Tag Archives: ACT

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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