Distributor drive shaft end float.

[E600]

I’m currently rebuilding an early 3.8 and find that the end float on the distributor drive shaft is 9.5 thou. It has a new bush and helical gear.

Has anyone come across this problem and if so how did you cure it?

Tia

Edited to add I have checked other thrust washers and whilst there is only one part number listed have found they vary in thickness by, on the small sample I have checked, by as much as 4 thou.

This implies either, they wear with use or the manufacturing tolerances when new varied.

I have ordered a new one from SNG, albeit repro and will report back when measured.

Ps it would be good to know if others have similar experiences or if engines stripped can measure the thrust washers for comparison. My original is 0.118 thou

[E600]

New washer arrived from SNG and it measured 0.119, so only 0.001 thicker than the 60 year old original.

My next course of action is to have 0.004 taken off the distributor drive shaft which should bring it back into spec range.

I will let you know how it goes

[bitsobrits]

Shim washers of various dimensions are readily available from Industrial suppliers. Have you pursued that route? In the U.S., said suppliers often have a minimum package quantity, but the cost of a 5 or 10 pack of shims will likely be less than custom machining.

[E600]

I would be comfortable fitting a thicker thrust washer, but adding a 3 or 4 thou shim to it, less so.

The drive shaft is in engineering currently being machined to length to get back into tolerance range.

Thanks for the tip, I might need shims for my front wheel bearing spacer at a later date and will search these suppliers

[MarekH]

There is a recent thread on J-L about the need for an oversize thrust washer on the crank. One respondent solved his problem (many years ago) by plating copper onto the back of an oversized shim until it was the required thickness. They also commented that purchasing a batch did indeed yield multiple different thicknesses of washers, so one must assume that was by design.

kind regards
Marek

[E600]

Marek, I read the crank end float thread, and admired the ingenuity of the chap to devise the solution, however, for the distributor drive shaft thrust washer I think both surfaces can be subject to wear, unlike the crank washers.

I have the shaft in with an aircraft engineering company who believe they can turn down the 4 or 5 thou required.

Regards
Pat

[E600]

I had the thrust washer shoulder turned down and the end float is now 0.0045 so back to specification.