Two weeks ago, there was some discussion about the proper torque for the
nuts holding down the valve cover. This weekend, while putting in a new
valve cover gasket on my newly acquired 70 1600, I came across a problem
that suggests that an oil leak from the valve cover may not be due to
either a bad gasket or improperly torqued nuts.
With the old, leaky gasket off, I placed the bare valve cover back on
the head and noticed that it seemed to be riding too high along the back
of the engine--the gap was about 3/16ths of an inch, while the front of
the cover rested much closer to the top of the head--about
1/16th of an inch. The gap is created because the downside face of the
cover has small ribs or prongs around the perimeter, apparently designed
to create an even 1/16" gap all around, which is easily sealed with
gentle pressure on the thick cork gasket. (It also prevents one from
drawing down the nuts too tight, thus breaking the gasket.)
But what was causing mine to be riding too high along the back, a
problem which no doubt contributed to the leaky condition of the old
gasket? With a little tinkering, I found the culprit: Under the elbow
shaped vent pipe which runs to the air cleaner, there is a metal shield
which probably prevents oil from splashing into the pipe. Trouble was,
the hump on the shield was off about 1/8 inch, and was bumping into the
large nut holding the rear of the rocker assembly, thus keeping the
cover from settling to its proper level. (No evidence of tinkering by
the PO, so it might be a design flaw.)
The fix wasn't too difficult: Drill out the four aluminum rivets
holding the shield, put it in a vise and flatten the hump slightly with
a ball peen hammer. The shield goes back on easily with 1/8" aluminum
pop rivets, which can hardly be distinguished from the original.
I'm new to the list and don't know if the problem is mine alone, or
perhaps shared by others. If you're troubled by persistent oil leaks
from the valve cover, check this out before torturing yourself with
minute torquing tweaks or wasting money on a new gasket.
Bob Porter
Harrisburg PA
|