I was hoping some one more knowledgeable than me would take on all of your
questions. So far, you have done well in investigating and asking the right
questions. The only problem I see is that the compression on one cylinder
indicated a problem. While the head was on, you could have investigated it
further, by poring a teaspoon full of oil into the cylinder and then seeing
if the compression increased. That would tell you if the lower compression
was related to the rings or not.
But on your questions -
#1. The brown/dry was the one normal cylinder although the blackness of the
others could be due to a number of causes.
#2. Reuse of the studs was a controversial topic on this list a year or two
ago with some saying the studs should always be replaced. I certainly
wouldn't use two nuts. But I have to admit that I have never replaced the
studs before although I am doing it on my current (3rd) rebuild. This is
mainly because I do have a few studs like you described where the nuts were
frozen to the studs. Plus the cost of replacement studs are not that great
- just a few dollars apiece.
#3. I have never used sealant on a head gasket and I am fairly sure this
should not be done. Just a gasket on two clean surfaces (the head being
machined smooth). However, it has been suggested by noted MG guru John
Twist that placing a small copper wire along one side (spark plug side) of
the head gasket will prevent the possibility of weeping (very small leak)
from the head on that side. The archives may have more on that. I have
never done this nor have I ever had this weeping problem. There may be
details also at John Twist's site (www.universitymotorsltd.com)
#4. This question can really only be answered with a question - how much do
you have to spend? Most of my MG driving days were days of poverty
(relatively speaking) so I had to compromise between budget and doing it
right. Since the head is already out, it would be prudent to spend the
money to have a machine shop do a valve job which may possibly involve a
valve grind/ new seats. And certainly get the head surfaced. The motor is a
different matter - if the cylinders look okay and the ridge is only slight
and oil pressure was good, you can always postpone the engine for another
day. Your white smoke should be gone and hopefully you will get your
compression back on the low cylinder. Some people do replace rings and
bearings with the engine in the car, but I would rather do a complete
engine overhaul with the engine out if I was going to do rings/bearings.
#5. The shims have also been discussed on the list as to why they are
there. I don't recall the actual purpose. The head I just took off my car
that had 120-130k on the engine and about 140-150k on the valves did not
have the shims (maybe they were never there or I lost them when I had the
valve job done in '81). But the replacement head has them. I'd put them in
just because the shims should be very cheap and its how it was designed
(oil flow?).
I'm not a professional mechanic by any means but I did help out a mechanic
one year so I could use his shop and his expertise for engine overhaul #2.
He claimed he was a certified British Leyland mechanic, but I was later to
have doubts on that. But he did teach me much on the right way of doing
things as opposed to cobbing things together. It has served me well.
David Councill
67 BGT
72 B restoration - proceeding and hopefully on the road by August
At 03:39 PM 6/16/2002 -0400, Chris Chandler wrote:
>All of which leads me to a series of questions.
>
>1) With regards to the cylinder head picture, I would assume that the
>different look of the cylinders (#4 being brown/dry) and the rest being
>different states of oily points to something being wrong. What?
>
>2) In case you didn't notice in the cylinder pic, a couple of the studs
>came out with the nuts instead of staying in the engine. Should I get
>all new studs & nuts, or re-use the old ones? When putting the old ones
>back in (or new ones for that matter) do you just use two nuts, one
>acting as a jam nut?
>
>3) When putting the new head gasket on, is there any kind of
>glue/sealant that should be used, or just put it on there and put the
>head on top of it and torque everything down properly?.
>
>4) Is there anything else I should have done while the motor is this far
>apart (without taking out the motor)? Valves ground? New seats? Head
>surfaced?
>
>5) the book mentioned shims under the center posts on the rocker
>assembly. Mine did not have any (it appears to be a '67 or '68 engine).
>The book seems to imply that even if it didn't, when I put it back
>together I should put some in. True?
>
>I'm sure there will be more questions, but these are the ones that occur
>to me most immediately.
>
>Thanks for any help.
>
>Chris
>70 B Roadster
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