TR6 Tech Forum

Hi there,

According to the inspection report on my 1970 TR6, I may need a new clutch release bearing for my Eaglegate Toyota W58 transmission. From what I've read, the advice is to replace the clutch plate as well.

What is everyone's experience replacing the clutch release bearing on these W58 transmissions? How many shop hours should I expect for an experienced mechanic, and therefore the total cost?

What else besides that one bearing should be replaced?

Thanks in advance for the help.

Fred Christensen
Bend, OR

Fred,
I recently purchased the Eaglegate kit and a W58. The parts you're concerned about here are all Triumph parts. Edit: the disc is Toyota; pressure plate and release bearing are Triumph.

All your questions can be answered by the Bentley manual and the various clutch-related articles on Buckeye Triumphs. The latter are saying it's an 8-hour job to R&R the trans. A lot of the work has to do with removing parts of the car interior, such as the dashboard support.

BPNW sells "Gunst-type" release bearings and other clutch parts.



Edited 1 time(s). Last edit at 2022-01-17 12:19 PM by steveg2.

Hi Steve ... OK thank you for that? I'm assuming this is the right clutch kit: https://www.bpnorthwest.com/clutch-kit-3-pc-tr4a-to-tr6.html

Fred

Fred,
Their cheaper kits have the suspect release bearings. This kit is probably better. Maybe someone will chime in with actual experience.

I haven't taken my trans out yet for the W58 conversion and won't be for a while, so my knowledge is based on reading the Buckeye articles. Edit: ...and almost 20 years with the Toyota trans on my Healey.

https://www.bpnorthwest.com/triumph/tr250-tr6/clutch-components/clutch-mechanical/clutch-kit-sach-german-tr4a-to-tr6.html



Edited 1 time(s). Last edit at 2022-01-17 12:52 PM by steveg2.

The parts are TR except the friction plate. However, the piece the throwout bearing carrier rides on is not. It sounds like you are having someone else turn the wrenches. I would stress to whoever it is to really measure things closely and consider possible problems. In no certain order: 1. throw out bearing carrier cocking and grabbing on the tube that it rides on. (consider machining a proper tube, using a brass carrier, chamfering/polishing edges). 2. Put grease fittings in bell housing where crossshaft rotates 3. Inspect crosshaft and securing bolt for the fork. If the crosshaft/fork is threaded and the whole length of the bolt is threaded, it will eventually fail in shear. (consider replacing all of these so that there is a smooth shank on the bolt to transfer the loads). 4. the fork is relieved to clear the W58 bolt, if you replace it to solve #3 make sure that it clears. you may want to safety wire the fork securing bolt. 5. Measure how deep the input shaft engages the bushing in the flywheel. The HVDA conversion puts a steel extension/bushing on the end of the W58 input shaft. This increases both the length and the amount of bearing surface (diameter) supporting the input shaft. You truly need the whole of that input shaft bearing surface supported, otherwise the input shaft will be worn badly. There is a difference in the length (along the drivetrain axis) of the bellhousings (HVDA vs Eagle). If you include the extension above, it is almost 1/4” difference in the engagement of the flywheel bushing.

Having said all this, I found that the mounting holes of my Eagle bellhousing were of tighter tolerance than of my HVDA bellhousing. Also, consider a way of securing at least the upper starter bolt in the bellhousing with the threads facing forward. This makes replacing the starter much easier in the future. Don’t forget the two locating pins. Measure your thrust washer play too.



Edited 1 time(s). Last edit at 2022-01-17 11:16 AM by HuhReally.

Ok...thanks for clarifying and assuming that replacement is needed, is this the right one: https://www.lmperformance.com/797479/16085-stock-competition-clutch-oe-stock-replacement-clutch-kit-toyota-supra-30l-non-turbo-w58-transmission-7mge-2jz-ge.html

And the release bearing for the TR6: https://www.bpnorthwest.com/release-bearing-tr4a-to-tr6.html?gclid=CjwKCAiAxJSPBhAoEiwAeO_fPwh3_HcFVV-3p92CAtHB80O5jFRXjOZtxN8LKoV3qmZdZOmnPBRmrRoCtaMQAvD_BwE

Does my mechanic also need to purchase the TR6 Clutch Release Fork, Release Bearing Collar and Clutch Fork Pin?

