Lotus Elan and Lotus Elan Plus 2 Forums

I'm rebuilding a spare 3.77 diff and purchased parts from Paul Matty. The only gasket available was the "thick" gasket so I purchased it. It is approximately .030" thick. The manual talks about a dowel type differential and mentions the gasket should initially be .009"-.011". What is the correct procedure for determining the thickness of gasket required?
Thanks
Chris

Just had my diff rebuilt by PJS Sportscars. Paul told me they used a 'thick' gasket. Apparently it?s more to do with keeping it oil tight.

Hi,
Just my opinion but surely the gasket has to be the correct thickness for the output shafts to align correctly.

Regards
Steve

The gasket thickness is a lot less of a miss alignment for the output shafts than the suspension traveling up and down. The gasket thickness only moves the third member, with the output shafts, forward by the thickness difference between gaskets. I'll bet the rubber mounts for the diff allow more front to back displacement than that. Or am I looking at that wrong?

Why, yes, I was looking at it wrong or perhaps I should have gone and had an actual look before typing. Thanks, Rohan, for sorting that for me. Makes perfect sense.

The issue is around misalignment of the actual diff output shaft not the total drive shaft to the wheels. It is crtiical that the centreline of the bearing carried in the alloy back housing lines up with the centreline of the diff carrier bearings mounted on the front diff nose as the output shaft is carried by these two bearings

I was not aware that there we two different gasket thicknesses or how tell which you should use. Perhapa Promotor knows more details

cheers
Rohan

Fords only ever used a thin gasket. The thin gasket is fine in a Ford which uses a rigid steel axle housing. The flange of the alloy Lotus housing is likely less rigid and therefore more susceptible to oil leakage particularly if the fasteners have been over torqued in the past. The thicker gasket probably helps circumvent this.

The question is was the Lotus alloy housing dimensioned to use the thin or thick gasket or were there version for either /

cheers
Rohan

All of the complete Lotus final drives I have overhauled have had the same colour/material thick fibre gasket fitted when I have split the diff nose from the aluminium casing. I have never seen any other gasket fitted. This refers to both early and late type aluminium carriers ie small and large mounting ears.

Whenever I rebuild a complete final drive I always use a thick gasket. They are approx 0.030" thick when new. The paper gaskets as fitted to standard Ford road cars are approx 0.010" thick when new.

My Elan workshop manual - which is a later one and covers up to S4 Elans doesn't make any mention of gasket thickness in the "final drive" section.