Clutch Pack, Carrier & Oil Pump Torque

[Mike V]

All,
I'm in the process of Clutch Pack R&R, inspection and repair of the 81 R65 restoration project and wanted to run some final torque values and re-assembly procedures by everyone for their feedback. The clutch pack came apart with no problems except for the normal grunge from years of non-use. Friction plate, pressure plates and spring came out with no problems and cleaned-up quite well. Pressure plate surfaces were almost perfect after cleanup with no scores. I did find some very small pitting in a localized area that seems to be minimal. The friction plate was measured with micrometer in 10 different positions for which the average thickness is 5.50mm, above the minimal 4.50mm threshhold but less than the 6.00mm new thickness. My questions are regarding the reassembly and final torque values. Here's what I've come up with after some research - more still to do.
1.) Flywheel (Carrier) Bolts 11221262060 M11x1.5 / Bum says no need to replace. Torque value=75-80 ft.ib. dry no locktite.
2.) Clutch Assembly Bolts (6) 21211338680. I'm replacing these with new washers. Torque value = 7.5 ft.lb. (?)
3.) Oil Pump Cover Bolts 07119913464 M6x16 Torque value=7 ft.lb. w/blue locktite.

I'll be replacing the rear main seal, and oil pump seals.  Any advice, directions and/or corrections to the above is appreciated. Link to photos...
 http://s428.photobucket.com/albums/qq8/gruntyman66/81%20R650%20Restoration/Engine/?albumview=grid

Yes, front of crank will be blocked during flywheel/carrier removal and re-assembly.

Mike V.

[Bob_Roller]

Mike,

I think you've got it under control, with those torque values .

I have gone with higher torque value for the 6 allen head bolts, that hold the pressure plates, clutch disc, and spring .

Couldn't find any official torque at the first time I replaced the bolts, I went up to 15 ft/lbs, before I started stripping out the allen head .

[Mike V]

Thanks Bob. Bum's site is a bit cumbersome on the specific subject regarding the 81+ 650 assembly and torque values. I may contact him tonight for verification on the List.  I also remember Oak specifying 8 ft-lb for these with blue locktite, I think. Is your procedure with or without blue Locktite for the 6 clutch pack bolts? There also seems to be two different sides of the fence regarding replacement of the flywheel (carrier) bolts. Bum's feeling is it's not necessary since the flywheel (carrier) bolts don't reach their elasticity limit.  My tendancy is to replace if questionable, small cost and cheap insurance. Any personal opinions on that you can share?
Appreciate the help.
Mike V. / San Diego
ABC-MOA-AMA

[Bob_Roller]

I replaced the bolts, and the lock washers, when I replaced the entire clutch assembly, and I used blue Loctite .

I don't know if you have heard of Southland Clutch, in National City, but they advertise in the Airheads monthly newsletter .

I had the clutch disc relined, and the pressure plate, and pressure ring machined .

The workmanship looked top notch, but I had nothing but problems after wards .

The machining job on the plates was poor, at the very least .

I'm no machinist, but I think I could have done a better job .

[Mike V]

Interesting! Yes, I'm aware of that local establishment and my plans were to take the entire assembly to them. I've heard mostly good, and some bad. That complicates things a bit and makes me a bit tentative. Can you share some information about the specific problems you had after the work?

Maybe I'll just throw a new friction plate in and button it up. The presure plate surfaces look almost perfect - did you view my photos?

[Bob_Roller]

I had no problem with the rework of the clutch disc, Spicer friction linings were used .

Both pressure plate and pressure ring, were machined in a cone shape, with the outer edge being the highest, also the pressure plate was also machined with the cone at an angle, when viewed from the side .

I had at best 3/16ths of an inch contact between the clutch disc, and the plates, at the outer edge .

I had transmission problems as well, I had Motorworks do an overhaul of the transmission at the same time, they are only a half mile from Southland Clutch, the shift shaft seal was installed very crooked, and I could up shift to 5th gear, but could only down shift to 4th gear .

When I pulled transmission off to look things over, I found the pressure plate and ring, had turned blue in the contact area, only had 3 miles on it .

So that was my experience, from what I've heard, I am one of the few, that have complained about their workmanship .

But if I hadn't had transmission problems, I don't know how long it would have been, before I noticed the poor machining job .

If you know anyone that has had this work done, and can't get the proper clutch lever free play, you need to replace the adjustment bolt at the back of the transmission to one that is 4-5 threads longer, to make up for the metal removed during machining, and also the increased thickness of the clutch disc .

[Semper Gumby]

Hi Mike,

I thought the Clutch assembly bolts on your '81 were 8mm not the 6mm of the 1979 and 1980.  I think the 8mm clutch assembly bolts go to a higher torque, but I am out of town and not near my clymer/BMW workshop manual.  Home late tonight....The torque value you quote 7.5 ft lbs looks right for the smaller 6mm clutch assembly bolts (with blue locktite).

TTFN,

[Bob_Roller]

Big problem with trying to get to a higher torque value, is that the bolts aren't hex head bolts, they are allen head, and the depth of the allen key hole is only 3-4 mm, they strip out quite easily .

[Semper Gumby]

Allens?  There aren't supposed to be allens holding the clutch together.  Have you got the right bolts?

D@mn - Those are allens.  I'll shutup now.

[nhmaf]

I didn't have a problem getting mine up to 15 ft-lbs on my 82 (8mm allen-head bolts).   I DID put a small amt of anti-seize on the threads, BMW recommended a bit of oil and not to put them in dry. I think that 13-15 ftlbs is the spec on the 8mm bolts, I wouldn't go above it though.
Use a good bit in your torque wrench, too