G50 fork shaft upgrade test results

[hcoles]

I'm pretty sure these Igus bushings are a long way from Delrin. They look to be modled. I installed one of the high temp. models and they look glass filled. They can be machined, so if the right exact size was found you could machine to exactly what you want. If what I have now works like it is, problem solved. Problem could also be solved using the standard kit, cut the bushings so you have a place to fit the seals and get the shaft hardened and ground back to a ~ 0.001" clearance. I would think that is a lower risk solution. I won't know for ~5 years if my selection of material and clearances was a good choice.

[m110]

Why not go with the factory upgrade? The amount of material removed is minimal. I have never heard of someone buggering this up if they A) have some experience and B) have the factory tool. Mine works great.

[hcoles]

Probably nothing wrong with doing that. I haven't heard of a factory upgrade setup failing. I guess I was afraid of the machining that you show and no invention fun.

[hcoles]

update - running for about one year now, easy duty, maybe 5k miles and no track time. My solution IGUS high temp. plastic bushings and seals along with hard chromed shaft still working great, as smooth as can be.

[r-mm]

Very informative post. Thought id add to it that i just received the Weltmeister kit and the instructions mention sintered bronze and oilite about a hundred times. Wonder if the bushings have changed since your installation or if the instructions have been upgraded.

[HiWind]

Hi Henry - fun thread (for anyone w/o bellhousing problems that is) - how's the 4 year update??

[hcoles]

For those interested in how the Igus bushings and hard chrome shaft solution is working.
~ 7 years later and say 20k miles all is working fine.

[Harpo]

Good morning hcoles,

I can't find the JFM 1622-20 bearing on the IGUS website. Any ideas?

Thanks

David

[Harpo]

Found it

https://www.igus.com/product/?artnr=JFM-1622-20

[LukasM]

Old thread but very informative!

All still good on your end Henry? I have an old G50 that I want to upgrade in the most reliable way before installing.

Cheers,
Lukas

[cmcfaul]

I just did the same upgrade. I put some lithium grease on it. Dont see how it could hurt. Shifts smooth as silk.

Chris
89 Carrera

[KTL]

Take a look further back to see what 88diamondblue’s shaft looked like after 2500 miles of lithium grease. I wouldn’t want to use anything “sticky” that attracts debris (the clutch disc is basically shedding brake dust friction compound) since the shaft is not protected by rubber seals like the factory Porsche assembly.

So I would suggest using something like graphite powder or a dry film lube that you spray on and allow to dry. Can get graphite or an aerosol can of dry film lube from Grainger or McMaster or similar industrial supply location for not a lot of $

[Marc Bixen]

"Ugh, Wheel round, go round and round, why reinvent?"
At Red Line we've been performing the "factory" upgrade since day one. We even do the machining for a few other shops in the L.A. area. NEVER a failure, never a complaint with the factory upgrade.(when done correctly)
I've seen problems with ALL the aftermarket kits, loose bearings, incorrect grease, pedals with effort so high from drag that master cylinders and slaves fail. And even failure of the bosses that hold the bushings, requiring this repair:
https://californiamotorsports.net/collections/porsche-g50-transmission/products/cms-g50-993-gt3-clutch-fork-pivot-shaft-boss-repair

So, Why reinvent the wheel?

[hcoles]

All is still working smooth as butter with the feel on the clutch pedal. I don't have a lot of miles on the new system just 4 years.
I reinvented the wheel because I found the surfaces on the fix-it kit didn't look very good after little use.

My solution might be worse than your "factory" upgrade.
Sometimes a hobby involves the fun of looking for better solutions.
I'm thinking in your business you don't have much to gain by changing something that works. I would probably do the same if I were in your position.

[Tea Tray]

I thing there is a counter intuitive cause of this issue.
I think it’s likely the hard little bits of clutch dust and road dust/dirt become embedded in the very soft oilite.
Then the bushing becomes a low grade “hone” of sorts and digs into the shaft each time you clutch.
Norton Commando’s had a chrome plated shaft and oilite bushings and the dirt embedded bushings would eat through the chrome.
I solved the problem by custom making bushings sealed with o-rings and supplying 140 wt oil from small tubing and the worlds smallest reservoir mounted under the seat.
IIRC the bushings were made of 932.

[hcoles]

^^^ That's why I put in the seals.... hopefully keep most of the clutch dust out.

[hcoles]

Tea Tray - I like your solution - probably more durable than my invention.
I had a buddy that had one of the "ears" break in his G50.
I like the solution link above.