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Re: TD's leak oil? /13

Subject: Re: TD's leak oil? /13
From: Geoff Love <>
Date: Fri, 13 Dec 1996 22:56:24 -0500
Jarl/Carol wrote:
> Geoff Love wrote:
>  the seal between the rear
> > bearing cover and the sump gasket, a crude asbestos rope type, has not
> > been correctly fitted, or has become dislodged during re-assembly.
> > These seals are awkward to fit properly, and time must be devoted to
> > their correct placement, or you will get what you have, a pourer, not a
> > dripper.
> > The correction is to remove the sump pan, and rework the rear oil
> > slinger/rope seal gaskets. It may be necessary to fit a new oil slinger,
> > and mate that by hand lapping to the crankshaft in order to obtain as
> > oil free a union as possible. There is also a new proprietary rear oil
> > seal on the market which will work better then the rope type. A word of
> > caution, however.  Make sure that the fault indeed lies at the rear end,
> > and the leak is not caused by some other problem such as a leaking oil
> > transfer pipe to the cylinder head.  This will be obvious by visual
> > inspection, when the motor is running.
> > If you have any further queeries, contact me directly. I speciallise in
> > the restorations of these treasures and, while I don't know everything,
> > I do know a bit and will be glad to offer you free advice.
> >
> > Geoff Love, The English Connection.
> Free advice is worth what you pay for it! I don't like to disagree, but
> Geoff has so many things wrong here, I really have to comment. There is
> NO asbestos rope seal at the rear of the XPAG engine, there IS one at
> the front. He's talking about the rear cork pan gasket. You cannot
> "remove the sump and .... fit a new oil slinger" and expect things to
> work. In order to properly fit a new slinger, you MUST remove the
> crankshaft. The problem with the slinger (actually the Archimedes spiral
> of the crankshaft) is usually more related to wear of the rear main
> bearing cap after years of running with worn out main bearings. You
> don't "lap the slinger", you fit it with even clearance all around,
> realizing that it only seals the top half of the spiral (the worn main
> cap is the lower half). After fitting, you drill for dowels and install.
> While the external pipe that feeds the rockers is a possible source, a
> MUCH more likely source is a poorly installed core/freeze plug at the
> rear of the rear cam bearing. I've pulled pans on engines such as yours
> and found the plug lying next to the flywheel.... One other thing can
> make T types leak like a sieve when there is NOTHING WRONG. If the oval
> vent plate at the top of the bell-housing is installed upside down, the
> "turbine" effect of the flywheel/clutch creates a vacuum and sucks the
> oil out of the rear main. There is a slot at one end and when installed
> correctly, it actually slightly pressurizes the area and helps keep the
> oil in.
> We can all agree: you didn't get what you paid for-a properly rebuilt
> engine. However, ALL engines have foibles, I wouldn't know the tricks to
> make a Chec 283 "live" and the best Jaguar mechanic in the world hasn't
> had the chance to learn what the particular problems of a TD would be.
> Jarl de Boer  (493 T type engines later)
You are absolutely right in everything you say.  I apologise for my
errors. Tiredness is my only excuse, if it is permissible.  The seal at
the rear end is cork, and is squeezed into position by a 'sharp' edge on
the sump pan.  It must mate with the block casting on it's ends, and
must mate carefully with the small cut outs in the pan gasket and/or
vice versa.  The oil slinger is the actual Archimedes screw cut into the
end of the crankshaft, and the device which helps the oil to return into
the sump, via this screw, is a semicircular aluminium plate retained at
the rear end of the block by 3 small bolts, and positioned by dowels.
The wear you speak of is, as you rightly state, often caused by the
crankshaft running out of true due to wear in the main bearings, and the
worn main bearing cap. I have found, however, that by carefully lapping
the aly plate to the slinger it is helpful in ensuring a better control
to the oil leak problem.  After the 'lapping'  process, it is necessary
to adjust the holes through which the retaining bolts and locating
dowels pass in order to enable the plate to be moved into closer contact
with the slinger. In other words, to 'tailor' the plate to the
circumference of the worn screw. And, yes, the crankshaft must be
removed to carry out this work.  Only then, when the flywheel is also
removed, is it possible to replace the cam shaft bearing's core plug.
As I said in my first communique on this subject, I don't know
everything, I know a bit. I have just learned, thanks to Jarl, what is,
to me, a fascinating tidbit, namely the part about the oval vent plate.
That kind of knowledge comes only from years of experience, and I can't
claim to have anything like 493 T type engines under my belt, but I do
have a goodly number of first prizes awarded to owners of T-types which
I have restored.
Thanks for the tidbit and the corrections, Jarl.

Geoff Love, The English Connection.

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