Leaderboard

Yes. Jon is correct. The bore in the housing has gotten deformed and the bearing is no longer a press fit. The car has 400 lb/in rear springs and no rear sway bar. In the front, I have been running 500 lb/in springs with a 20 mm sway bar, but I recently changed to 425 lb/in springs with a 25 mm sway bar. I'm running 15x10 wheels with Avon 23.5x10.5-15 bias ply slick on all four corners The old set-up worked well for autocross, and the new set-up works for road courses. I will probably just stick with the Konis. I may step up to the 8611-1259 instead of the 8610-1437. Anyone have experience with those?

What Dan is describing is a known issue with Zs that are raced. The forces on the stub axle stretch out the bearing pocket in the strut housing. Had a guy on FB DM me about the same thing just a couple days ago. Now that has me thinking about putting a reinforcement ring around where the bearing is located. I bet that would be pretty easy to do, too...

One avenue I thought seemed promising but haven't pursued is to use the adapters that people sell to screw in a cheap Chinese coilover (AZC, T3, Apex) and find a really high quality strut that fits, like a Penske or Ohlins or something. I think this is essentially the route the Coffey went to get those 46mm Bilsteins in that rally car that went across Asia, but John had the adapters machined because he was way ahead of the curve on that idea, IIRC. FWIW, that guy ended up swapping those Bilsteins out for something he thought was better. Bilsteins are supposed to be pretty tunable, but you have to have someone who can do it, which is a whole nuther can of worms... I think the easy button is to fork out big bucks for the KW or similar high quality stuff.

Might check with Carl Beck at Classic Z cars. Scroll down to Carl's post. https://www.classiczcars.com/forums/topic/44384-sumitomo-mk63-caliper-question/

He's actually a member here. @jdmjunkies.ch