In reply to a message from SGLP sent Fri 15 May 2015:
Dear Simon,
Since you are having problems, let’s look at what has been said and
what that means.
1/ You had difficulty inserting the rope seal into the groove.
The groove is sort of trapezium shaped in cross section. You’ll
need to press the seal a bit to make it have a more similar profile
to the groove it’ll have to fit into. To achieve this, the seal
will need to be more pliable. Soak it in oil beforehand as
recommended.
2/ You had an interference fit and the crank was hard if not almost
impossible to turn.
Clearly the seal is way too big and needs to be worked (sized)
further into the groove, such that it offers no resistance to the
crank.
3/ You’ve cut the seal rather than working it further into the
groove.
If the seal can touch the crank, this’ll have the effect of wanting
to make it spin on the crank. As it isn’t packed tightly enough,
it’ll try to do that now, so if it packs tighter after being worked
by the crank, something will give and you’ll find a gap at the end
opposite to the end which has been compressed round by the crank.
To get it started, I suggest you size it to get a basic shape and
then pry it out and put it into the groove with the joins at 12
o’clock and 6 o’clock and then gently and progressively tighten up
and size it. When you think it is well on the way to being sized,
pop it out and replace it in the conventional 3 o’clock and 9
o’clock positions and continue. This way you ought to be able to
compress it to shape, ends included, rather than cut it and face
ending up with a gap.
4/ Larry thinks his tool is too small.
There are two ways to answer this one… If once a micrometer is
put onto the tool, it really is found to be smaller than the crank,
then get some metal tape and press down the first 2-3mm of the end
onto the tool. For the remainder, coat the inside of the tape in
oil and pull the tape around so that you ultimately have a tool
which is at least the diameter of the crank and preferably 0.001-
0.002’’ greater diameter. Once done, as the tape is mostly not
secured to the tool, it’ll come off easily without scoring the
tool. A tool which is smaller than the crank does no useful work as
the seal will ultimately be sized on the crank. Contrary to Larry’s
speculation, the same tool is used for the v12 crank where the seal
sits very close to the rear main bearing as part of the rear main
bearing cap - this is why a Jaguar technical bulletin gives advice
about not heating up the bearing else warranty is voided. There is
no change in specification to the tool.
If the seal is sized on the crank, there is another bit of bad news
in that it’ll be spun over the oil groove. This will attempt to cut
into the rope surface rather than press the seal into the groove.
Keep in mind that the crankcase will almost always be under partial
vacuum and that the outside is at full atmospheric pressure. This
will tend to want to make oil be pulled back into the crankcase.
kind regards
Marek–
v12 E-type running MS3/3X sequential lpg and petrol
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