Does anyone know of any difference between UK and US XK8s that would affect coilover installation?

The coilovers I purchased for my 1999 XK8 (USA) do not lower the car. The company I ordered them from has installed them on a UK version XK8 with the same size tires (18") and achieved a 1 to 1.5" drop.

I can only achieve a .5" drop with the coilovers adjusted to their max lowering. (Stock is 15.75" from center hub to center wheelwell. My measurement is 15.25")

We have done extensive measurements - they are assembled correctly - disassembled and reassembled. They are installed correctly.

We removed the coilovers and lowered the car to see if there was any binding or issues - none - the car lowers all the way till it's sitting on the brakes with no suspension in place.

The coilovers should offer up to 60mm drop (2.3" which would render the car undriveable) but can only achieve a 19mm (.75") drop with the coilovers as low as they will go (i.e. no threads showing and collar turning by hand)

The strange thing is that they say they fitted them on the same model UK version of an XK8 with the same tire size and achieved lowering, with plenty of threads to spare to lower more.

Mine is stuck at .5"

There has to be some kind of difference in the UK and US version? What else could possibly explain this?

Also - the tank is full of fuel - so that's the max drop that would ever occur, as fuel burns and weight decreases the rear would raise back up.

Can anyone think of anything? Anything at all? Completely stumped here.

 

Have they sent you to correct spring rating / Spring length ? Check back with supplier on wire diameter/ number of coils and length.
The car is the same weight .as UK

 

Springs are the same, length and rating. Same coils and length.

Supplier was able to get 6.5" measured from bottom of rear sill jacking point to the ground. But with 13 threads visible on the coilover adjustment collar.

I am now showing 6.5" measured from bottom of rear sill jacking point to the ground. But with only 4 threads visible measured from bottom of coilover collar.

That's a really big difference especially since at 4 threads the unladened spring when the car is raised is very loose. 13 threads would make it very tight.

 

They have to have sent you the wrong springs. Have you asked the supplier if they can explain what you're experiencing?