Hey guys,
I have a 55 fairlane, 272 auto, with the 58 and newer distributor. I just replaced the centrifugal advance springs on it with the Mr. Gasket 925d springs, as I read that these springs were best for these distributors. After putting them on, they seem very stretched out, and it's is pretty hard to move the advance with my hands all the way to full advance. After reassembling the distributor and starting the car, I drove it and it seems like the car has no guts. It just doesn't have the power it used to have. Are these the wrong springs? Or should I try messing with a timing light and see if the advance is off? Should I just buy a reman distributor? Thanks!

Unless it has been upgraded, a '55 will have the loadomatic distributor.  As those springs are usually used for '57 up distributors, I have no idea how they will affect the load-o-matic.

If a newer distributor is installed, with mechanical advance, one "post" that the springs attach to should be bendable to adjust tension.  Try bending the tab.  And yes, use a timing light to see how the curve has changed.  It's not a good idea to modify the advance curve blindly.

If the distributor is old or history unknown, a remanufactured distributor is also a good idea.



Lawrenceville, GA

The advance springs for the 1957-1959 ball bearing advance plate distributors are different from the later model pivot plate distributors.  The Mr. Gasket 925D spring kit is listed specifically for the 1965 and up distributors so I suspect that’s where your problem is.  If you haven't already checked the timing with a timing light, then that's a good place to start.

Lorena, Texas (South of Waco)

I don't have the loadomatic, and it's also not the ball bearing type. The weights inside look like fat commas. I was reading that the 925d springs are the best for the y block distributors, but they don't seem right to me. I'll check the timing today

If you have one of those older tune up boxes with a tachometer this a great place to use it. When you are reving the engine checking when the timing when moves you can the rpm as it comes in andwhen it's all in. Usually theses kits allow you to get all the advance in between 2500-3000 rpm... Good luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

You may have to put a picture up so we can see.  I have had no problems, they worked good for me along with electronic ignition..



"Came too close to dying to stop living now!"

you have not sead what carb you ar useing,as the 55 carb will send the wrong signal to later dist

To be sure what we are dealing with - does the flyweight part of the mechanical advance look like this?


The modification that changes the advance curve involves changing the stiffer of these springs (lower one in the photo above) for one of the lighter ones in the Mr Gasket spring set.
The upper rotor shaft that fits above it has slots to control total travel of the weights - you are trying to control total advance (by slot length) and speed of actuation - by stiffness of the springs.

This sketch shows one modified to provide 26º of advance at the crank (which is 13º at the distributor.) When used with an initial setting of 10º - set at idle with your timing light - and NO vacuum on the vacuum advance pot - this would provide a total of 36º when the flyweights have "maxed out" in the slots. That's about all you would want with a basic factory motor.

As pointed out above, this only addresses the mechanical advance - the vacuum pot requires a carb signal - different subject. This mechanical curve operates when the engine has a lot of throttle and vacuum is low.




 
 Steve Metzger       Tucson, Arizona