Hi list,
I've recently reconditioned the head on my '69 Midget (1275) and want to
check the compression. I have bought a compression tester, but have been
given conflicting advice on how to carry out the test. Is it better to
test by removing one plug and firing up the engine (on three cylinders) for
a couple of seconds, test with three plugs in but only using the starter
motor to turn the engine, or to remove all plugs and test each cylinder
using the starter motor only ?
I have tried methods one and two above (both wet and dry tests) and the
results vary greatly depending on whether the test is conducted with the
engine running (cyl 1 = 85 psi, 2 = 90 psi, 3 = 85 psi, 4 = 90 psi) or with
plugs in and using the starter motor to turn the engine (cyl 1 = 150 psi, 2
= 150 psi, 3 = 150 psi, 4 = 145 psi).
My questions are:
1. Is there a correct method?
2. What readings should I be looking for?
3. Regardless of the readings, why is there such a difference between the
two methods outlined above.
Many thanks in advance
Bruce Sch.....
Sydney Australia
'69 Midget YGN41163
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