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My CQ engine swap project continues it's glacial pace.
The engine is up on a stand in the basement, and I've busied myself by studying
the function of the smaller bits before removing them. My intention has
been to rebuild the engine before beginning the actual swap. It's got 102K
miles on it, and while I know these engines do well long beyond this point, as
long as I'm going to the trouble and expense of doing the swap, I figured it
might as well be with a fresh engine.
Anyway, last weekend, I finally got around
to doing a compression test, and am disconcerted by the results: Bentley
says factory fresh normal is 131-189 or 9-13 bar, with an acceptable variance of
44psi/3bar between cylinders. My results were as follows:
Cyl range
psi
1
185-187
2
179-190
3
179-194
4
185-186
5
155
Since I rigged this up with a battery on the basement floor,
jumping the solonoid switch with a screwdriver, my cranking was a little
erratic, and generally I feel that the higher numbers are more accurate.
In any event, I'm now wondering about the wisdom of re-building the engine, and
I'd be interested in your collective input.
Should I skip the rebuild and just replace expendables like
hoses, water pump, oil seals etc.? Should I just do valve seals, seats and
a grind? Go ahead and replace rings, bearings?
I've been assuming that eventually I'll want to do HP
upgrades, and so have half-planned to get a performance head gasket, raceware
bolts etc., so maybe that consideration alone argues for a complete
teardown.
Finally, what do you think of those compression numbers?
My mechanical background is somewhat dated, and heaviliy concentrated in the
area of British sportscars. The apparent low wear of cylinders, rings, and
valve seals is completely beyond my experience. It's fascinating to me
that an engine with this life would have compression specs within the factory
range, although weird that two cylinders would be _higher_ than new... I
also think this car had less than optimal service, the timing belt for example
looks awful (cracked and hard) and must be original. The plugs all look
pretty sooty, but then again the last time the engine was run was 3 minutes for
my benefit just before being yanked out of the tq, so I'm reluctant to draw any
conclusions from their condition.
Thanks for your opinion,
Brandon Hull
'91 CQ and a shrinking 3B...
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