I need help recurving a distributor

[cbosman1]

Thanks to the help in another post I found that my hesitation problem was not my carb, but instead it's my distributor not advancing enough mechanically. It is on a 1953 Plymouth Belvedere. I already have the pertronix ignition installed but even with my springs completely loose I still only get half the advance that I am supposed to according to the book. Right now it starts advancing at 800 rpm (1 degree) and maxes out at 10 degrees at 2,200 rpm. The hesitation is gone, but if I can get more mechanical advance it should give me more take-off power. I did already take the distributor apart and lubed the weights so they move nicely.

Does anyone make springs for these distributors?

Is it a good idea to put looser springs in there I found at a hardware store?

Can I somehow make the stock springs work better?

Any help here is greatly appreciated!

Chuck

[greg g]

is your vacuum advance working properly???

[cbosman1]

Yes, it is working pretty good. The vacuum diaphram is good. It wasn't starting soon enough so I took out a couple small shims and now it starts at the correct vacuum. At it's max the vacuum advance is still about 4 degrees short of what the specs call for though. I figured this was probably OK. It is the mechanical advance that is way off.

[cbosman1]

So here is the information that I gathered on the distributor advance:

Total Mechanical and Vacuum advance is now 26 degrees @ 2,800rpm

Vacuum only advance is:

1 degree @ 5psi

3 degrees @ 6psi

10 degrees @ 10psi

14 degrees @ 14psi max (the max should be 19 degrees @ 16psi)

Mechanical only advance is:

0 degrees @ 700 RPM

0 degrees @ 740 RPM

1 degree @ 800 RPM

2 degrees @ 1,00 RPM

3 degrees @ 1,200 RPM

8 degrees @ 2,050 RPM

10 degrees @ 2,260 RPM

Mechanical only advance is supposed to be:

0degrees @ 700 RPM

2 degrees @ 740 RPM

10 degrees @ 1,200 RPM

18 degrees @ 2,050 RPM

20 degrees @ 2,260 RPM

Any ideas?????

Chuck

[Jim Yergin]

Chuck,

Is it possible that somewhere along the line a different distributior was installed in your 1953 motor and that distributor has different specs?

Jim Yergin

[cbosman1]

Good suggestion. The part number on it is 1AT-4101 which should be the right distributor. The problem is that when we first got the car the timing was all over the place at idle it would jump as much as 4 degrees either way. At that time I looked in the distributor and saw that both springs were completely loose, so I tightened them up so the distributor would return at idle. Now I'm trying to get them loose again. (but not to loose.) I should probably just start over with a set of original springs. Anyone have any springs laying around?

Chuck

[Don Coatney]

How did you "tighten" the springs?

When you say your vacuum advance starts at "1 degree @ 5psi" are you using compressed air to check it? Vacuum is measured in inches of mercury.

Where in central California are you located. There may be other forum members in your area who can help you out with springs.

[moparalltheway]

Just change the springs and weights.

[cbosman1]

To tighten the springs I took one loop off of each. It was enough to take the slack out of the springs. Now I'm finding that some slack was probably supposed to be in there.

I checked the vacuum with my vacuum gauge, so I made a mistake on using psi.

I would like to start with another set of original springs, does anyone have some or know where I can find them? I'm located new Fresno California, if anyone in the area has any extra springs they are willing to part with.

Thanks for the help.

Chuck

[greg g]

Distributors are pretty easy to score at swaps and on ebay. Over the years i have aquired several, You might just want to grab one and try it in your car to see if it makes a difference. I found a shop that still had an old sun distributor machine and a guy who knew how to use it. I took in 4 dists and selected the one that most correctly spec'd out. So my 56 Plymouth engne has a 54 truck distribtor. The curves are slightly different, but within one or two degrees.

check your personal message.

[James_Douglas]

Chuck,

I am in San Francisco and I have a distributor machine.

Also, keep in mind that our modern fuel additives make the gas burn "faster" for a more complete burn. Since the flame front moves faster, the advance curve needs to reflect this. Using the original curve is a good starting point, but several people I have discussed this with think that the intermediate part of the curve could use a little more advance than the stock curve.

Best, James

[Don Coatney]

I'm located new Fresno California, if anyone in the area has any extra springs they are willing to part with.

Thanks for the help.

Chuck

There are at least two forum members in Fresno. Mark Haymond who lives in the north end and Bob Riding who lives in Clovis. Also Turners junk yard in Fresno is rumored to have several old mopars.

I lived in Madera Ranchos for several years before moving to Tennessee.

[moparalltheway]

Just put a magneto in it!

[cbosman1]

Thanks, I was thinking of buying one off of ebay anyway, so that's probably what I'll do next. I also saw that Langdon has a HEI version for the old mopars for $185. Has anyone bought it and does the curve match up to these old engines?

[steveplym]

Thanks, I was thinking of buying one off of ebay anyway, so that's probably what I'll do next. I also saw that Langdon has a HEI version for the old mopars for $185. Has anyone bought it and does the curve match up to these old engines?

I'm pretty sure that blueskies has the Langdon HEI in his car. He might chime in here or send him a PM.

[Mark Haymond]

I live in North Fresno and have a spare distributor that we could use for troubleshooting. I'll try sending you a private email.