In response to all the comments about cranking a TR engine to free the
head.
I WAS WRONG! Although I remember hand-cranking the engine to free the
head on my TR2 back in the '60's, I can't remember if this was really
necessary every time (and I took the head off a number of times). I
agree with Will that the pistons don't touch the head (at least not
under normal conditions), and I think that it must have been the
pressure exerted by (some) of the pistons moving up.
After I read all the comments, I went home and dug out my dog-eared
Morgan Four Wheeler Workshop Manual (yellow cover) to see if it
mentioned anything on the topic. I quote (p.78) under a section
"Decarbonising - Valve Servicing"
"Dismantling procedure is as follows. The battery is disconnected and
the cooling system drained. The carburetor air cover is removed,
detaching from the crankcase ventilation pipe. The top water hosepipe
is disconnected and the by-pass on the thermostat, the thermometer bulb
being removed from the thermostat after unscrewing the gland nut. If
heater hoses are fitted, these are removed, then are disconnected the
carburetter controls, feed pipe, and the manifold drain pipe. Then
follows the sparking plug leads, and the rocker cover, the suction pipe
being detached. The exhaust pipe is disconnected.
The rocker shaft is loosened uniformly: easing the nuts, then removed
complete, to be followed by the spring retainers, springs and push rods
- these being maintained in proper order in compartments in a box or
placed in holes drilled in a board. The cylinder head nuts are removed,
then the head raised, with attention that the cylinder sleeves do not
lift. The engine should not be turned to assist in lifting the head, as
this may cause the sleeves to move. Inlet and exhaust manifold are
removed together from the head."
further on (p. 81)
"It is advisable to use a decarbonising set of gaskets, which will
include cylinder head, manifold, carburetter, exhaust pipe, etc."
So there you have it. This vindicates all those (Chip, Will, John &
Fred) who urged caution or strongly advised against cranking the engine.
Thanks, guys, for setting me straight. Greg, my apologies for leading
you astray; I hope Chip's cautionary note got to you in time.
My only (feeble) defense is that my work on the TR-2 preceded my
acquisition of my +4 (and the Morgan Shop Manual). I plan to, however,
work on the Standard engine in my +4 one of these days and without this
exchange of comments I might have done something stupid.
Thinking back now, I remember that the manual that came with my 1956 TR2
mentioned something about "decoking the engine" and I wonder if at that
time engines could have had carbon deposits at the head/block junction
that needed more than some coercion with a mallet to separate the head
from the block. Whether or not the sleeves would actually move would, I
would think, depend on the relative coefficient of friction between the
piston rings and the inner cylinder walls and that between the block and
the outer cylinder walls. Not knowing the magnitude of either, it would
be safer not to crank the engine.
Note to Dave McCoy:
Do you have a mechanism e.g. "editorial powers" to purge misinformation
from the collective writings of the Morgan Group? I'm not suggesting
you rewrite history (what I have written, I have written and I take
responsibility for that), but I'd hate to see somebody led astray.
Chuck
Chuck Vandergraaf
'52 +4, P.2473/V.345.ME
'87 Olds Custom Cruiser
'85 Chrysler LeBaron Turbo
Pinawa, Manitoba, R0E 1L0
Canada
vandergraaft@aecl.ca
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