View Full Version : TR6 1974 TR6 distributor advance spring specs

04-08-2012, 09:53 PM
My distributor was taken apart and the springs were mixed in with springs from other Lucas distributors. Would anyone know the wire diameter, outside diameter, number of turns, and overall length information so I can find the ones that were there originally. Rough measurements might be fine cause there's only 10 springs to sort from.


04-09-2012, 12:16 PM
Greg you might be better off sending the unit off to Advanced distributors, he rebuilt mine and it works great, before the weights were frozen. he also puts a new bushing in and checks the whole thing, and will recurve it

if you didnt take the springs off how will you even begin to get the right ones back on


04-09-2012, 05:11 PM
By the way, I'm the one who mixed the springs together. My bad.

Spring forces are governed primarily by material properties (alloy and temper) and winding dimensions. If we ignore the material aspects, for the purposes of sorting, then the winding dimension specs should be fine to get me in the ballpark. I know there are plenty of opportunities for tweaking things, but I'm just looking for the basic spring setup, so I can hav a starting point.


04-09-2012, 07:33 PM
You will need someone with a distributor taken apart. Otherwise the stretched spring measurement would be meaningless.

Geo Hahn
04-09-2012, 09:15 PM
I would expect one spring (thin wire) to be very close to its relaxed length with the weights at rest and the other spring (thick wire) to be slack (i.e at its relaxed length) with the weights at rest. So measurements & descriptions in situ should get you pretty close.

In fact, a good digital photo may be enough to go on.

Frozen weights are easily fixed... once the distributor is out there is really only one screw (under the rotor) holding things together.

I have never understood how someone can properly recurve a distributor without matching the curve to the engine (other than just installing the stock springs).

04-10-2012, 05:45 AM
Geo, you are correct, there is a lot more information needed to recurve a distributor properly, I didnt see the need to list all that informtion, if Gregg was planning to send it off to Advanced Dist, or someone else they would have asked him for more details

04-10-2012, 02:12 PM
I have a number of reasons why I don't want to send my distro away to be setup right now. Just want a close to stock setup to get the car running.

I like the approach mentioned of judging the primary spring by a slight tension at rest and ensuring the secondary spring is selected to allow delay before it's put under tension.

Since the spring mixup was between distros for 4 cylinder BMC A series cars and the TR-6 distro I'm hoping they designed the at rest length entirely differently and the resorting will then be simple.

Thanks, for the great suggestions.