The Quietest MG

 

by John Stone

When I show my TC I like to start it for MG owners and watch their expression as
they listen to the engine.  "It doesn't sound like an MG" is the usual response.
.....and it doesn't ...... but more importantly why?

"What did you do to make it so quiet?" is usually the next question.  I really
don't know but I suspect there are a number of reasons, luck being one of them.
Let me tell you some of the things that may have contributed to the "quietest
MG".

When I rebuilt my engine the first thing I found out was that it had been
sleeved and had standard pistons.  Since the bores were in good shape all that
was needed was a hone to clean them up.  No real work here.  The second thing I
found out was that the crank was cracked beyond repair so a new crank was
ordered and everything was balanced before I assembled the engine.  Now it was
completely stock..bearings and pistons.  Everything seemed to have a nice smooth
tight fit.

The cam and tappets were also trash and had to be replaced.  When I asked my
parts supplier, Skip Kelsey, Shadetree Motors, about a cam he suggested a
reground (#673) that is set to .012" instead of the .019".  This is where I know
I have saved some noise but TF's are also set at .012" and they aren't
especially quiet.

When I asked Skip, who incidentally has a wealth of knowledge about MG's and is
willing to spend time answering questions, if I should replace my timing chain
he said "By all means. "It's the cheapest part in the engine and will make it
run quieter."  While installing the timing chain I found that the oil hold in
the tensioner had been improperly drilled and was in fact a blind hole not
allowing any oil to reach the foot which rides on the chain.  I found this
because Mike Sherrell's "TC's Forever" recommended checking to make sure the
hole was free of dirt.  While working with the tensioner I also installed a
leather washer under the spring next to the foot (also a "TC's Forever"
recommendation. Now the timing chain was nice and tight and the tensioner
quieted with oil and leather resulting in more noise savings.

Now to the upper end.  Most of the noise seems to emanate from the rocker cover
and I don't think its all rocker clearance.  My rocker shaft was quite worn as
were the rocker bushings and needed replacement.  That's not as easy as it
sounds....at least the way I went about it.  I pressed out the old bushings and
pressed in the new and then using an adjustable reamer, mounted in a drill
press, with B grade abrasive paste I carefully fitted each bushing to the shaft
with a fairly tight fit.  This took considerable time because each time I tried
the rocker on the shaft I had to clean off the paste and reapply it to ream some
more.  The results were very snug fitting rockers with little room for noise. I
suspect this greatly reduced the normally noisy XPAG.

The oil pump received new shaft gears but I suspect with all the oil around not
much noise comes from this area.  Next I rebushed the distributor. I pressed in
new bushings and used the same method as I used on the rockers to refit the
shaft.  Now it rotates smoothly and quietly.

Two other parts to be considered are the water pump, which received new
bearings, and the generator, which I left alone.

Also engine noise results from the intake and exhaust of the engine.  My engine
has an original air cleaner and a stainless steel exhaust system supplied by
Moss.  I think the Moss system is a little quieter than the original that I
remember from my first TC forty years ago but not overly so.

When I started the car for the very first time it was amazing how quiet it was
and how smoothly it ran. Now the engine has over 9000 miles on it and it's still
the quietest MG around.  While showing my car at Elkhart in July I learned a new
trick.  Rubbing chalk on the fan belt eliminates the fan belt squeak.  Now you
can't hear it run!