Wow, this is a very timely thread. I was just discusing these differences
with someone today. Perhaps someone with a disassmbled MB/GPW block can
help...
According to the manual (civilian) the nose of the crankshaft on those
engines equipped with a chain and sprocket (not gear..) are oiled thru 4
holes in the sprocket itself. There is an annular groove on the bore of the
sprocket, and the nose of the crankshaft has a thru hole drilled at 90
degrees to the keyway (which is at the 3:00 position when at #1 TDC). This
cross hole is fed by the front main.
Can anyone confirm if there is in fact a plug at the 11:00 position where a
'gear' equipped engine would have this hex shaped nozzle? Is there a hole in
the engine mounting plate around it?
Secondly, since the chain means that the Camshaft and crankshaft turn in the
SAME direction, but with a gear the camshaft and crankshaft turn in the
OPPOSITE direction, I assume this means a totally different cam so exhaust
doesn't open before intake? And since the camshaft drives the oil pump, I
assume the pump is set up for reverse rotation?
Did they use the same cam and reverse the rotation of the engine and firing
order? I assume NOT!
Would this mean that the flat bottom pump comes on gear equipped engines and
the pump with the bump on the bottom is for the sprocket and chain. Or was it
a bump on the left vs a bump on the right?
I seem to recall that the oil pump bore in the block was slightly larger on
MB so the MB pump couldn't mistakenly be inserted in the wrong block?
Am I imagining all this?
The chain and sprocket was MB and CJ2A thru Serial number CJ-2A 44417 (engine
number) motors after this started with a "J" prefix
The much later manuals state that a new timing gear oil jet entered
production with engine serial number 3J-166871 The earlier jet has a .070
diameter aperature, the later has .040 inch. It goes on to tell you if ther
is evidence on older engines of oil starvation to #1 rod, retro fit the
smallet jet.
This archive was generated by hypermail 2b29 : Tue Jan 02 2001 - 23:13:23 PST