So last night I got around to using the miniature wire brush to clean
some of the crud out of the combustion chambers and off the valve faces
of The Green Car's cylinder head. I had noticed that the exhaust valves
had receded a noticeable amount, but I was still surprised when I got to
the #1 chamber and saw that the exhaust valve there was actually lower
(well, higher, but you get the picture) than the combustion chamber face.
That answered my question about what I could be expected to do with it.
Combined with my lack of success with the valve spring compressor (I
got the kind that is supposed to work with the head on the car, and
it doesn't want to work with the head off the car), I decided last
night to call my machine shop and get a quote on a valve job.
They'll put in new seats, grind the valves, resurface the head, and
install my new guides for just over $200, and it'll take about a week.
Sigh, again. Now I've got to call O'Connor and see about the rest of
my gaskets. At least I can get the block in shape over the weekend so
that when the head is done I can drop it on right away.
BTW, I recommend a wire brush on a Dremel for a lot of engine cleanup
work. It doesn't remove any metal, and it's not even great on really
bad deposits, but it's terrific at cleaning surface gunk off the outside
of the head, removing baked-on crud from the combustion chambers, and
the like. It's a fine decoking tool, because the wire is too thin a
gauge to do any damage to cast iron but the tool turns fast enough to
do a halfway decent job. It'd be a great tool for getting the soot
out of exhaust ports, for example.
Oh, and I'll also grind out the exhaust manifold to help get the step
you want going from the port into the header. That helps avoid reversion
of exhaust gases, which keeps each cylinder's worth of intake charge
that much cleaner. Don't know how much of this is going to matter to
the original bottom end, but it can't hurt. I'll do the rings and
bearings next year.
BTW, anyone who followed the Don Roberts railroading at last year's Solo
Nationals might be interested to know that I've solved the problem of
valves and springs on 1971 MGBs. Yes, it IS in the book, and yes, it
IS only a limited number of 1971 MGBs that come with big valves and
double springs. I've got one. The trick is that it has to be a
car number after 258xxx but before they started putting in the 18V
engines. My B is number 262144 and has an 18GK engine; the head has
a February 1971 casting date on it and appeared never to have been
removed from the car. (Sam, you might need to know those numbers for
IT too, come to think of it; it's in the Bentley manual.)
--Scott
|