Randy's RCR40 MKI

Neil

Supporter
Learned something new this week about the Quaife transaxle. Turns out, a base transaxle order does not include the clutch lever assembly (fork, bearings, shaft, etc.). Those parts come as a package from Quaife for an additional £599.50 (QKE62G001). Fortunately, Bob Wood at Safir was concerned that I might have not included those parts in my order from Quaife and called. Turns out Bob has a more suitable set of parts ($45 less at current exchange rates). Safir’s clutch lever assembly has roller bearings instead of bronze bushings, the lever shaft is a bit longer, and it includes seals. Anyone combining the Quaife with Safir’s clutch package also needs to include Safir’s $236 clutch shaft. There is a one spline difference between Quaife’s shaft and the shaft that fits Safir’s clutch.
Porsche made a bonehead error on their G50 throw out shaft bearings. Needle bearings were a terrible choice- any experienced engineer knows that needle bearings are suited for continuous rotation but not for limited angular motion. The grease develops a "channel" with repeated back and forth motion and the resulting lack of lubrication that caused eventual failure. The replacements all had solid bronze bearings. I would be very leery of roller bearings in that application as well!
How a company (Porsche) with such experience could have made such a bad mistake is beyond me. On second thought, look at their rubber-center clutch fiasco. :mad:
 

Randy Folsom

Supporter
Porsche made a bonehead error on their G50 throw out shaft bearings. Needle bearings were a terrible choice- any experienced engineer knows that needle bearings are suited for continuous rotation but not for limited angular motion. The grease develops a "channel" with repeated back and forth motion and the resulting lack of lubrication that caused eventual failure. The replacements all had solid bronze bearings. I would be very leery of roller bearings in that application as well!
How a company (Porsche) with such experience could have made such a bad mistake is beyond me. On second thought, look at their rubber-center clutch fiasco. :mad:
I read somewhere here about those needle bearings. I will ask Bob if there are similar concerns with Safir’s. Certainly, it is an easy fix to use bronze bushings. Thx much.
 

Randy Folsom

Supporter
Did you build that kayak Randy? Looks gorgeous!
I did. I also built a canoe and wrote a how-to book for that:
IMG_3069.JPG
 
Porsche made a bonehead error on their G50 throw out shaft bearings. Needle bearings were a terrible choice- any experienced engineer knows that needle bearings are suited for continuous rotation but not for limited angular motion. The grease develops a "channel" with repeated back and forth motion and the resulting lack of lubrication that caused eventual failure. The replacements all had solid bronze bearings. I would be very leery of roller bearings in that application as well!
How a company (Porsche) with such experience could have made such a bad mistake is beyond me. On second thought, look at their rubber-center clutch fiasco. :mad:


Every U joint I have ever seen has this same affliction. Is it really such a problem?
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
Every U joint I have ever seen has this same affliction. Is it really such a problem?
Most “replacement“ U-Joints have a grease zerk installed and you can periodically refresh the lube in the joints. Also, the heat involved with U-Joints will soften up the lube to the point where it will redistribute between the bearings if the bearing was assembled with lube properly to begin with. Not much heat involved with the release bearing shafts on the P-Trans.
I agree with Neil as there are places and times where solid bushings make more sense.

beautiful craftsmanship on the canoe & kayak!
 
The clutch throwout shaft usually (maybe not on a GT or a rear engine car) has an exhaust pipe and cat near, and the rear U joint is in the back in fairly clean air. I'm not convinced a ujoint on a driveshaft runs hotter than the needle bearing on the shaft. In both cases I would think they're close to the temp of the bellhouse or drive shaft yokes, and that's a big lump of metal to dissipate heat into. And the OEM Ujoints that usually last 150K miles without lubrication after manufacture.

Is the problem much a heavier than OEM pressure plate and the bearing spec'ed is of marginal size? Is this common problem on Porsche transaxles in OEM Porsches?

I'm not looking to argue to convince anyone my opinion is right, but rather find the real facts. Just so I don't ruffle feathers as these things can go askew without being face to face.
 

Randy Folsom

Supporter
Please share sources for bushings to fit the Quaife. I am supposed to receive both the transaxle and Safir clutch package this week.
 