Appreciate the advice here!

Fred

I would be seriously flabbergasted if any Supra parts would fit. That would be uncanny. Go cruise around the Moss listing for HVDA stuff. As for buying parts first, big unknowns until you can visually inspect everything. If you end up needing a new input shaft for the W58, I would suggest contacting Marlin Crawlers
https://www.marlincrawler.com/

Craig,
If Fred's already running the Eaglegate kit, isn't the stuff you mentioned already handled?

I'm thinking, probably all he'll need is the uprated Gunst bearing and a new Toyota clutch disc.

I've been running a Toyota setup on my Healey for almost 20 years. For the Healeys, the Toyota discs tend to be a little thin - not too much wear before you reach the lower spec for a stock Healey disc. So Marlincrawler might have uprated discs. Their delrin shifter bushings are a good thing - more rugged than the stock rubber item.

Edit: here's the Eaglegate kit:



Edited 3 time(s). Last edit at 2022-01-17 12:50 PM by steveg2.

Fred - No to both those. Don't buy one of the cheap release bearings! Don't buy a Triumph disc - if you need a disc at all, you need a Toyota disc.
You probably have very few miles so in all likelihood you do not need a pressure plate.

Gunst-type German release bearing:
https://www.bpnorthwest.com/triumph/tr250-tr6/clutch-components/release-bearing-hd-and-bronze-sleeve-tr4a-to-tr6.html

Friction disc from RockAuto:
https://www.rockauto.com/en/moreinfo.php?pk=6084411&cc=1278514&pt=10605&jsn=10403

The Supra has far more power than a TR so an OEM replacement disc should be fine.

Craig's point about not ordering parts until it's apart is well taken.



Edited 2 time(s). Last edit at 2022-01-17 01:17 PM by steveg2.

Fred,
If all this seems overwhelming, strongly suggest reading the Buckeye Triumphs Clutch articles - they will allow you to understand all this even with someone else doing the wrenching.

https://www.buckeyetriumphs.org/clutch

Re friction disc, what do we know?
1. It has to have Toyota splines not TR splines
2. It has to be of a diameter that fits the TR flywheel and pressure plate without interference.
From the Moss Motors website “ The HVDA conversion kit supplies a hydraulic throwout bearing assembly and a clutch disc. The clutch disc is specific to the HVDA kit because its splines are configured to match up to the Toyota five-speed transmission’s input shaft. A Triumph clutch plate will not work. ”

Instead endless speculation, Fred, who did the inspection report? Does the inspector have experience with these conversions? Why was a throw out bearing recommended? What symptoms of operation indicated a throw out bearing problem? How long has the conversion been in operation? And, has any of the components been inspected since installation and the development of some kind of mechanical problem?

(deleted - incorrect info)



Edited 1 time(s). Last edit at 2022-01-18 12:33 PM by steveg2.

I had one of the first Eagle kits. Bill sourced the clutch discs from McCleod. Special order for center spline and diameter. I ended up with a replacement as the first one had some bad rivets. I had the first one rebuilt by McCleod with Kevlar pads. Later, I got a replacement disc from the gentleman Bill sold the project to. Yes, it is a Toyota disc but it had been turned on a lathe to a smaller outer diameter. Since I am not at home I can’t measure the outer diameter of my spare disc but I highly suspect it isn’t the full 9.250” of a Supra disc. In your picture, that disc looks suspiciously the same as the turned down disc I got. To wit, the outer rivets aren’t even on the friction pads and it isn’t perfectly circular. How about a friendly wager of $50?

Ha ha, serves me right for being smug. Mine's turned down to around 8-3/8".

Healey's easier because the 9-1/4" Toyota disc fits without mod.

Is there a favored pressure plate for this conversion?



Edited 2 time(s). Last edit at 2022-01-17 06:43 PM by steveg2.

Steve...thanks so much for taking the time to actually create a diagram of the Eaglegate configuration (googling doesn't yield anything much), clarifying each part. Super nice of you!

Fred