Lotus Elan

Distorted front cover

PostPost by: tim22 » Mon Jun 12, 2017 10:28 pm

Hello

After stripping down the engine on my +2 have found a problem I would appreciate some advice before proceeding. The surface of the front cover on the side running alongside the timing chain damper is seriously distorted, bowing about 2mm over its length so that the damper pad is proud of the cover at one point. The distortion is offset to some extent by a corresponding bow in the opposite direction on the back plate but the front and back plates do not mate perfectly.

Can the surface of the front and back covers be machined flat without affecting the seal and operation of the water pump? Are there tolerances for re-assembly and for skimming? Is a new cover the only long-term option? I was planning to use Loctite 518 as a gasket, which has a max gap size of 0.3mm, but can't see how the cover can be replaced in this condition without risking oil leaks.

If I do need to replace the front cover, is anybody able to offer a serviceable second hand part for less than the cost of a new replacement ?

Many thanks

Tim
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PostPost by: 2cams70 » Tue Jun 13, 2017 12:58 am

I'd try bending it back using some strategically placed wooden dowl in a press or vice and maybe a little heat to get the worst of it out. The very final flattening can be done by machining.

I've had great success in flattening the mounting flange of a seriously bowed Weber 40 DFAV two barrel downdraught carburettor using this method. Admittedly the carburettor material was zinc/mazak so a little softer than aluminium.
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PostPost by: Lyn7 » Tue Jun 13, 2017 6:36 am

Hi Tim, I've used a warped back plate in the past. This was relying on the bolts to bring it back into shape. I only used the normal gaskets and Wellseal. It didn't leak and more than usual :lol: . Eventually when it was removed for some engine work it was straight!! I presume it warped due to poor storage, maybe something pressing on it.
It came back ,in normal usage though.
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PostPost by: Craven » Tue Jun 13, 2017 10:55 am

I’ve used a metal loaded epoxy ( J B Weld ) to fill screwdriver graunch marks, maybe a flat surface, glass, and cling film or bolt the two together with epoxy on one piece with cling film between.
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PostPost by: billwill » Tue Jun 13, 2017 3:44 pm

If you are going to need to replace the timing case consider getting the modular water-pump set from Burtons.

It is expensive but includes a new back & front plate for the timing case.
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PostPost by: tim22 » Tue Jun 13, 2017 9:45 pm

Thanks guys

Appreciate the advice. I re-fitted the front cover to the block this evening as a dry run and after progressively tightening all the bolts the whole assembly pulled together with a much better fit than I would have expected. The whole thing is so flexible that it doesn't seem to need to be accurate, or at least I'm hoping so.

I should introduce myself ... I bought my 2+2 in 2004 and have used it as my main car for that time. It's often found on a ramp in a friend's workshop near Lingfield. If anybody lives nearby and wants to drop in one evening I'd be very happy to buy you a beer!

All the best

Tim
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PostPost by: richardcox_lotus » Wed Jun 14, 2017 8:23 am

Gets my vote. I'm in Edenbridge so not too far away......
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PostPost by: tim22 » Wed Jun 14, 2017 11:26 am

Thanks Richard .. I've sent you a PM
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