

Ok, so now let me get this straight. If I want to run 38 degrees total and I used the black bushing (18), my base timing would be 20 degrees...correct? I would set the total advance with high RPM at 38 degrees, and the initial timing should be 20, controled by the bushing choice.

What should I want as initial advance? I know what I need at total.

thanks
Buzz

392cobra · #10 (**permalink**) 06-22-2005, 05:32 PM

Correct.

18* cent. plus 20* initial = 38*

That should be fine Buzz. Did you get rid of the heavy springs ??

Now get it all in around 2,500 rpm and you'll see a big difference from before.

TC Cobra · #11 (**permalink**) 06-22-2005, 05:56 PM

Hey Buzz!

Don't be so hard on yourself. We've all had our share of "learning experiences" with these projects. That's just the way it works sometimes - and that's part of the "fun". ;-)

Sounds like the MSD tech shed some light on your issue and a resolution is close at hand.

Good luck!
Dwain

Buzzmobile · #12 (**permalink**) 06-22-2005, 06:09 PM

thanks guys for the support! You wouldn't know by my posts that actually I do have some sense. And believe it or not, people literally put their lives in my hands every day....but distributor...well, that is hosed

Vascular stent....biopsy the mass 15 cm in the chest...hey, I am all over that. Infact, I feel much more comfortable doing that than worrying about messing up this engine.

MSD did a nice job and the guy on the phone knew that I was frustrated and just took it one step at a time until we figured out how stupid I was...then he said...this is the replacement part (2 nuts for the rotor bolts)...then the parts lady said...just give me your address and I'll send them to you. No charge. She took pity on me and they were a couple of buck for the pair and she could not bring herself to charge me. So support MSD and buy all their stuff! Still don't know what the bushing is in the car. Still haven't gone out to the garage to look.

Springs are one silver (smaller of the two) and one blue

thanks guys

Buzz