They (U joints) absolutely do go back and forth, and they do it once per revolution of the shaft. The whole joint rotates, but the cups reciprocate on the cross the amount the shaft is out of line. I know when used, there has to be some misalignment to not flat spot the needles and point load the cross. Also, they make thousands of reciprocation a minute, and about 3000 per mile. That's 450 million in a 150K miles far more times than the clutch is depressed.
 

Neil

Supporter
They (U joints) absolutely do go back and forth, and they do it once per revolution of the shaft. The whole joint rotates, but the cups reciprocate on the cross the amount the shaft is out of line. I know when used, there has to be some misalignment to not flat spot the needles and point load the cross. Also, they make thousands of reciprocation a minute, and about 3000 per mile. That's 450 million in a 150K miles far more times than the clutch is depressed.
They (U joints) absolutely do go back and forth, and they do it once per revolution of the shaft. The whole joint rotates, but the cups reciprocate on the cross the amount the shaft is out of line. I know when used, there has to be some misalignment to not flat spot the needles and point load the cross. Also, they make thousands of reciprocation a minute, and about 3000 per mile. That's 450 million in a 150K miles far more times than the clutch is depressed.
"U-Joints do not experience the same limited back-and-forth movement." These conditions are very different from the clutch throw-out arm where the rotation is only a few degrees and never varies..
 

Randy Folsom

Supporter
While I am waiting for my RCR40 to arrive, I decided to put my available time towards an altogether different project. Picked this up yesterday. It's a 2007 FFR Mk3 that was last worked on around 2010. Towing it home on an open trailer got rid of most of the dust :) None of the aluminum panels have been attached, which is great since I will be able to clean up the frame.

I am looking for a mild combination set of heads and cam. The ones that came with are a bit peaky. I want more low end torque and less high RPM HP. Suggestions are most welcome.

Front Qtr View.jpeg
Rear Qtr.jpeg


Most of the parts are still in the original boxes
Parts and more parts.jpeg


The DART SHP 351W/427 Dart is still wrapped in wax paper with heads, etc. loosely bolted on
Engine.jpeg


Dart SHP 427W Short Block
Pro Products 6.4" Harmonic Balancer
Comp Cams Extreme Energy 235/240 Hydraulic Roller Cam (I will be getting something else)
RHS 35002 Aluminum Cylinder Heads, 64cc Combustion Chambers, 200CCIntake Ports, 2.02"/1.60 Stainless Valves (I will be getting something else)
Procomp 1.6 Ratio, 7/16 Stub Mount Rocker Arms (P/N 2332)
Elelbrock RPM Air Gap Endurashine Intake Manifold
Holley 77CFM Street Avenger Carburetor
FE Style Coolant Expansion Tank
FFR Radiator & Cooling Fan
K&N Air Filter and Xtreme Filter Top
MSD Pro Billet Distributer
Tremec TKO600 Transmission
Pro 5.0 Midshifter
Quick Time 6063 SFI Bellhousing
Ram 98794T Clutch/Pressure Plate
Ram 1529 Billet Steel Flywheel
Forte's External Hydraulic Clutch Kit
Wilwood Pedals
American Racing Thick Flange Stainless Steel Headers
Gas-N Polished Stainless Steel Side Pipes
SN95 Brakes
Ford Thunderbird Super Coupe Rear Axle Housing
Fresh Trac-Loc Diff (3.55 gears)
TA Performance Diff Cover Girdle W/Stud Mount
Flaming River Steering Rack
Halibrand Style 9"X17"/10"X17" Wheels
Vredestein Sessanta Ultrac 255/40ZR-17 and 315/35ZR-17
SAI Mod
Tubular Rear Control Arms W/Spherical Rod Ends
Adjustable Front Upper Control Arms
Leather Seats, Dash Cover & Door Panels
Russ Thompson Turn Signal Kit
Vintage Air A/C Kit W/Defroster
Autometer Gauges
Dual Black Powder Coated Roll Bars
Super Snake Hood and Liner (still has the Standard FFR Hood as well)
Lowered Rear Body Mounts
Rectangular Tail Lights
Battery Relocation Kit
 

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Randy V

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I’ve built and helped build a half dozen FFR Roadsters now - they can be fun builds. Enjoy!
 
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