Page 42 - Dec 2022

The Lat he, continued from page 41

and start (only start) the threads on each end.

I repaired to my garage and proceeded to use the old
South Bend to carefully finish cutting the threads on
each stud to snuggly fit the holes in the block. Strict
attention also had to be paid to the overall length of
each stud as they were ?captured? between the
?acorn? head nuts and the blind holes at the bottom
of the block.
Further , four of the long studs had to be a bit longer
than the rest to accommodate the engine lift fittings
which were installed under head nuts at four
locations ?details , details.

After completing this long, tedious, process I re-fitted
the various studs in the correct locations and
installed the head. Finally, using my own peculiar
procedure, I torqued it down and , voila, no leaks!

The St ripped Spark Plug Hole

The other project worthy of mention has to do with
the bane of all alloy cylinder heads ? the stripped
spark plug hole. Jaguar even anticipated this and in
their factory manuals they describe, and diagram,
fitting an insert to correct the problem. Trouble was,
to my knowledge, they never made any of these
inserts as repair parts.

Coils and thin steel inserts had all been tried and
failed. The fact that plugs are routinely removed and
replaced for a variety of reasons was just too much
for them. So , after studying the Jaguar diagrams I
decided to try and fabricate the type insert they were
talking about.
Back to the late of South Bend. Starting with a piece
of 1 inch diameter aluminum round stock I started
turning, boring, and threading. The finished product
(see photo) looked like it would do the job so I
proceeded to over bore and tap the offending plug
hole. The final step was to pin the insert in place--
Worked like a charm.
Above: "I decided to try and fabricate the
If nothing else this exercise makes you extremely
sensitive to the importance of a ?light? touch when type insert they were talking about."This is
installing plugs in alloy heads. my stripped spark plug hole repair bush
Petrol Powered fitting.

Performance, all the
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