Pearson Boats - Common Systems > Engine and Drive Train
ALMA's trusty Atomic 4 out for first overhaul
T_schlueter:
A collet stud remover worked like a charm! Pistons and valves are out. Pistons and rings seem to be in decent shape. Valves are very sooty. Micrometer readings indicate minimal wear. I may have an expert take a look. I've reached a point where I'm quite unsure how to proceed.
Alma:
Good news. Your machine shop can make the measurements and guide you.
T_schlueter:
I replaced rings and cleaned and lapped valves. My measurements of cylinders and pistons seemed good enough not to require reboring. I've reattached the head and was hoping to compression test and can't get any compression whatsoever by handcranking. I did not remove cam or crankshaft. I staggered ring gaps. I must be doing something wrong. Could it be that hand cranking isn't fast enough or cranking "dry" has something to do with it?
Alma:
Its hard to say.
How did you hone the cylinders?
Are you sure the camshaft and crankshaft are in sync?
You should get some pressure against your finger at ta spark plug hole no matter what the cranking speed.
Are you sure you're cranking in the right direction?
Check rotation against the firing order.
My pistons ring lands were so bad that I used a quart of oil in just a few hours- still the engine ran acceptably.
Of course now it has far more power. It also will burn much more fuel-
But oil consumption is unmeasurable.
Make sure you're spinning her correctly first.
T_schlueter:
I used a drill driven hone to remove a little glazing on the cylinder walls.
I didn't remove either crankshaft or cam shaft so syncing should be ok. The crankcase is not installed nor is valve inspection plate so I can visually check positions of pistons and valves.
I am cranking counterclockwise. Later today I poured a bit of oil in cylinder #3 and was able to register 15 lbs. I'll install starter and figure how to wire it up to a battery and crank it that way to increase revs in case that helps somehow.
I may try forcing air into spark plug holes at TDC and look/listen for leaks.
Maybe I have a bad tester!
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