RE: Re: Head Stud and Nut Torqueing

["John Dancoe" <jdan@xxxxxxxx>]

Tom Cutter wrote:

>I have heard of pulled studs in  Oilheads, but only saw one, and that was an
>accident where the jug was pulled  and the block was otherwise damaged.

Tom, you made my day!

Having heard these horror stories for years, I've been wondering when mine
were going to fail (May '93 R1100RS).

Not that I've been doing a lot of head service; I had one gasket replaced
under warranty back in the '90s, and did the other one myself last year. The
original (vintage '93) gaskets were known to have a problem; presumably now
I'll have no need to think about them for a long time (and anyway, I've only
got 23k miles to go before I'll [probably] buy a R1200S!).

FWIW, here is a conservative approach that I'm betting will satisfy both Mr.
Cutter AND Mr. Barkow.

When I did my head I was VERY concerned about pulling the studs out, and this
was the first time I'd ever used the angle method so I was a bit nervous about
that also. So this is what I did:

1. Referred to my airhead manual to determine the ballpark for a cylinder head
torque.

2. Used my click-type torque wrench to MEASURE the torques of the nuts BEFORE
I removed the head. That is, I "sneaked up" on the torque, starting with a low
torque setting and increasing it in small increments until I found the point
where the nut just started to turn. This is a bit dangerous, as it inherently
torques the nut a little tighter than it was; but done carefully, the amount
of potential overtorque will be pretty small, on the order of 1-2 ft-lbs.

3. Obviously step #2 is not an option if both cylinder heads have already been
removed.

4. When I did #2 I found the existing torques were very consistent, and in the
same ballpark as an airhead. I was expecting a somewhat higher torque setting
than an airhead but don't remember what I actually found; if I think about it,
I'll check my notes when I get home tonight. Tom's 42 ft-lb number sounds
about right.

Remember: I was measuring whatever had been done by the dealer at the break-in
maintenance (in those days, an angle-method head retorque WAS specified at the
break-in maintenance), and however much it had changed in about 70k miles
since then (apparently, not much).

5. Now I had a pretty comfortable feeling about what the torque setting should
be. I dialed my wrench up a few ft-lbs; this was my "DO NOT EXCEED" setting.

6. I then proceeded to perform the tightening sequence just as Tom (more than
once I think) has described: using the angle method on oiled threads. The
torque wrench never clicked, no studs pulled out, and I went for that beer
with a warm fuzzy feeling.

Good luck!
John Dancoe
Plexus Systems
248.391.8000
248.249.1545 cell
248.393.1799 fax
jdan@xxxxxxxx

------------------------------