Installing a Reliable Power Transmission System for the Toyota 1JZ-GTE Engine

═══════════Frequently Asked Question═══════════

Author:BRN22

Decided to write about the clutch, maybe someone will find it useful.
If anyone wants a manual transmission but considers R154 prices unreasonable, you can look here www.drive2.ru/cars/gaz/31…froggy56/journal/2452273/

In general, my problem is such that after the swap I was left with a W-series gearbox, for this only a flywheel (13405-46040) clutch housing also known as
bellhousing(31111-22140), as well as the clutch basket and disk from a Supra JZA80 with W58 gearbox.
All missing parts were bought new except for the flywheel,
the flywheel was lent by a friend who switched back to an automatic, it turned out that they had turned down the flywheel because there were thermal cracks (some drifters or someone else simply overheated it), of course it would have been better not to touch it as turning did not really remove the cracks, and the flywheel still spins without any issues.
Later it turned out that even my friend was scared that it might break and had it turned down again. Consequently, the entire working surface was removed almost to the root which led to clutch slippage.
The clutch lasted for 2 months, then slip appeared on fifth gear, later on fourth, and when the clutch started slipping in third I backed off with the gas pedal)))))
They racked their brains wondering what could cause this but it all boils down to the flywheel as there is no working surface (it was turned down by a machinist), the basket simply doesn't press the disk tightly leading to slip.
I started thinking hard, at first I thought about ordering some reinforced basket or clutch set from eBay, but that's very expensive and not guaranteed to work with this flywheel, so I started analyzing what could be replaced. I looked into 2S, 3S flywheels, S-series flywheels, BMW M30 and M20 one-piece flywheels.

I settled on a BMW e28 engine M30 flywheel (photo of this beast below, it turned out that the BMW clutch is reportedly unkillable and can handle torque, the flywheel sits perfectly with JZ as original, the only issue being the keyway, which I swapped from an automatic JZ flywheel.
The keyway diameter for the BMW flywheel is 261mm while the JZ is 263mm, meaning the keyway on the JZ is 2mm larger in diameter, and here everyone does what they like, some center it and weld it, I went a different route.

Machinists cut (may their gods forgive them))) hardened metal to the keyway diameter with allowance for hot mounting, leaving a very thin line.
Then I heated up the JZ keyway on a torch and mounted it onto the BMW flywheel, it fit perfectly!

The result was the following setup: BMW flywheel+basket, 240mm Toyota clutch disk because the BMW one has an entirely different splined part!