so so sexy! You wouldnt be willing to do a write up of the install would you? It would be really handy for the other str people thinking about running motons.

 

Unless you want to have a custom nut/shim machined, you will want to purchase top mounts designed for the specific shock due to variations in shaft diameter throughout different manufacturers.

Megan, T1R, and GC top mounts will not work with Moton shocks unless those companies (or the purchaser) can machine a nut/shim to accomodate the ID of the spherical and the OD of the shock shaft.

 

The GC top hats should then work with Penske 8100s. In the photo below you can see the shaft extender that allows use with stock top hats. The diameter (12 mm) is the same as the Koni Sports and the length is 2.5 in to the shoulder. The shock shaft is 0.625 (5/8) in and would likely be where the spring retainer would go.

Anyone use non-stock top hats with Penskes that could show how it's done?

 

Exactly. If you're doing a pillowball upper mount, you need to have the same shock shaft or if your shocks have a smaller OD shaft than the ID of the spherical bearing, then you can just get a simple shim machine to fit. If the OD of the shaft is bigger than the ID of the bearing, then you're SOL.

Now, on the GCs, since it's a polyurethane bushing, if it's not too big of a difference, you can drill out the bushing and make it fit. Now, without knowing if the bushing is a single bushing that is pressed in or a 2 piece design, I wouldn't know how large of a hole you could drill and not have the shaft contact the aluminum or the upper shaft.

In Brian's case, those Motons have FATTY shafts, so he'll most likely have to go with the SoS top mounts for sphericals. IMO, the only real advantage any of these alum upper mounts gives you is the weight savings, and for me, I could use the 480 on something else, but the GCs don't seem like a bad deal.

Speaking of weight, does anyone know how much the stock upper mounts weigh?

James Yom

 

I am leaning towards the SoS ones. I will give Moton a call on Monday and see what they say first though.

I don't see an advantage to using the aluminum GC ones over the stock ones.

BTW, I found 2 sets of stock AP1 wheels in my basement from AS days. Anyone need some? $150 a set. Two sets shown on the left here:
http://www.briangt.com/gallery/wheels/wheels_1?full=1
(all are dirty except for 1 wheel, which was cleaned to see if was possible to get off the brake dust.

Ordering parts today for the diff. It should be a pretty simple swap for the OS Giken, as I will be replacing the ring and pinion gear also, so no bearings to pull off, and will just press new ones on. Looks to be about $350 for all new diff bearings and stuff. Anyone know off hand what size the lock nut for the companion flange? I need to make sure my friend's shop has the right size socket for this, as they mostly do BMW stuff.

EDIT: appears to be 22mm with a recommended 95 ft/lbs of TQ to get it seated right with the new spacer.

-Brian

 

Just happen to have one sitting here. It weighs 1.5 lbs including bushings.

How much do the GCs weigh?

 

When you say "spring retainer," do you mean the upper spring perch? If that's the case, I think the GCs would work. If the base of the adapter is where your spring perch would go, other than trimming the bumpstop to accomdate the spring perch and possibly using a shorter spring if you run out of thread on the body, I don't see why it wouldn't.

You're Penske insides look real purdy

James Yom

 

I just reused my stock upper hats. I removed the metal sleeve from the assembly and then drilled out the two bushings. Then I put the moton upper perch on the shaft to assure a good axial spring relationship and then I slid the stock top hat and bushing down over the shaft. I did the same thing with my CRX. Shoot, I think the top hats for the CRX and the S2000 are the same.

If you're worried about the weight of the stock top hats, swiss cheese them. (yikes)

 

Yes "spring perch" and agree the bump stop would need to be adjusted.

Here's an example of a spring perch that may work.



Those insides (shims as purchased) are all going for a new build.

 

I wish I knew, but I don't own a set... my unedumacated guess would be around half the weight?

Since this is part of the shock/spring that's bolted to the car, I would assume we're shaving off sprung weight of the car vs. unsprung weight?