Lotus Elan

Trunnion troubles

PostPost by: handi_andi » Wed Aug 12, 2009 9:35 am

Single Bolt is no different from the existing trunion to lower wishbone arrangement surely? They just appear to have extended casting out over the tops of the lower wishbone where the existing one is just flush. Have to admit to being very sat on the fence about it, the existing arrangement has been proven over allot of cars doing allot of mileage, where as this has only been in service for 5 years on a limited number of cars. What is interesting as well is that they are talking about making service items available after 5 years, where as most Spitfires and the like will still have the original uprights and may only be on their 2nd or 3rd set of brass trunions after 30 years. There is nothing per sei wrong with the existing design and it is designed to preferentially wear as long as it is maintained. I do like the simplicity of the new design though, just like allot of people have problems squaring the circle

Cheers

Andy
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PostPost by: davidj » Wed Aug 12, 2009 11:26 am

Sorry I did not explain myself very well. The existing design pivots on the centre line of the bolt, while, I guess, this new design pivots on the ball joint with the housing bolted solid on the wishbones with the single bolt. I don't think it would pivot on the bolt. There will be a very high turning moment in this area which could result in all kinds of problems if the housing is not secure. An improvement would be to increase the size of the housing and use the damper mounting as well, but that would result in complications with the bottom mounting of the damper.

Although it is a very good idea, I have lost my bottle and ordered two new GT6 uprights.

Cheers,

David
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PostPost by: handi_andi » Wed Aug 12, 2009 11:34 am

David

Good point, there is an eccentricity and hence bending moment set up by the pivot point being further outboard than with the original trunion. I wonder what else it could over stress in the process and how it affects the suspension geometry

Andrew
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PostPost by: davidj » Wed Aug 12, 2009 8:09 pm

Hi,

One last question; I presume the stub axle just presses out? Any tips?

Cheers

David
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PostPost by: paddy » Wed Aug 12, 2009 9:32 pm

The stub axles are a taper fit. I've never removed one but I'd go for moderate force + moderate heat and increase both until it comes apart.

Paddy
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PostPost by: bramsaar » Thu Aug 13, 2009 9:05 am

David,
Just go to a Truimph supplier and get the upright and the brass part including the seal.
Make sure that when you buy another one that, when you need to replace lefthand side f.i that you also get an upright and trunnion with lfhd thread or righthand vs. righthand thread.

WHen fitting don't put grease on the threads but fill up the entire trunnion with some gearbox oil. Leave the oil in it and use the seal otherwise sand gets in.

Takes some time to change everything but is worthwile
Cheers
Bert (orange 26r)
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