Lotus Elan and Lotus Elan Plus 2 Forums

I am in the process of installing a Burton cassette setup. When I went to trial fit the half moon sump gasket , I found that it would not fit due to the gap being too narrow. Has anyone else run into this? I have a number of half moons, cork, rubber and plastic, none of them are quite right.

Below is a comparison of a stock front cover vs the Burton.

Anything is possible with those Burton covers. From the picture it looks to be a very rough casting in that area. If it’s not the same width as the original cover it is wrong and question then becomes how wrong. What do they measure - original versus Burton’s?

The stock cover gap is 7mm, Burton 5 mm.

It it were me I’d go back to Burton’s and complain. If you do I’d be interested in hearing what their response is.

Well I hate to spoil the party with data but here goes

The front cover seal groove was 5.5 mm originally and is the same on all the modern replacements I have bought both from Burtons and others . It looks like your original cover has been machined to widen the groove for some reason ... probably because they had a seal set that did not fit.

The rear seal carrier groove was 7.0 mm in the orginal Ford implementation of the cork sealing version rear lip seal carrier and 9.7mm on the later rubber seal implementation. Lotus stayed with the 7.0 mm version through out the engine production.

There are many issues that have been previously discussed of the cork seals not fitting due to these differences and the seal kit suppliers not understanding the differences.

Yes the Burtons casting you have looks like crap also in the seal area and i would be worried about porosity in the casting especially around the coolant containing areas

cheers
Rohan

rgh0 wrote:Well I hate to spoil the party with data but here goes

The front cover seal groove was 5.5 mm originally and is the same on all the modern replacements I have bought both from Burtons and others . It looks like your original cover has been machined to widen the groove for some reason ... probably because they had a seal set that did not fit.

Only correct if there wasn't an unknown design change implemented during the production run - nothing surprises me with these engines. That groove in the cover pictured actually looks quite original but without seeing in in the flesh it's difficult to know. The other possibility is that the cover that seems to be original Lotus is not in fact original Lotus.

Anything is possible with Lotus manufacturing consistency .....but I have a range of spare front covers both orginal from early and late engines and some new replacement covers and they are all 5.5 mm.

I have just checked a Lotus cover and a Burton version - both measure at 5.5mm.

Mike

I found my original Lotus front cover today during a clean up. The seal groove measures 6.3mm for most of it's circumference however for the last 15mm or so at each end it measures 7.0mm. There's actually obvious machining of the groove that has occurred over this 15mm length to take it out to 7.0mm. Original cover and 1970 Escort Twin Cam application with the big wing sump. Something must have happened during production if earlier ones are 5.5mm or it might have something to do with the type of sump fitted - big wing or Cortina.

My brand new, yet to be fitted standard front cover groove is 7mm at the top, narrowing to a very tight 6mm at the groove base. The matching cork is 6mm wide...

I just checked three original timing cases and non are what could be described as “precision machining” with them varying from 5+ mm to 6+ mm but non were 7mm.

I don’t think mine was machined, I looks like an as cast finish!

Richard Hawkins

Yes I think you are right, probably why there is such a variation in all the cases. Colins way of keeping the costs down