missing distributor spring

[Steve]

What is the purpose of the spring at the bottom of the distributor shaft? I recently replaced my distributor with a 123ignition, and I do not recall seeing the spring. In fact, I am quite certain that there never was a spring under the distributor for the 10 years that I have owned the car.

The reason I ask is because the timing has never been steady at idle - it bounces a little, and is difficult to read. Could the missing spring be the cause of slightly rough idle and unsteady timing, or is it normal for the timing to intermittently bounce several degrees at idle?

Thanks in advance for suggestions or help with this.
Steve

[Allenh]

If you are referring to the spring at the coupling on the distributor to the drive gear, it is there to provide tension on that bevel cut gear.  Without it, the loose end play can cause that gear to move slighty up and down on its drive gear when not on under stress or load and in turn cause a variance in the timing.  So yes, having the spring in place will tighten the timing at idle.  WIll it make it bulletproff steady?  Depends on how tight everything else is.  But it will help.

Allen

[Dave Gallon]

For your reference, the spring is part number 127 993 01 01. It has
become bloody expensive. Current MB USA list is $22.50, my price $16.61.
I also have a used spring available at $8.00. With luck, you can probably
pick one up free at a wrecking yard from a 280SE sedan.

[Naj ✝︎]

Steve,

If you are using the 123 distributor, you need a spring twice as long as the original.

Search threads on 123 distributors, especially on by Peter van Es.

naj