[doc] Re: "Shock update!!!"

["Walter Coe" <Whalt@xxxx>]

Paul,

A few caveats when using these shocks on the rear:

Firstly the shock's intended application does not have the lower eyelet bushing holding the weight of the car. Thus when the suspension is at rest, the forces on the bushing are mostly neutral. But when used on a DeLorean, most of the car's weight rests on this bushing compressing one side of it considerably. Over time and with use, this may elongate the bushing effectively giving the suspension no dampening for the first few millimeters of travel. This puts a harsh edge on every bump before the shocks can start to dampen.

To fix this problem, Marty is replacing the soft eyelet bushings with a harder material. If you have access to a lathe then maybe you can cut something down from an off-the-shelf plastic bushing.

Secondly, the Lotus suspension design puts a lot of lateral forces on the top of the shock. This tends to cause the shock's top shank to push through and divide the upper & lower halves of the bushing. Once through then it clunks & wears on the frame. According to Rob Grady, this is a problem even with OEM shocks. The solution is probably to make a new bushing out of a harder material.

Third, on these after market shocks, the lower body was not made to have a collar/clamp installed. I would like to see what one of these shocks look like internally to see if any compression of the body would affect internal clearances. And then consider how well the steel eyelet is welded to the body. Is this weld strong enough to hold the car's weight?

Remember that Jim Witherspoon who came up with the Grainger collar clamp idea suggested machining one side to fit into and stabilize the spring cone. Without that the cone may shift. 

I would prefer to see someone come up with a design that keeps a neutral weight on the lower shock body. Byrne Henninger did this but his design has issues, too. It's basically a tube with a flange on top to hold the spring cone and holes through the bottom lining up with the shock eyelet. The bolt that holds the lower part of the shock is already in single shear. It appears to me that Byrne's tube puts this force even further from the hub carrier making it worse. Then there are issues with bushings, bolt wear, etc etc. John Hervey was going to offer this kit through his SpecialtyAuto site but his liability insurance wouldn't allow it.

Walt

[Non-text portions of this message have been removed]