The 'E' Type Forum

Hi all,
Can anyone advise the correct bolts for the above duty (Six off)with respect to:-
(1) Steel grade, i.e., high tensile or not, and
(2) Dimensions, overall length under head,and what length plain and what length threaded......

I've been sent what are essentially 5/16" x 1" set-screws (threaded all the way......) from one of the usual suppliers, and I feel instinctively there should be a small unthreaded section under the head, say 1/4" or so, for this particular (critical) duty.....? Any comments/wisdom most appreciated.......and possibly where can I get the "correct" ones......?
Best regards to all,
Norman.

Norman,
Right you are. I have my engine disassembled for a rebuild and the bolts which hold the clutch to the flywheel do have about a 1/4" unthreaded section beneath the head. Others could tell you if that makes any difference or not.

Maybe this will help:
Nuts, Bolts and Fasteners specs: http://dl.dropbox.com/u/8496016/Fastener%20codes.htm

Norman : this subject came up on Jaglovers just recently , and I discovered that there are variations. For instance, my S1 4.2 Factory parts manual suggests that these fasteners are UFS.137/8R which using the code which David has provided suggests they are 3/8 UNF setscrews which are 1/2 inch long. Yet other people say that their flywheel is drilled for 5/16, which is of course the size you have been sent. All very peculiar, but at least it confirms that setscrews , and not bolts, seem to have been factory fitment . I do wonder whether the 137 is a misprint for 131 which would denote 5/16

I can confirm that mine are 5/16.

Thanks all,
Christopher you are correct re the manual, and for that reason I ordered UFS.137/8R's as per my own Jaguar manual, and 3/8" diam. items arrived. The flywheel is drilled and tapped 5/16", of course, and, on remonstrating with the supplier, they were of the opinion that the manual was incorrect, as you postulated, and the listing should be 131 (5/16"). I am unconvinced, however, that a setscrew is appropriate in such an arduous duty, and the narrow highly loaded land should be plain, about 1/4". The supplier has just responded in, agreement, so the second lot, even at 5/16", were also incorrect. Mark confirms this too, with his current disassembly, thanks Mark........Third lot on the way ex supplier......
Thanks again All,
Best regards,
Norman.

Norman,

the set screws that hold the clutch to the flywheel don't have any shear load to take , the dowels eliminate it . Grade 5 is probably what the suppliers have sent you ? , grade 8 at a guess originally .