Morris Minor Owners Club

Ed if you are worried about how true the head is do you know how to check it ?
If not it can be done with an engineers rule if you now how to use one properly or the good old fasioned way, get a piece of glass and smear it lightly witth engineers blue and then run the head over the glass if there are any defects they will show up as areas that have not been spotted by the blue, dont expect total covereage but just an even covering, if the covering is not even you will need to have it skimmed and under no circumstances should a head on an `A` series have anything but a head gasket no jointing compound is required, just ask your local engine rebuilders, if you are not sure who to ask locally try a mini specialist, you must have one of those.

I repeat, you should NOT use any gasket goo on a head gasket.
You should NEVER refit a head without a NEW gasket,and on the
Minor you MUST retighten the head nuts,,in the correct sequence,
within about 500 miles. Kevins' 'Glass check' should have read
PLATE GLASS, it is dead flat. I spent many a happy hour
in my Austin seven days flattening the heads by rotating them
on a sheet of plate glass on a mixture of parrafin and grinding
paste!

Thank you all for your valuable comments.
We managed to get the old by pass stub out and cleaned up the thread, with a neighbour's help. Then screwed a new one in with plumbers tape.
Well, we just put the head back on - with no gasket goo - but we used some on the thermostat and the heater housing. Ran it for a few minutes - and no leaks!! So far so good. It's running a bit unevenly, but we didn't check the valve clearances, so maybe we'd better do that next.
Then we'll have a run to make sure.
Great sense of achievement here - many thanks everyone, its been fascinating, and very helpful.

Ed how did you get the old stub out as I am sure this is a problem others will suffer from

Hi Kevin - good point, here is what we did.

We started by taking out the radiator (having drained the coolant of course) and removing the front panel in the hope that enough access would be allowed to remove the remains of the pipe.
However, what was left of the pipe was so thin that even a gentle attempt to turn it was enough to snap it off. Some people may be lucky enough to be able to simply unscrew the old pipe here, this was not so in our case. This left about 2mm protruding from the head.

We removed the head and got it on the bench thus allowing better access to the stub. With the help of a neighbour, we chipped off the protruding remains, which left the threads inside the head. These were basically cleaned out using a small hammer, and a small and fairly blunt screwdriver.

Starting at the top of the thread, it was a case of working around the threads, trying to get the remains of the old pipe out in as few pieces as possible, not least so less fell into the head.
I suppose we were reasonably lucky in that the threads cleaned up fairly well, but patience was the key.

At this point we carefully cleaned out the head using some small brushes to remove any shards of alloy/metal that had fallen in, but also flushed the whole system later.

We used a bit of plumbers tape around the thread of the new pipe to help seal it, and screwed it back in using some large pliers so as not to risk snapping the top off with a screwdriver.

So far all seems well, there are no leaks, and the engine runs fine (having adjusted the valves correctly )

Cheers