Crankcase bolt torque

[kmev]

I'm getting ready to shim my crank and close the crankcase. What are the torque specs on the crankcase bolts and screws?

Is there someplace that lists all the appropriate torque settings that aren't listed in manual?

Keith

[JimF]

I sure hope some answers for this question start to roll in. Torque values, special tools and shimming is the kind of information the website needs to put on an engine tech page.

Those of you into old BMWs likely have a copy of the Clymer manual on R series airhead BMWs. You would not want to drop that BMW manual on your foot. Besides all the illustrations it has torque values for most if not every fastener used on the engine, transmission, swing arm and final drive.

We with single cylinder Ducatis are given very little useful information in the available and very thin manuals first published forty years ago. The last thing we want to do is strip a thread on these old engines or have them shake apart in service.

Jim Franzen

[kmev]

That's why I was dissapointed when Tom Bailey's book wasn't published - I hoped it would include a lot of the stuff missing from the Ducati manual.

[JimF]

Hi Keith,

I just forwarded your question in an email to Tom - hopefully he'll respond and you can move forward.

It would be nice if Tom Bailey would join this forum, as well as Frank Scurria and some others I can think of. We could ask them to join, but it would be better if they want to join, and I think they will if the correct foundation is laid out in this site. It's too difficult to bounce around between mailing lists and forums on a daily basis just to answer questions out of the goodness of one's heart. But I do think people that want to share their knowledge and information will go where they think their contributions will serve the greatest good, and someday that may be this site.

[DewCatTea-Bob]

" It would be nice if Tom Bailey would join this forum, "

____ I've received an email from a very-high (top) & trust-worthy source that he was already aware of this w.site & registered here, by the time I myself was!
So it would seem that you Jim, would only have to look-up the given email-addresses of a few of the earlier members here, in order to pin-down which user-name is his.
__ I really would not expect ANYONE who has any related books to sell, to just volunteer any related info which could possibly cut into sales!
__ It would be nice to compile a wish-list of information that's not available elsewhere, with hopes that all the answers would then get published within the next publication by such a fine source of related info! _ But that's probably just a wish.


____ As for the torque-figures for the motor-case go, I myself always just went by 'feel', as good mechanics just have The-Knack for such!
__ I recommend that the two main 8mm-bolts be fairly tightened (but not yet fully torqued), before fully torquing any of the 6mm-screws, AND, to tighten each screw just a little at a time, working around the clock several times! _ Then after all the 6mm-screws are fully tightened, then go ahead & fully torque-down the two main bolts (at the base of the cylinder).
And if ya really care about the motor-case, I suggest that ya find & use screws which are 3 to 5mm longer than stock, and also made of aluminum.
And also, always be sure to use a greased tap to clean-out all those (blind-hole) threads, before-hand!
__ If ya still feel the need to use a torque-wrench (that's accurate in the first-place), then find a good shop-manual for some old Honda, and just use whatever figures are given for it where the same sized screws (with a similar number of threads) are used for it's motor-case.
That'll likely put you in the ball-park better than just guessing!
I really wouldn't worry about it all too much now at this point,, cuz you'll be having to reset them all again anyhow, after the motor has been ran a number of times, (due to vibration combined with heat-up & cool-down periods causing the screws to get loosened).


GoodCheers,
-Bob

[JimF]

Tom Bailey writes...

"Hi Jim,

Torque specification is described in the workshop manual as --"Tight"..
(Smile) I note that in attending 4 Berliner Ducati schools, all of
which were about as half ass as the one described in the book, at no
point were torque specifications ever discussed. Further in observing
mechanics both at our shop and at the races, I never saw anyone using a
torque wrench in the assembly of a Ducati engine, nor did I ever use one...

Interesting in that torque wrenches were religiously used in the
assembly of English engines...

I do not think the stretch factor ( which is the reason torque specs are
usually given) is critical with regards to joining Ducati cases. The 2
M8 bolts are there to stabilize the case for the cylinder head bolts
and the M6 allen heads are there to provide oil tightness. You would
think the cylinder head bolts would be somewhat critical and have a
torque rating but they are likewise specified as "Tight". Perhaps the
Aluminum construction of all the pieces (save the cylinder) provides
enough expansion that it is not a problem...

Torque ratings on M8 8.0 bolts (as used on the 160 - 350 narrow cases)
are in the area of 17 to 18 ft. pounds. I would think 10 percent less
would be adequate...
Torque ratings on M8 10.0 bolts ( Widecase engines) are in the area of
25 ft. lbs. - Again at least 10 percent less if I were doing it with a
torque wrench...

Stainless steel bolts (often used in modern restos) are weaker than high
carbon steel and available in a wide variety of different alloys of
different strengths. To find a torque spec for those you weed need to
know the alloy...

As far as the M6 allen heads -- use a two inch long allen wrench and do
not overdo it. Strip the treads on the bottom of the oil pan and oil
will leak out the srcew hole! We always coated the center gasket with
olive oil. When beads of oil oozed out of the center seam we figured it
was tight.

One thing you do NOT want to do is use the screws and bolts to bring the
cases together - this will warp the cases. With a wood mallet and a
soft wood rod tap the cases until they are in contact, then put the
screws in... Use an X pattern for tightening the allen heads. Put the
M8's in last.

In other words -- I don't know...and I continue learning that I don't
know more everyday.

Tom"