Engine Compression after Build

Richard A. Haney Jr. rahjr at cox.net
Wed Apr 28 22:13:16 CDT 2004

Been a list subscriber for a number of years.  Thanks to all for valuable
information throughout the years.

Bought my 1992 SE-R new.  Has all the usual bolt on performance parts.
Shortly after JWT S4 cams and ECU upgrade were installed, the car was
stolen.  Fortunately, the car was recovered about 2.5 weeks later.  It had
been well used.  New Metalmaster street pads were down by 70% and the clutch
(fried) and flywheel had gotten so hot all metal parts turned purple.  As
part of the shop diligence in assessing troubles, a compression check was
performed.  The results follow:  Dry Compression Test yielded Cylinder #1 =
150 lbs; #2 = 160 lbs; #3 = 115 lbs;  #4 = 160 lbs.

Decided to take the engine to a performance engine builder.  Bored/honed,
installed 10:1 Swain-coated .20 over pistons, appropriate rings, new
bearings, oil pump, timing chain and associated parts, blueprint and
balance, port and polish head and intake manifold, resurface block and head.
He conducted pressure test on the head, which was tight.

After putting some 1500 miles on the engine, another series of tests were
performed with the following results:  Dry Compression Test yielded Cylinder
#1 = 135 lbs; #2 = 150 lbs; #3 = 115 lbs; #4 = 150 lbs; Wet Compression Test
yielded Cylinder #1 = 150 lbs; #2 = 155 lbs; #3 = 140 lbs; #4 = 155 lbs; and
Leak Down Test yielded Cylinder #1 = 5% to crankcase; #2 = 2% to crankcase;
#3 = 5% to crankcase; #4 = 2% to crankcase.

Took the car to the builder, who did his own dry compression test with
similar results.  Hes ready to do what is necessary to make things right,
but we dont know what needs fixing.  All his measurements before the engine
left the shop, he says, were on specification and suggested a very tight
engine.  No oil burning is observed, but its been changed at 100 miles and
at 1,000 miles.  I followed all instructions about limiting rpms and oil
specification and change during break in.

Any suggestions about what ails the engine and possible fixes will be
greatly appreciated.

Dick Haney

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