Wille R. wrote:
They came with a minimum at 1.500mm from factory. You may regrind them using a
fine sand paper but it's not the best way. If you try cut the top of the valve,
don't do it. there is sodium inside.
1. Only the exhaust valve stems are hollow and contain metallic sodium.
2. If you had ever seen a drawing of a sodium filled valve, you would
know that the hollow part of the stem (and the sodium) does not extend
into the top third of the length of the valve stem--so this is a
non-issue for this operation.
There ARE two problems with 'tipping' the upper end of the valve stems:
First--the case is much harder than the interior of the stem--if you
remove too much material, and go through the case hardness, the tip of
the stem may tend to 'mushroom', and create a LOT of pretty obvious
problems.
Second--the surface of the end of the valve stem must be absolutely
SQUARE to the length of the stem when the job is complete. So--this
operation is NOT something which ought to be attempted with any sort of
hand tool !!
Being the contrary sort--I once took a sodium filled exhaust valve
(taken from a Chrysler 413 truck engine), put it in a vise, and cut the
stem in two using a 9" angle grinder. Wore a leather welding jacket and
gloves, and a face shield, 'just in case'. "pfffftt" (lower case
intended) was all that happened, as the sodium inside the valve turned
into sort of a yellowish colored lump. I'm still here more than a couple
of decades later.
Greg
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