I know this subject has been talked about but I would like a
direct answer from a few of you experts. Is it worth the extra
money to use the rear main conversion kit with the machining of
the crank plus the Teflon front seal that I have read about. I am
rebuilding my xk140 engine. I am not making a high performance top
notch restoration. I just want it to put around in and be
reliable. Of course I would rather not have it leak. I can live
with a few drops but I don’t want it to be like my Harley panhead
either.
Thanks for your info @HOLDEN–
HOLDEN
Houston Texas, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from HOLDEN sent Tue 8 Nov 2016:
Holden,
I hope I do not step on any toes here but having been in the
seal business for way to many years I have found the the
following:
If you accept that in rotating equipment there is no such
thing as a perfect seal only a ‘‘controlled leak’’ it then
becomes a decision on how much to spend on getting as close
to a perfect seal as possible. What ever the approach taken
it is important to have a fluid film under the lip to
function as a good seal with any kind of life longevity.
In my opinion Teflon lip seals are great only if the
rotating element has the proper surface finish and
‘‘directional grind lay’’ with ‘‘surface hardness’’ of Rc 52
minimum.
This means that unless your crank shaft is ‘‘case hardened’’
or a hardened ‘‘Speedy Sleeve’’ is used under the seal lip,
you likely will experience grooving of the shaft and have
early failure. Teflon has great low friction, temperature
and chemical resistant characteristics but will embed
contaminates into itself and become a good grinding surface,
this is why a hardened surface is required.
I just received my oil pan gasket set so I can replace the
front leaking seal and am going to use the supplied Buna
(rubber) seal. At this time trying figure out if the pan
can be removed with out dropping the front cross member, I
sure hope so?
Does any one know where I can get a BW-66 shift shaft seal
‘‘RTC-1704 or RTC-0020’’? If not I may have to make one, and
as a surprise I may have to make it out of Teflon.
In reply to a message from KLJ sent Tue 8 Nov 2016:
LOL. I enjoyed that explanation. Exactly what I was looking for
and it sure makes a lot of sense!–
HOLDEN
Houston Texas, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from KLJ sent Tue 8 Nov 2016:
I believe that you will find that the XJ6-S3 factory teflon front
seal comes with a hardened, polished, sleeve the the seal lips
ride on. The sleeve, which rotates with the crankshaft, has an
internal o-ring that seals the sleeve to the crank–
The original message included these comments:
This means that unless your crank shaft is ‘‘case hardened’’
or a hardened ‘‘Speedy Sleeve’’ is used under the seal lip,
you likely will experience grooving of the shaft and have
early failure. Teflon has great low friction, temperature
In reply to a message from HOLDEN sent Tue 8 Nov 2016:
The rear seal conversion is a ‘one way ticket’ if it
doesn’t workout then you have a non standard crank’. a top
engine builder here in the Uk did remind me that ‘‘there is
nothing wrong with a properly installed rope seal’’
Which he did for me and it doesn’t leak. Like a lot of
issues these daze, find the correct part and install it
properly and you wont have a prpblem.
Regards
PAD–
The original message included these comments:
I know this subject has been talked about but I would like a
direct answer from a few of you experts. Is it worth the extra
money to use the rear main conversion kit with the machining of
In reply to a message from Phil.Dobson sent Tue 8 Nov 2016:
Hi I have 2 E types, and am restoring a 420. All three have
rear seal conversion, perfect seal, no. but better than
before. Front seat, converted to the teflon OEM front seal,
it eventually leaked, so all three have rubber front seals
and none leak. Save your money and go with the original seal
in the front.