Yes you can change it but go back to post#29 and buy that kit.

 

yeah, I got confused and was thinking that was YOUR post experimenting with the 098 that you had, rather than driver actually posting what he discovered on his own.
sorry, brain fart........

 

You lost me there for a second and had to go back and read----I didnt realize you were talking to me I was just noting the addition of 10*and that you can alter that a little by thinner walled bushings.Sounds like he is good providing it doesnt ping.

 

I didn't read every post; however, I'm sure that a few members have given adequate information.

The first thing I would suggest in this case is to see how much mechanical advance is built into the distributor. Restrict the weight with rubber bands so they don't provide any advance. Then remove the rubber bands and also remove the springs. Take another reading. The difference will be the total mechanical advance. Without springs the distributor may be too far advanced to start. The weights will fling out right away. If the car won't start, then repeat the first step and drop the timing down 10*. Let say in the second case with rubber bands your timing reads 2*. Without springs it reads 18*. You now know the mechanical advance is 16*. If you set total timing to 38* with springs, the lowest intial will be 22*, it can't be any lower than that in this example. Unless you change the amount of the mechanical advance, it is what it is. Some have mentioned what needs to be done. As for the mechanical advance, there are 3 things that affect it; springs, weight, and rpms. After a certain rpm, increasing rpms will have no affect. Tuning the curve is done with springs and weights. Most tuning can be done by changing the springs. If heavy springs are used and it is stilling coming in too soon, then lighter weights will be needed. You'll also need to check to see if the mechanical is coming in a idle. To do this, use the rubber bands to keep the weights tied back. Take a reading. Then remove the rubber bands. If you timing is increased, then the mechanical advance is starting to come in at idle.

Contrary to someone else post(s), intial timing is not the big concern. Don't get me wrong, it has to be within reason. You want the total timing (intial and mechanical) to be about 34*-38*. Initail should typically be 8*-16*. The intial is just a reference point. Once you know where it falls, you can then use this number in the future. It eliminates having to rev the engine up in the future.
It is difficult to know whether your engine will run better at 34*, 36* or 38* timing. A dyno would be helpful. To say every engine needs 38* goes too far. Modern fast burn heads tend to need less timing than some of the older heads.

 

I've got that kit already installed. I thought the spring & weight kit only changed the advance curve, not the total advance available. If my distributor has only 18* of mech. advance, how do I get more with the spring/weight kit?

Thanks, only takes me a dozen times to understand something.

 

Capt I'm not 100% sure but I think your kit comes with 2 bushings that changes the limit-those bushings are under the center plate that is held down by the 2 c-clips-2 of the bushings in your kit have a shoulder they go in the weights and the other 2 are are your limits bushings--I think-pretty sure-I better go tear one apart !!!

 

OK, that's the bushings you were talking about. Guess I better go see if I saved any of those parts!

Thanks for your help, think I finally get it. I'll let you know results.

 

Hold on Capt I was wrong-those bushings under the plate are actually studs not removable bushings-looks like the limitations are in the cam that sits between the weights-I'm not sure how to increase your cent. unless maybe they make other cams or you modify your cam but I wouldnt do that yet-and then I'm not sure that under the plate the slots there might limit it completly-again you could make the slots longer-but not advisable-Lets wait and see if other members will chime in with some input on second thought just start another thread about this subject and see if we can get some info

 

You're right. There are 2 sets of bushings, but they are evidently for the 2 different size pins. I'm going to start over again from step 1 and just live with what I get. The car is so original, I hate to change distributors or modify my existing one. I may not be getting all the vac. advance I should, only 9* as best I can tell. I'll look into that and read Lars' paper again on vacuum.

Thanks for all your input and help.

 

OK I went out and did some more checking-the slots under the plate will give you almost 25*dist thats 50*at the crank-so dont worry about the slots-If you want to modify -then modify your advance curve kit-If you look down on the top of your weights you can see where they would they stop the advance-by shortening the pointed end of the weight it will allow more advance as long as it doesnt bottom on inside of rotor.One other thing one of the other members said later model heads dont need as much advance-OK I'm done that grass is not gonna cut itself !!!!

 

Capt Shark,

just wanted to give you an update that the '72 really runs very nice now. especially noticable in the 3500 - 5500 rpm band. Capt Shark, you might want to try what I did, and just remove the bushing altogether. I have the same mechanical advance specs as you have on your dist - 18*, and removing the bushing gave me about 8* more, which is perfect.
I had originally set my full advance to 38* and "let the initial fall where it may"(before removing the bushing), but felt that 20* initial was just a little to much for my comfort. Now I'm at 12* initial with my 26* mechanical for a total of 38*, which is exactly what i wanted

 

OK, I'll try that and see. Next weekend's project.

Thanks again, glad you got your's straightened out.

 

Driver:
Where are the bushings that you removed from the distributor located exactly? I have same distributor as yours from a 72.
Thanks