Page 40 - Dec 2022
P. 40
The Lat he continued from page 39
Of the numerous parts I've made a few stand out.
Here's where the old lathe really earned its salt ? and
saved my Jag from an unknown fate.
If you're a regular reader of this newsletter you
probably saw the clip about my oil pressure mystery.
That was a story in itself. There are, in my biased
iStock image by Oksahna
opinion, a couple of others.
XXXXXXXXX
St uds? How Hard Could That Be?
The first of these was the fabrication of set of cylinder
head studs. A bit of background is needed here. These
studs are not your usual pieces of hardware. Oh, they
appear to be garden variety carbon steel but that is
where the similarity ends.
In one of the evolutionary changes to the famous
Jaguar XK engine, as used in the E-Type Jaguar, the
company increased the displacement from 3.8 to 4.2
liters. This in turn required a minor , but significant ,
repositioning of the cylinder bores.
Coolant passages had to be modified and this made it
necessary to move the anchorage of the head studs
from the upper deck to the lower part of the engine
block and on it went.
The end result was that only the two forward -most
and two rear-most studs remained near original
length (about 5 inches) and were anchored in the
deck. The remaining ten (10) studs were lengthened to
over 12 inches in order to reach from the top of the
cylinder head to the anchor points at the bottom of
the block. These studs had to pass through clearance
The singular minds behind holes in the deck and thereby allowed a pathway for
some of the engineering in coolant to reach right up to those nice , chrome, acorn
British sports cars were nuts at the top of the head.
apparently believers in wishful
Brit ish Engineering is Based on
thinking,
Providence
No gaskets or seals, just the metal to metal clamping
force was counted on to keep the coolant where it Leaving the rest of us to deal, 50 years later, with
belonged. A bit of wishful thinking. These long studs what they so casually wrought.
were only 7/16?s in. in diameter and as best as I could
40
