OK here's the tale of the compression gauge so to speak. I ran a compression
test on the 1275 I purchased and here are the results. These numbers were taken
with a cold engine, sitting on a dolly, and I'm sure operating temps do make a
difference. Battery was fully charged and carbs were manually opened.
P.O. reported that engine all of a sudden started using oil after an extended
trip. One quart per 100 miles. Plugs are oil soaked and covered with heavy ash
deposits so oil is obviously getting in there someplace. I did notice that this
1969 vintage 1275 does have a buggered up(American version of buggered) vented
oil filler cap and does not seal properly. Emission gear has been removed and
air injection ports plugged. Crankcase is vented from flame arrestor and goes
up with one hose to a Y connector that goes into the carbs. No carbon
cannister, no vented return line to the fuel tank etc.
Engine has been sitting for an extended time and I cranked it over for perhaps
30 seconds before I started the compression test to try and circulate some oil.
Dry Wet
#1 130 lbs 175 lbs
#2 125 lbs 160 lbs
#3 110 lbs 135 lbs
#4 115 lbs 135 lbs
Battery did seem to be cranking slower for tests of # 3 & # 4 Cylinders so the
numbers could be off slightly. Lets give it the benefit of the doubt.
I'm not sure what the correct compression numbers are but I'll guess they are
on the low scale.
Your guesses on oil consumption from ring leakage, valves due to heavy oil
blowby.
P.O. Says no real visible blue smoke but I don't believe that line.
Is it possible the leaky oil filler cap could somehow be allowing the engine to
pull excess oil from the crankcase and inject it so to speak into the engine or
is it time to admit this one is a candidate for Vizardizing. Your opinions
please.
P.S. Planning on doing a leakdown test with compressed air on #3 & #4 to figure
out
if rings or valves.
Jim Gruber
Bugsy '68 Sprite (future Bugeye in disguise)
Dayton, OH
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