New project: 1976 Cosmo RX-5

[djmtsu]

Time for me to measure now! Thanks Gunny!!

[djmtsu]

28 inches.

Of course....

[GySgtFrank]

Originally Posted by djmtsu

28 inches.

Of course....

Whizbang welded a plate on the frame where he needed to mount the front holes on the RX-2. The rear holes would need a plate anyway to get it at the right height for caster. I would think the bigger concern would be whether the tire would fit under the fender correctly. The FC uses a wider track than the FB and high offset wheels, close to that of the GSL SE. I don't know anything about the overall width of the RX-5, but it looks like it would be plenty wide under there. He has a pretty good write up on this swap in his thread, if you haven't seen it and are interested.

It would be a lot of custom fabrication, but the results and parts availability would be one heck of an improvement.

[djmtsu]

Yes, I've seen his write up. I just don't want to stray too far so that modifications are not reversible.

I wish I could get this thing on a lift, to show how different the suspension is on these, both front an rear.

Up front an 'A arm' style lower control arm, but utilize a spindle/strut like a 1st gen. No tension rod BS. Also, the engine crossmember is independent of the suspension all together (front mount like all old schools).

The rear is a 5 link, like a 1st gen, but places the springs on the LCA's, the shocks bolt to the axle. It also uses a panhard bar instead of a watts linkage.

Billy Waits was spitballing ideas to me the other day about the front. He wants to look into using the FC front control arms, but not the subframe. I haven't looked into it yet, and its been a while since I've been under an FC. My main concern with that option, is the steering. I would have to swap the spindles from left to right to resolve the rear steer on the Comso vs front for the FC. Of course, there is a ton of room up front, so a rack could be mounted, and the steering shaft extended, that way the steering is improved, and the FC stuff stays the same.

Now, what I was thinking, and I don't know if this is possible, is this:

-forget about the FC control arms. See if a ball joint can be used with the Cosmo control arms to use the FC spindle. That also keeps the FC strut. Mount the R&P to the top of the frame rails, since the engine crossmember mounts below the rails (this is also the sway mount FYI).

Ugh.

[GySgtFrank]

It sounds like it is pretty similar to the original 110S Cosmo, but with a solid rear axle instead of the independent rear.

A saying comes to mind. "If you want to run with the big dogs...."
For what it sounds like you are wanting from the car major changes are going to be inevitable. Especially if the parts availability is getting so bad even the Australia boys can't get them.

One of the things I was trying for with my project was to use as many readily available "off the shelf" parts as I could. SA parts are getting harder to find and it will only get worse. It sounds like Cosmo parts are another order of magnitude in hard to find. Since you aren't going for original restoration, it frees up your hand to use other stuff.

The problem with finding a ball joint is that the FC uses a through bolt and clamping style of fastener for the ball joint to brake/strut lower rather than the more normal tapered and bolted set up. You would almost have to find a way to use the press fit FC ball joints with your lower A arms.

It might be possible to have a plate machined that would bolt in where your ball joints go (if they're a bolt in style) that would allow press fitting of the FC ball joint. Alternatively you could have some lower A arms made (or make them yourself) that would accept the bolt on portion of the FC ball joint.

The next question becomes whether you have the clearance for the brake rotors and dust shields with them there. Then finding out if the FC struts are the right length to allow adequate suspension movement and whether the caster would be altered with the different strut mounts on the lowers. Not insurmountable problems, but annoying nonetheless.

The rack and pinion would be the best way to go performance and parts wise, but you would be getting into difficult to undo changes to the steering shaft to hook it up and the mount for the rack has to be very solid. It could be done by building a new engine mount cross brace that would accept the rack in the right position I would think. Lots of fiddling to get it right though.

The Fox body Mustang rack that Billy used in his kit for the FBs works well for a custom Mazda application, since the frame rails are the same width between the Mustang and FB. They also have plenty of length in the tie rod arms to shorten them up a bit if needed. That and those parts will probably be relatively cheap and available for the next hundred odd years or so.

[djmtsu]

If oooonly I could weld.....

[djmtsu]

Been collecting parts, disassembling more of the front clip and such.

FC front hubs and brakes acquired. Motor is pulled, and going to Charles' house so we can crack it open and see what's what before I make a call to Atkins.

The Cosmo is supposed to go to a friend for some welding this weekend, and I am going to get a new rear axle assembly........

[djmtsu]

Well, looks like the Cosmo isn't going to DGRR, or anywhere soon. After taking it to a friends shop, and digging deeper into the front end, it needs both front frame rails. From the firewall forward.

He can't build them, and I can't find any. So, until I learn to weld, and then can make my own, this is going to be stuck in a shed somewhere I guess.

Awesome.

[lilring]

Help me throw a motor in the 8 and you can take that to DGRR

[djmtsu]

I have back up cars...

[85rx-7gsl-se]

Rotary powered backup cars? Good idea lol

[djmtsu]

Update:

Engine teardown courtesy of Adler, Charles, Johnny K, and I think I even see Foo.....

http://www.youtube.com/watch?v=EYdtbM9xV8g

[GySgtFrank]

Somebody needs to give me that REPU in the garage.

[djmtsu]

There's actually 3 there...

[GySgtFrank]

Originally Posted by djmtsu

There's actually 3 there...

You're a cruel, cruel man.