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TD Rebuild Saga

To: MG T Digest <mg-t@autox.team.net>
Subject: TD Rebuild Saga
From: Stuart Keen <simbafish@home.com>
Date: Fri, 13 Apr 2001 18:48:35 -0400
I want to thank one and all for their support, their patience and for
sharing their knowledge during the "overhaul" of my 51 MGTD MkII. I
could NEVER have accomplished what I did without your help and
encouragement. I know Murphy is looking over my shoulder, but I will be
so bold as to say that for the moment, I have come to completion. I
know, the car will be 50 years old this October 10th, so I must expect
things to go wrong, but I am trusting I can get some pleasure out of it
and distance myself from automotive mechanics for a while. It has been a
long haul, indeed!

But I will be the first to say that this project nearly overwhelmed me.
It was like climbing Mt Kilimanjaro in 1996. The summit was within sight
but it seemed impossible to reach. However, in both cases I was not to
be denied success, though depression truly set in at times.

I set out to solve a high, 175 mile per qt, oil consumption problem.
Since the XPAG had been rebuilt (new crank, pistons, rings) just one
year, 11000 miles ago, it was believed that only the valve guides and
seals had to be replaced. That is ALL that I set out to do. A relatively
small project. How naive of me.

I found seven of the eight valves were badly recessed. Since this is a
MkII with already enlarged valves, putting in even larger valves was not
an option. No machine shop locally would venture to put in hardened
seats. Finally I found a machine shop 75 miles away that frequently
works on XPAG engines. They did an excellent job. The head came back
looking NEW (at a cost of $468!). Magnafluxed, acid bath, painted, new
valves, guides, modern positive seals, hardened seats, etc. 

The machinist said there was no way I could lose that much oil via worn
valve guides and seals. Since the guides stick ABOVE the surface of the
head, the head would have to be flooded with oil. And even then, there
are enough passageways back to the sump that little would make it down
the guides. He looked at my pistons and said there was clear evidence
that my problem was "fuel flushing", running the SUs too rich, excess
fuel diluting the oil, losing the lubricating properties and thus the
cylinder walls becoming prematurely glazed. The result was that the
rings were no longer seating. So HIGH OIL CONSUMPTION.

So now I was faced with taking out the pistons, out the bottom, pass the
crank. Lots of fun while laying on my back. Then I wrapped the crank
with tape, plastic, and basically cocooned it. Then honed the cylinders,
cleaned, washed, and put the pistons and new rings back in. So far, so good.

When I took the rocker assembly off the head, one push rod was bent and
one rocker support was broken in half. Ordered replacements. The new
rocker arm support was drilled/milled about 5 degrees off center.
Another set back. No new ones available so opted for a used one. It is
actually better than the other three installed.

Then I put on the end plate to the head. After it was installed with
gasket, I noticed what looked like a small pin hole. Never lost water
before, so checked with a piece of AWG 22 wire. It went in ONE FOOT.
Guess there had been a scab of rust on the inside that kept it sealed,
but could have blown any time. A new end plate was ordered. More delay.

Then I assembled it all. I had also purchased a new thermostat and
housing as mine had been stripped of its thermostat by an earlier
garage. When I later fired up the TD, I found to my horror that
water/antifreeze was weeping through imperfections in the new casting.
So yes, I was faced with yet another set back. I installed the old
housing to get the car on the road.

My carburetors had been professionally rebuilt. Tried to tune them, but
the rear could NOT be made lean. After two hours of frustration, I
limped to a local Brit garage. He thought it was going to be a 5 minute
job. An hour and a half later he discovered that the rebuilder had put
the wrong jet in the rear SU. It was so large that the needle could just
rattled around in it; just no way to cut off the flow of fuel. To get me
home, he dug out of a trash barrel a worn jet from a TF. The rebuilder,
to his credit, sent me a new jet and paid the bill for the work at the
Brit garage.

Then I had the front right Girling damper rebuilt. It leaked like a
sieve. When it arrived on Saturday, I wanted to check, according to the
manual, that the fluid was at the right level. I tried with vise,
wrenches, hammers to unscrew the filler cap. Would not budge. So I had
to wait until Monday when the office would be open. I called the
rebuilder and learned that he had "sealed for life" the Girling. Nice
that there was no note in the package stating this.

More delay. And then for a whole week I got a bad case of food poisoning
from a local seafood restaurant; so I lost more time. I was beginning to
feel I and my TD were jinxed!

Finally last week, almost two months after I set out to solve an oil
consumption problem, I got the TD on the road. Then last weekend I drove
it with the Suncoast British Car Club
(http://clubs.hemmings.com/suncoastbritish/events.html ) to a car show
in Orlando (2nd place). Went onto Cypress Gardens. Total mileage about
450. No rods came out the side, no strange noises, so I am trusting that
I followed advice correctly and all my work was done well. I expect the
TD to perform for the next 80,000 miles without mishap. 

My oil consumption, if extrapolated, is down to about a qt in 3000 miles
or LESS. My fuel consumption has gone from 19 mpg to 27 mpg. All good
signs for a long life. Since the car is still in its "shake down phase",
only time will tell how well these consumptions will hold.

My thanks again to all of you who showed sincere concern, advised this
layman and contributed your vast knowledge. You can take the credit for
a "job well done". It could never have been done otherwise.

Stu Keen
51 MGTD MkII

Venice, FL

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