I can't speak for the MGA, and I know early MGB engines were different, but
from November 67 the situation is as I described - you have to tighten the
rocker cover nuts down to the shoulder on the cylinder head studs to get any
pressure at all on the cork gasket. With rubber washers and cork gasket
having been on my 73 engine a year or so, there is only one turn of the nut
available between taking up the free play, and bottoming out. It is only this
one turn of the nut that applies pressure to the rubber washer, rocker cover
and cork gasket, which is going to be a million miles away from damaging the
cover. It *should* be more than one turn with a new cork gasket and rubber
washer, but in my experience it isn't much more. Certainly if you continued
to tighten the rocker cover nuts after they had bottomed out you would
eventually strip the threads or snap the stud, but you won't be applying any
more pressure to the rocker cover or cork gasket. I have put together some
pictures at http://www.mgb-stuff.org.uk/rockercover.htm showing the nut with
and without the cup washer and rubber washer showing how much clearance
remains if the spacer is not present. And if *any* of the cup washer, rubber
washer or spacer are omitted you won't get any pressure on the cover at all
and it will be rattling around. As I say, MGA and early MGB may well be
different.
PaulH.
----- Original Message -----
I didn't see anyone step up to correct this, so I guess it's my turn. Do
NOT tighten the valve cover nuts down to any mechanical stop, as you risk
bending the valve cover and breaking one or more rocker pedestals....
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