Distributor Springs

[russnj]

Should the two springs on the weights be the same?

On mine the one at the top of the picture is lighter and is tight, the lower one is heavier and is loose.

[rickf]

Can't answer your question but that think looks NASTY!

[russnj]

Yeah, I think this is why mine does not run good at speed. It idles ok but I have to put the distributor all the way to the firewall to get to the timing mark and then is does not run well. I am running it with timing mark about 1/2 inch advanced from 6 degrees. I hope someone knows about the springs.

[Fil Bonica]

Go look at the parts book to see if they are the same
Spend some time and douche that thing!

Just some thoughts.

Fil Bonica

[rickf]

It is pretty much normal to have two different springs in distributors.

[JeepMagician]

It is my understanding they should be the same. The mechanical Advance is designed to operate on a fine curve as engine rpms builds up to advance the spark but keep it from knocking. (piston speed increases but flame front does not) At idle there should be little to no mechanical advance. (except in some engines that have Manifold ported Vac advance but these engine do not have this) These springs can be bought and have different rates to adjust the curve of advance to rpm ratio. (oddly enough called Re-Cruving a Dist.) I helped to a couple on some old corvettes. Lot's of trail and error.

I suggest cleaning the Dizzy and replacing BOTH springs and go from there. The loose spring could be allowing your advance to come in early at low rpms.

[rickf]

You will find the tight spring is a lighter pull than the loose spring which will have a higher rate. As the rpms come up and the centrifugal force increases you need stronger spring force to slow down the weights. Hence you start with one light spring and as that one get out to about halfway the other, heavier spring starts to add more resistance to the mix and it all evens out. Different advance curves will call for different springs and rates. I just reset the curve on my big block motorhome and went through 5 different combinations before I got what I wanted. And by the way, you want the advance to start coming in early.

[Surveyor]

Just a random pic off the net. Looks like two different sizes to me and matches yours with the thicker spring towards front of engine.

[JeepMagician]

You will find the tight spring is a lighter pull than the loose spring which will have a higher rate. As the rpms come up and the centrifugal force increases you need stronger spring force to slow down the weights. Hence you start with one light spring and as that one get out to about halfway the other, heavier spring starts to add more resistance to the mix and it all evens out. Different advance curves will call for different springs and rates. I just reset the curve on my big block motorhome and went through 5 different combinations before I got what I wanted. And by the way, you want the advance to start coming in early.

By early I was meaning at idle rpms.. I know manifold ported vac advance had advance at idle then they switched to carb ported advance when emissions started getting more tight. Total guess as to what his issue was or could be. I barely remember seeing stuff with two different springs but the few I watched be done had same springs so that's all I had to go off of. Of course those were 65 and 71 Corvettes not a M151!

I could always see at work if one of the spare Dizzy's show the same thing now I think about it. I'm sure we got few laying around.

[Fil Bonica]

The springs carry two different p/ns
7059536 and7059537.
What the difference is ?
Who knows!!

Fil Bonica

[dr. trinkmann]

Sorry guys to come up with tihs again, but my problem is:

When I inspected and partially disassembled my distributor for cleaning, the outer 'ear' of the stronger spring broke loose because of heavy wear.
Ok...having no suitable spares in my stock I spinned off a little bit wire from the broken spring and bended a new 'ear' on it.
But now this spring is shortened a bit and not the spring with it's original properties anymore and has to be replaced soon.
Unfortunatelly here in germany theese springs seem to be pretty bad to get.
My preferred parts-dealer only has one kind in stock, but can't tell me wether it is the weaker or the stronger one.
Referring to the TM's I also can't assign wich number matches the weaker and wich the stronger spring.


The numbers of the spring in stock of my parts-dealer name as follows:


Part-Number: 7059537

NSN: 5360-00-168-7164


Wich one is this (hope it's the stronger one)?
Please can someone help me out?

Thx
Dr. T.

[rickf]

Looking at the 34-p manual figure 45 it is impossible to tell which spring is which. If you get the NSN numbers for both springs and Google those numbers sometimes you can get physical information on them from the myriad of websites that come up. It is going to be a tough search but that is all I have to offer at this point. I do have some old distributors laying around I could salvage a spring from but right now I am dealing with moving all of my dads estate stuff around and trying to get things in order.

[m3a1]

Wow, that picture of your distributor housing looks like a coil melted down in there. Anyway, let me know if you get really jammed up with replacing this spring. San Antonio has a business called Alamo Spring Company. It's an amazing place. If push comes to shove, I'm half betting I can pull a spring off my spare distributor housing, take it down, and have em match it for you.

Cheers,
TJ

[dr. trinkmann]

Ughhh...didn't suggest that even the cracks, like Rickf, can't assign that NSN to the corresponding spring.
Think I will order the available spring and see what I get.
There's at least a 50:50 Chance to get the right one

Thank you gents
Dr. T.

[Vzike]

I somehow posted the following in the wrong thread. .....


I just went through six distributers.

All had two different size springs, so I'm going with the assumption (yes... I know how assume is spelled), that they came with two size springs for a reason.

I ended up with three good distributers, and a set of swiss controls with rotor and coin, so it was worth the day I spent on it.

I tossed all the Prestolite controls, since the potting mix was melted and oozing out. I tossed one complete distributer that that was rusted out, and one is on the shelf because no matter what I do, the rotor hits the swiss control. Very weird.