RE: [xj-s] Re: (xj-s) Oil consumption and Overheating

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

UK prices. C41102 listed at Jag price of £14.40UK, and good aftermarket from
FB Components at £8UK.  Can't find CCC6993 listed anywhere (?).  Your US
price of $14.96 looks good.  But where you get ripped off in the US on Jag
prices, you more than make up for on aircon compressors from Harrison and
GM400 auto boxes (boy do we get stiffed here or what!).

Craig

-----Original Message-----
From:	owner-xj-s@jag-lovers.org [mailto:owner-xj-s@jag-lovers.org] On Behalf
Of Richard F. Dixon
Sent:	29 July 1998 17:18
To:	xj-s@jag-lovers.org
Subject:	[xj-s] Re: (xj-s) Oil consumption and Overheating

>Thanks for the interesting thoughts, Richard.  What sort of engines do
you
make at Cummins? - sounds like truck diesels.

Your observation on valve rotation is extremely logical, and is perhaps
the
design intention.  The wear pattern on the buckets is certainly
consistent
with the bucket rotating, but the valve stems seem to wear  down one
side
only.  This would only be consistent with the valve not rotating, and
also
having some sideways force in the direction of cam rotation, transmitted

through the sliding contact of the leading edge of the cam.  The degree
of
wear, is however small, with stem clearances well within spec after 150
-
200k miles.

Craig Sawyers<

Craig,

Cummins is the world's largest independent producer of diesel engines
from 80 to 2000 hp. We have annual sales to the tune of  $4.6 billion.
We produce engines for all kinds of applications.

Having only been a Jaguar owner for 3 months, I thank God that I don't
have first hand knowlege of the valve wear patterns in the V-12 engine.
I can only comment on the design intentions which are very much in line
with current industry standards of today. The talk of improved
lubrication, positive rotators (which would lower the redline ~2000
rpm), and better seals, seems to be addressing a problem which you seem
to agree doesn't exist.

The issue of dropped valve seats is another matter however. I believe
that when it is all over, you will find that dropped valve seats are
caused by low coolant levels which result in localized steam pockets
being formed at the exhaust ports. Low coolant levels are not always
shown on a temp gage. Only last weekend I had a pinhole leak in my lower

radiator hose. I didn't know it until I saw a puddle of coolant under
the car in the movie theater parking lot. After replacing the hose, (a
real S.O.B.) I refilled my cooling system and started driving the car.
On my way home from work the next day, I noticed the temp guage reading
at the bottom of the N. This was higher than it was after my previous
cooling system rebuild. (halfway between C and N). When I checked the
coolant level it needed another half a gallon of coolant due to the air
being bled out. Makes you wonder how low it needs to be before you would

sense a problem. And makes you wonder how low it could go before there
is a problem. See, Jaguar knew what they were doing when they included a

coolant level indicator as well as a temp. gage. Now I wonder if mine
works?

>That is one EXPENSIVE lower rad hose!!!  It will probably be cheaper
for the
guy to buy a new car.  Re-build of a siezed V12 will cost many, many
thousand dollars.<

BTW, when I bought my lower radiator hose, I got wildly varying prices.
XK's unlimited wanted $US 11.95 for p/n C41102, which was stamped on the
one in the car. Reasonable. The Jag dealer here said that p/n was
superceeded to CCC6993 which was $US 36.95 (outrageous) and he did not
have it in stock! Apparently they don't keep much in stock. They had 5
xjs's in the lot for service. I asked why they didn't keep hoses in
stock, and the reply was "We only keep parts in stock for later model
cars" (mine is an '82). I checked XK's Unlimited catalog and CCC6993
fits 6.0 xj-s and is $US 32.95. Needless to say, the dealer won't get
much of my business. Called a local import parts store and she said $US
14.96 and I can have it tomorrow. Order it! ( I know where I'm shopping
now) When it comes in, guess what part number it has on it. Both C41102
and CCC6993. And it fit perfectly. Go figure!!!

--
Richard F. Dixon
Engineering Test Services
Cummins Engine Co.

---

References:

• [xj-s] Re: (xj-s) Oil consumption and Overheating
• From: "Richard F. Dixon" <rfdixon@chs.cummins.com>

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