MA61 wishbone IRS

[Crambo]

Back on topic, I've checked a few measurements and believe I can redrill rear mount holes in the chassis rails to move them back 40mm, too easy, leaving the 4 fronts to be removed off the subframe and build 2 back on in the right place, with extra work I could set up 4 front mount points. The Cressida has a total of 4 mount points as does MA61.
The shock & spring towers will have to be rebuilt to one tower between them.

If the original rear track is 1425mm + 25mm max allowed increase then I figure 46mm offset wheels will do it.

[Crambo]

I went back to the wreckers before the MZ21 gets crushed and got these, the shocks are MA70 that were fitted to replace the original airbag struts.

The towers are a lighter construction than the MA61 because the MZ21 has a parcel shelf and bracing behind the back seat for body stiffening, when I cut out the heavier towers, I will add pipe cross bracing between them to compensate for lost stiffening.

[Crambo]

Some progress, removed outer mounts and made jig to accurately space them to A61 bolt locations.

Trim with grinder and Mig into new position.

Subframe welding complete, next is to relocate A61 rear bolt holes 40mm back also doctor front A61mounts to fit the inner pair of mounting bolts. When subframe is test fitted the wishbones, arms and hubs can be fitted to test track, ride height, wheel offset and flare requirements. When I hit the body with the angle grinder to remove the towers this will be the point of no return!!!

[Crambo]

Fully reconditioned my diff today, it was real cheap, only $8.95 a can.

[Crambo]

I cut out stepped metal section beside original mount and welded in a 10mm plate over the lot to provide mount point for second bolt.
Then added a 3mm thick pad as the inner mounts on the subframe, (can't be relocated) just overhang.


These steel additions to the supra mount are also needed to space the subframe away from the body


Note the brake line joiner taking the place of the T that moves to behind the diff. The lines and the caliper hoses meet at the rear subframe mount points.


You can just see the original bolt slot on the edge of the round pad and new bolts and thick washers used. The brake tube is waiting for bracket and hose.

[brett_celicacoupe]

hows the spring towers going?

[Crambo]

The result so far, next the towers have to be removed for the new ones to be fitted.

[rsdeo]

Awesome work! Can't wait to see the finished results.

[mrshin]

I think I have banana envy...

[Supra_Newfie]

Congrats! Very nice job! Two thumbs up for going through with the project!

Grant

[Crambo]

Hi to all the MK2 owners in Canada. This is a pic of the floor where the original subframe mounting bolt is and you can see the second bolt I have fitted.
If you scrape off the body deadener you will find a square pop out cover over where I fitted the additional bolt?

[Crambo]

OK, the easy part is over, now the towers. I drilled out the spot welds on the pressing that the shock mounts to and removed this section.



After this pic I cut out half of the spring seat.


Now I can see where I'm going,


The towers are about level with the windows and just below the seat headrests!!!
Custom coilovers would compact all this, however I will keep the springs high and stay with the MA70 springs and shocks (which have aftermarket support).

[Crambo]

looks like there's been an explosion (or two)


I cut the spring seat into fingers and folded them up to weld them onto new tower walls, I removed the 1mm thick walls from the donor towers to fit 1.6mm walls that will be stronger and welder friendly not forgetting the rear half of the car is going to bounce on these things.



The parts that have to blend into the inner wheel arch and window sills will be fixed with old fashion steel rivets as in a bridge (only smaller) as the metal is very thin or multi layers of thin.
The real strength was in the 2mm spring seat pressing so why use 1.6mm? apart from the fact I don't have any 2mm, the spring seat pressing is basically attached to the chassis rail by less than 180 degrees, the new tower will be attached 360 degrees with a triangulated, pipe tower brace .




You can't have too many jigs, the PITA is getting measures or references when everything is so round or tapered and in all directions!!
Please don't post to enlighten me that it looks out of shape, maybe it is and the car will drive sideways, hmmmm. drifting here I come!

[Stefan]

I'm curious, what's the effect of all this on your rear roll centre, have you calculated it?

[Crambo]

I'm curious too.