Lotus Elan and Lotus Elan Plus 2 Forums

Has anyone toyed with the idea of making an alloy spacer to go between the mounting fixtures of the rear bearing housing and replacing the two bolts with one long bolt? Should add rigidity and strength.

..and weight..

John

Let's see . . . . . .

3" of alloy tube - 2 ounces?

replace two bolts with one long one - but you don't need two washers and one nut. Let's say that adds 1 ounce.

So, a total addition of 6 ounces.

Or, you could thread the alloy tube on either end and use the standard bolts and safety wire the heads of the bolts. I'd guess that would not add any weight.

Although, I guess safety wire is pretty heavy stuff . . . . .

My main concern would be clearance to the wheel. It's very tight even with the half height head bolt.

Would need to use half height nut and exact length bolt. Then you may still have clearance issues. Then there is the question of if there is enough thread engagement with half height nut for the forces involved.

Also moving to a single point of failure rather than two.

Interesting points. Thanks.

If the clearance issues are that tight then maybe forget the spacer but use button head bolts and thin washers with locknuts on the inside. Might give a bit more clearance.

fattogatto wrote: with one long bolt? Should add rigidity and strength

How much strength will it add?

What makes you think it will add rigidity?
Are your bolts loose? Or is your alloy casting bending?

Easy enough to make up a special nut to overcome that issue. Buy what really is the benefit?

" So, a total addition of 6 ounces. "

Colin will be turning in his grave....

John

I'd like to know of your source for the button head cap screws. They'd need to have un-threaded shanks, something I've seen very seldom on a button head. I'd love something like that that would allow me to mount my American Silverstones.

Roger

A cursory search doesn't turn up anything suitable in that large size. This is not a big deal so if there is nothing readily available I'll use a low profile bolt and be done with it.

Interesting idea, essentially the same way that the lower wishbone and hub carrier are joined on the Series 2 Elite and others such as the Type 18. On the Series 2 Elite the hub carrier casting is continuous across the bottom and a long stud is installed through both ends of the wishbone and the hub carrier, nuts are used on both ends. There is more clearance to the wheel rim on the Elite than open the Elan. Don't ever use a button headed bolt on a highly stressed application, they are very weak in tension. If you section a button head bolt you will see there is very little metal joining the head to the shank. I bet you could use a NAS nut and bolt and have adequate clearance to the wheel rim. These bolts and nuts are very strong and compact having small, 12 point wrenching surfaces. Chapman probably abandoned this design because assembly is a bit fiddly. You need to use shim washers between the hub carrier and wishbone to compensate for manufacturing tolerances in both parts.

MS20007 or NAS147 are options.

There is little longitudinal stress in those bolts, it is nearly all lateral, so half thread nuts shouldn't be a problem.

If you want to save weight saw off the redundant spacer running close to the disc, it's only used for jacking the car up!