That's too funny, good for you!

~900. It will idle much lower, but I've got it there because I know it will drop some in gear. I guess I will go out tomorrow evening and pull a couple of the easier accessible plugs.

Dumping off the vac can would solve the problem...or would it? If I went with 16 init and had 30 mech (which I cant sem to do anything about), I wouild still be at 46...

Whats the cons of dumping the vac can? Obviously its there for a reason...

BTW, I did search Norvals threads and saw where he did fabricate some kind of mech stop, but found no description. I emailed him, well see if he answers.

 

Wow! sold at buy it now price of $899 @ 5:30 this morning. Must have priced it too cheap. Who would have thought that 30+ years ago when I pulled it out. Sorry to step on your thread. TTT for you!

 

Dayum- Lucky you!

Its OK, I dont think the thread is going anywhere. Ill wait and see if Norval or Lars answers my emails for a couple days, give the problem to a girl that is in a couple of my classes that has a dad that builds hot rods, and after that I guess I am buying a dizzy. But you can be sure that after that I am going to take this one apart into tiny little peices so I can have an understanding of whats going on. I hate having to throw more money at this car, Ive got way too much in it already.

I wonder how it was ever running before and survived with that much advance...because the previous motor lived a long life with this same setup.....

 

Now that's pretty wild.
I had a set of Z28 302 heads 1967 only, date coded, in used, but slap on shape and couldn't get any interest in them, gave them away less than 2 weeks ago.



Before you spend a bunch of money.
Try flipping the centerpiece over (numbers don't matter) and see what you get. Try it with the original too.
You can also mix and match the weights.

Easy to do with the distributer out of the engine, lock the shaft at the gear with tape, mark points on the cap lip (housing) with markers and play around. That will show you how it works and you will see if the advance is reduced, then you can install and read advance accurately with a lite.

Like 63mako said 18 is nice, but not written in stone.

 

I tried flipping it over previously; it stops the weights from fully retracting that way. Good idea though, on the right path. I need a way to keep them from deploying all the way. Other edge of the center plate.

I still cant understand why it is giving me 30* if the center plate is right and the center plate is in fact what determines it.

Any more thoughts on using the 5-pin module? That would be a simple fix and I think I can get one for about $35 now...

 

Gm did this with the centerplate and weights.

What was the estimated or real total centrifical advance with the centerplate turned over and the old weights?
If you thought it stopped it from retracting, then the advance must have been reduced.

Or post a pic.

 

Sorry, I think I was less then clear.

1. Never checked the old timing, the PO told me it was good and it seemed that way, so I never worried about it. It ran great (until I threw my blower belt one day. When I put on the new blower belt it was tighter and boost went from 7-8 psi to about 10 until a piston broke.).

2. Tossed that block and rotating assembly and replaced it with 383 short block. All other components are the same.

3. Upon setting up the new motor I noticed my mech adv was coming in way too late and seemed way too high, so I went out and bought the spring/weight kit.

4. When I got the new weights and center plate, I examined the center plates to make sure they were the same and followed the directions closely as to its orientation, because it is to be flipped upside down for counterclockwise rotating dizzy. I tried it upside down, just as a check to see, and thats when I saw that the weights could never fully retract with it in that orientation. Bear in mind here that I had the *30 mechanical advance with both plates. I initially thought that changing the springs and weights would solve the problem (I only changed the center plate becasue it came in the kit).

SOOoooo...I dont know. Very strange.

One would think that the old motor was detonating continuously with that setting, but apparently not. (Not like you could ever hear it over the sidepipes) Then again, I couldn't tell you what the initial timing was back then either. It looks incredibly good except for the broken piston. Also strange that not having the power valve boost referenced didn't cause problems either, but...who knows.

I just shot some pix, Ill try to upload tomorrow. I think that putting a screw in it like the photo in the link that Yellow72 put up might work well. In the meantime I just had an idea and pulled one of the weights and am going to take it to my lab class tomorrow and compare mass of the old and new weights.

 

Some aftermarket are symmetrical and the weights usually lighter and require lighter springs and only affects the rate of the advance. Downside is light springs fatigue easily and are not as consistant as heavier.

It doesn't matter that they don't retract fully, just a way to lessen the advance total.

Look for Gm 375 center and 41 weights used or get a couple of extra GM centers and a good tig welder and a good file.

 

Plugs 3, 5, 7. Yes the center electrode of 3 is quite shiny, that makes me wonder. Light black carbon on them everywhere else, where you see it missing is me having accidently wiped it off.








This is with a screw/nut placed in the arm (more pics later) to limit mech advance and running at about 12 initial and 38 total. I know this is a bit much total, but it seems that if I back the initial down at all, the pipes start getting hot again, which is realy starting to get on my nerves. Actually they are still getting hot at this setting. A bigger screw to limit the mechanical more is too much and only gives me about 12 mechanical and so Ill have to grind down a screw head to get the exact amount, so I can go to 16 initial but I'd kind of like to know if I am getting anywhere first. Is the 16 initial that critical for me? The pipes did seem to be cooler there, but I will have to work on the screw grinding thing to be able to get that and 36 total.

Sigh, Id like to drive this car.

Any fresh ideas, given the plugs?