Allen -
If the low reading you have in #3 indicates a scratch
in the cylinder wall, this is nothing really to worry
about.
If the cylinder wall is scratched, compression will
only be low at very low RPMs (actually at 124# for a
static test, you may not even have a problem here).
What I'm saying is as the engine revs up, compression
will return to normal parameters and you shouldn't
have any loss of power, fuel efficiency or smooth
running. The only people that might have an issue is
California EPA when they detect excess hydrocarbons
coming out the tailpipe at idle... but if you don't
have to deal with a smog test, then it won't matter!
The other thing to keep an eye on is the cleanliness
of your oil. With a scratch on your cylinder wall,
you can get a little combustion blow by into the
crankcase (at 124# it should be very little), which
shouldn't be cause for major concern except your oil
may get dirtier & acidified faster than normal. If
you have a spin on filter and change the filter & oil
when it starts turning black, you'll be ok.
Frankly, if you keep it all in good shape, you can
easily get tens of thousands of more miles out of the
engine....
Cheers,
Alan
'53 BN1 '64 BJ8
--- "Allen C Miller, Jr." <acmiller@mhcable.com>
wrote:
> I was fortunate to get a brass freeze plug from
> David Nock in Stockton to
> replace the one that blew off. The brass goes in
> very easily and seats well
> with a slight ponk to the middle. Very much
> recommended. I hope you BN less
> than 4's benefit from my mistake. I knew a 4#
> radiator cap was required, but
> when I wasn't looking, the restorer put in a 7#,
> which never let off.
> Fortunately, the radiator was freshly re-cored, and
> did not wipe out. The weak
> spot was a freeze plug behind the coil.
>
> Another new item available from David is the
> original BSF stud that holds the
> generator plate down vs using 5/16 BSF bolts. Went
> in cleanly.
>
> It was good to hear the M roar again. I thought I
> had cooked it. I am running
> a little low on the inner two compressions (144 #4
> 124#3 134#2 148#1, but
> hopefully that is not too bad. I know from the head
> rebuild that #3's low
> reading is due to a small scratch in the wall which
> I am deferring to a more
> comprehensive rebuild. Any thoughts if this is too
> much a variance?
>
> I also have been putting off the re-torquing, but
> maybe need to now (1000
> miles on the head rebuild). Do you let back on the
> torque before you reset, or
> do you just tighten in the proper pattern?
>
> Allen Miller
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