Category Archives: RSm GTv6 #79

News for the #79 V6 racing MR2.

Problem: 1991 Toyota MR2 Clutch Releasing Too Close To The Floor

Problem:
ACT Performance Clutch releasing very close to the 1991 Toyota MR2 floor.

clutch

I did some more research in 2015 after Troy Trugleo raced my car. He complained a lot. We had just grown used to the pedal release point. I was at a loss as to what to do.

I searched the internet for a few days, weeks… and then months.

I found a thread on a Honda forum that discussed this same issue. The OP was using a ACT racing clutch and the release point was on the floor. It was discovered that the ACT pressure plates are made by Exedy. They also make a few other “performance clutch pressure plates”. The Exedy made pressure plates have a shorter height as compared to the OE Honda pressure plate. The height is only by a millimeter or so. The fix was to put a washer under the release fork pivot stud.

62217_fig_8_1

I was then speaking with Gouky who had said he was having a hard time keeping E153s working in his V6 race car, and he mentioned another endurance race team was having the same issues.
I mentioned my finding on the Honda forum. He suggested trying to fit a body panel spacer U-washer in through the access hole. I tried doing it on a E153 that was out of the car and to me and my fat fingers there was just not enough room.

So two weeks ago at Watkins Glen we lost a transaxle when the front engine mount bolts broke and shoved the transaxle into the frame rail. Here was my chance to test the theory.

broke

I used a regular off the shelf washer. It was between 1 and 2 mm thick. Well used but clean. No clue where it came from. I unscrewed the pivot stud under the shift fork, and put the washer on the stud and torqued it back into place.
Done

After reinstallation of the new transaxle we tested it.

Release is now where OE release is, in the middle of the clutch pedal arc. Shifting is much more precise as the gear shafts have more time to slow when you shift gears, thus slowing the wear on the sychros.

BRD_shift_bushings
Now I am working on a fix for the wearing of the nylon bushing that is on the number 2 shift fork. I think that by using the solid shift cable bearings/brass bushings, that too much pressure from the shift input is being applied to the nylon bushing to the shift hub that causes abnormal wear.
The fix would be to use BRD Polyoxymethylene bushings at the end of the transaxle side of the shift cables. I think this will allow a 30% less force to the nylon, while still allowing for an accurate shift feel. More on this after we test it at Charlotte over the 4th of July weekend

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Testing the new Zipline Alignment Stands

Zipline Alignment Stand

I was speaking to our sponsor and driver Gene Bird about some stands for the race car that would allow us to easily do alignments in the shop or at the track. It needs to be safe and easy to use. Then it was mentioned that having something that would also allow us to easily set ride height and corner balance the race car would make life really easy. I made a plan up and Gene made a few suggestions and then set off to his mad laboratory at Bird Manufacturing.

Soon he presented this sweet stand to us at the VIR ChumpCar 12-Hour enduro. We did a quick test and it worked well. We then tried it out a couple of weeks ago on Mike Helm’s EP MK1 MR2 at the SCCA Majors Tour when they visited VIR. It worked great on his 4×100 lug pattern as it did on my 5×114.3 of my MK2 MR2.  The design idea was that it should work with all versions of the Toyota MR2.

The design allows the camber, toe and caster to easily be set. There is no need for slip plates as the stand is on heavy duty casters that allow it to twist and turn as you adjust the setting of the toe. The camber is set as the stand has built in tilt.

Simple installation. Jack the chassis up. Remove the wheels. Attach all four stands to the wheel hub, torquing the lug nuts in place. Put the plate under the stand, and slowly drop the car onto the plate, adjusting the plate as the suspension compresses. Let the car settle for a few minutes. I pushed down on the chassis to test how stable the system is. and it is just like the chassis sitting on jack stands.

The simple design allows the use of either high dollar camber /caster gauges or something as simple as you iPhone or Android with a angle finder app.

zipline2

I am going to make a set of aluminum plates with adjustable feet that this can sit on to allow us to make a level platform to do alignments on. This will also allow us to get the correct rake as we use larger diameter tires in the rear, which are taller than the fronts.

We will also be able to put the scales on the platforms, with the stands on top of the scales. We can then corner weight the car when we start using coil over dampers.  Having easy access to the springs and suspension will make alignments a breeze, either at the shop, or at the track.

For more info contact Gene at:
Bird Manufacturing & Design
51 Station Street
Johnstown, PA 15905
(814) 288-6464

Drive shaft repair

We had problems with the right rear drive shaft on the number 79 MR2 at the vir 12 hour race . So yesterday I started tearing down the axle and found that the intermediate shaft bearing was on its way out. So a new one was ordered.

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Inner CV inner race worn and damaged

The inner cv was torn down first and I discovered that the inner race was severely damaged. The cage had just a little bit of wear. So the inner race and cage were replaced.

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Crack in outer CV cage.

I next tackled the outer CV. As seen above the cage was cracked. This is a failure that would spon end a race prematurely.

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On the left is a MR2 turbo outer splined drive unit and thr right one is from a 94 Camry. I used this eith a new cage and a good used inner race.

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Assembled outer CV.

I need to find a supplier for the MR2 inner races. The Camry CV works, but the ones i have use a different spline count, so you end up reusing the worn inner race on the MR2 shaft.