D2, I hate to disagree but... while it's difficult to
do a hone job in the car, it's not THAT difficult
UNLESS the crossmember is in such a place as you are
unable to get to the rod bolts. I expect many of the
grey haired (or no haired) IMLers have done this as it
used to be a fairly typical shadetree approach. More
modern cars with all the 'stuff' on them makes it more
difficult.
I've done this at least 3 times, once outside on a
gravel driveway, once on concrete carport, and once
inside with the lift. You can guess which was easiest
but then I was once younger and the gravel did not
seem that bad at the time. Two people makes it easier
also but it's not really much more difficult than
building the bottom end like I did on the 73
With the heads off, if the bores are still 'round' as
checked with a dial guage and the ring ridge is not
excessive, the motor is a good candidate for a hone
and re-ring job. Compression tests alone will not
tell you everything you need to know because oil
consumption is more determined by the state of the oil
rings which can wear at different rates.
It is also fairly common for a decent running engine
to suffer as a result of a valve job. As previously
mentioned, increased compression puts a strain on
things previously Ok. I had this happen to a 56
Chevy. It ran good, no smoke except at startup.
Brilliant teenager that I was, I decided it needed the
heads done. After that it smoked like a chimney.
While on the subject of shadetree engine rebuilds, the
main problem with this entire approach is the cam
bearings. You can pretty much rebuild everything in
the engine while in the car EXCEPT the cam bearings.
(I suppose they COULD be done in the car but I've
never known it to be so) Low oil pressure is
frequently the result of worn cam bearings. Just last
summer, the oil pressure in my 87 Ch*** PU got low and
when I pulled the pan I discovered main bearings and
rod bearings pretty well worn to copper. Replacing
them (in the car) helped but the oil pressure did not
come back up where it had been and I expect that the
cam bearings are worn out also. On the other side of
that coin, when I replaced the bearings in the 73 IMP
there was a noticable improvment in oil pressure. I
suspect this is because the 73 was not worn out.
I don't have an advanced degree in automotive
engineering to explain WHY these things happen but do
have the skinned knuckles and eyeballs to observe what
has happened in the past.
Kerryp
--- "D. Dardalis" <dardal@xxxxxxxxxxxxxxx> wrote:
> At 06:02 AM 6/17/2002 -0700, you wrote:
>
> > > David, you can't replace rings without removing
> the
> > > engine from the car, as far as I know.
> >
> >Never say 'can't' to an engineer!
>
> OK, I withdraw the "can't" and replace it with "very
> tough, so tough that
> it may not be worthwhile"! How is that Mike?
>
> >Putting that fresh head on an old short block will
> >cause more oil leakage and blowby in the bottom
> end.
> >Best to do a ring and piston job if you're doing
> the
> >heads.
> Mike, if the rings and bores are still within specs,
> they should be able to
> handle the compression. Its quite common for the
> heads to "wear out" while
> the bottom end of the engine is still serviceable.
> WHether the bottom end
> is still serviceable can be determined by a
> compression test. And David,
> there were some suggestions to confirm/ensure you
> indeed have a head gasket
> problem before you start removing the heads. I also
> agree with those
> suggestions.
> D^2
>
>
>
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