On 96-09-07 I wrote:
<< It was fogging mosquitoes like crazy, diagnosis is definitely very loose
valve guides. >>
Well, I was wrong, but definitely on the right track.
Upon further inspection we determined the head had been shaved 3/32", and the
shims under the rocker pedestals were to correct the resultant rocker
geometry. These shims are in fact listed in the Moss catalog for use with a
shaved head. The flat top pistons are strictly standard fare as well as
stardard size (not .100 over). Thank you all very much for the wisdom of the
net.
When we removed the valve springs, the guides were in particularly good
condition, like the rest of the engine. A machinist from a local engine shop
verified the good fitness of the guides. But what we found instead was some
improper assembly of the valve spring parts.
There is an oil deflector within the top of the inner valve spring. Five out
of the eight deflectors were installed at the bottom of the springs instead
of at the top, like the inner springs were put in upside down. The deflector
was then sitting on the base cup (or collar) and did not seat all the way
down to the flat surface as the spring should. It was held up about 1/16" by
the inner shoulder of the collar that should center the inner spring. In
that position the deflector is tall enough to extend up just above the top of
the valve guide, and is closed at the bottom by contact with the base cup.
With the engine running, the deflector would fill up with oil until the oil
level was just over the top of the valve guide. Copious amounts of oil would
then run down the inside of the guides into the cylinders, even being sucked
past the intake valves by the intake vacuum. The deflectors for #1 cylinder
were in the correct position, and that cylinder had only a little oil in it,
which probably got there by way of sharing the intake port with the next
cylinder. All the other cylinders were loaded with oil.
We don't have the head back on yet, but I think that correct reassembly is
all that's required to stop the mosquito fogging. Me thinks the DPO must
have been drunk when refitting the valves to his newly shaved high
compression head.
Barney Gaylord -- 1958 MGA
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