Now that I got the head off my 77 Midget (1500cc) I have more than a
few questions about what I am seeing. Just a recap, I took the head
off because I had very low compress cylinders 2 & 3 (something like
40 & 60 psi dry) and about 120 psi dry in 1 & 4. I also had high
crankcase pressure. Oil was coming out the dipstick hole. I was hoping
it was a blown head gasket between 2&3 and one of the oil galleys.
Looking at the head gasket it does not look like there is a problem
there. I don't see anything obvious (not that I am sure what I should
be looking for). The color of the gasket is the same i.e. no black
traces or worn looking areas.
Other things I am seeing. If you into the cylinder head where the
intake and exhaust manifold attach you see the following; dry soot
on the exhaust, and black oily deposits (sort of like oily carbon)
on all of the intake ports. These deposits are rather lumpy, you can
rub them off with your finger. What would this be? Worn valves guides,
rich carb, maybe?
The combustion chamber on the cylinder head looks ok. Not very much
in the way of deposits. The valves themselves are black, with some
of the exhaust valves being gray at the center. I guess they get
hotter?
The tops of the pistons show the following. 1,2, & 3 have quite a bit
of hard black deposits on them. I cannot see any of the original piston
top. Number 4 has much less and I can see most of the piston top.
I am trying to decide how I should proceed. I could just put a new
head gasket, put most of it back together and see if I get any
different compression figures. This would be the cheapest way. What
are the other logical routes to take? The closest I have come to
rebuilding engines is the 2 cycle dirt bike I had as a kid. That was
quite a bit different.
If it looks like a rebuild, where should I look for some helpful
information? I mean what is required, what machine shop services
would I need, boring cylinders, fittings cams, checking cranks and
rods, etc.? What can I do myself, what should I check and re-check?
Two other beginners questions. 1) what is magnafluxing (sp?) 2) what is
shot peaning (sp?). I have seen both of these terms used when
discussing whether a part can be reused.
Looks like I might have bit off more than I wanted for this winter.
Oh well. Sorry for all of the questions, but this area is completely
new to me, and I am not even sure what I should be seeing. Thanks
for any advice.
Bill Gilroy
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77 Midget (got it for free, and final cost still not in)
90 Shar-Pei (got him for free, and over priced at that)
No cats
PS. Happy Thanksgiving for all the people in the states, and the rest
of you have a nice day.
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