RE: [xj-s] Torque Wrench Settings

["Craig Sawyers" <craig@sawyers.demon.co.uk>]

Sorry about the name confusion, Kirkbert.  Yes, a fine thread will develop
more tension than a coarse thread for a given torque.  M8 is metric coarse,
and is very close in spec to 5/16 UNC.  The corresponding metric fine thread
is very close to UNF.  My engine clearly came from a hybrid era, because my
block is UNC and UNF, and my heads are metric.  Engine dates from 1984.

On my engine all tappet block cap heads, studs and nuts are M8 coarse, so no
confusion on mine.

My service manual is AKM 9006 Ed 5.  Copyright date is 1988.  What is yours?

In this operation 12.13.29 and 30 (tappet block LH and RH remove and refit)
specifies "smear mating surfaces of tappet block and cylinder head with
Loctite 573"

In answer to your final question, not yet (hold breath, pray....)

Craig Sawyers

-----Original Message-----
From:	owner-xj-s@jag-lovers.org [mailto:owner-xj-s@jag-lovers.org] On Behalf
Of Kirbert
Sent:	12 July 1998 15:47
To:	xj-s@jag-lovers.org
Subject:	RE: [xj-s] Torque Wrench Settings

> From:          "Craig Sawyers" <craig@sawyers.demon.co.uk>
>
> Kirkby - all the bolts and nuts on my 1984 HE were M8 (cap heads and nuts
> alike).  So I did 'em all up to 9lb.ft.

Why do you call me Kirkby?

I dunno what M8 means, but wouldn't a coarse thread bolt develop a
different amount of tension when tightened to the same torque as a
fine thread nut?  It would seem logical to me that all of these
fasteners need to be torqued to provide the same amount of tension,
which would probably be a different torque value for the coarse
thread bolts.  But I dunno how to figure it, given that bolt torques
supposedly include a considerable number of factors such as thread
friction.

> On sealing the tappet block, I agree that an O ring (Viton, of course)
would
> be technically the best solution.  But I wouldn't use Hylomar.  The manual
> specs Loctite 573.

AHA!  We need to be discussing this!  My copy of the Jaguar Repair
Operation Manual, section 12.13.29 step 7 as well as 12.13.30 step 6
says "Smear mating surfaces of tappet block and cylinder head with
Hylomar."  I've already purchased a tube of Hylomar in preparation
for reassembly.  Is my ROM obsolete?  Do later manuals provide
improved instructions?  Do I need to put a correction in the Book?

>  I couldn't easily get that, but I used 574, which the
> loctite specs have as almost identical.  It is an orange paste called
> "Flange Sealant"

Let's ask something important:  Does it leak?

 -- Kirbert      |     If anything is to be accomplished,
                 |     some rules must be broken.
                 |          - Palm's Postulate

---

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• RE: [xj-s] Torque Wrench Settings
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