High Compression on 1 cyl

[sixpac]

1,3,5,7,4,6,8 = 180 lbs, 2 = 230 lbs, what would ya be looking for to cause high compression in that 1 cyl ?

running 93 octane, in a 25 ft excalibur, bravo one with 22" prop, engine runs out strong and hitting on all 8, idle and wot.

615 ci bbc with @ 80 hrs, merlin tall block, lunati crank, comp cam, roller lifters, canfield heads, all worked and assembled by machine shop, engine uses 4-7 swap, compression was taken cold, warm up and retest comp on 2 drops to 195.

ive pulled valve cover and checked that valves appeared to have correct lift and not tight.

broken oil ring or valve guide leaking excessive oil into cyl 2 ?

[Rivernut]

Exhaust valve not opening - collapsed lifter or broken rocker assembly. Could also be Carbon build up.

[sixpac]

carbon build up on 80 hr motor that shows 230 cold and 195 hot just dont add up, coarse if oil deposits has been an issuue from start could relate to high comp, collapsed lifter and broken rocker rocker arm have been ruled out, valve cover has been removed, rocker ass has been inspected, exhaust valve is opening as well as intake and appears full lift.

noticed on last outing blue smoke from exhaust after extended off period.

really dont want to pull engine but may have too.

not my build, but may have to correct.

[Rivernut]

How does the #2 spark plug look?

[sixpac]

plug looks good, yellow-ish tan line / clean electrode no deposits, carb seemed to be loading up at idle so i pulled the bowls and found the power valve not closing at rest so change it and tune.

[Rivernut]

I assume you have no earlier compression test to compare as a baseline. Unless you have used a dial indicator and a degree wheel to measure valve lift and duration, then you really don't know if there is a net difference between cylinders in lift. Duration and lift have a huge affect on cranking PSI. I know it is a pain to try to do that on an installed engine. Maybe the #2 exhaust cam lobe is low. Something easier to check is the #2 exhaust pushrod. Make sure it is not bent or improper length. I'd also perform a leak-down compression test to rule out head gasket issues. The newer multi layer steel head gaskets sometimes leak when cold, and head gasket leaks can leak in, out, or both directions. If it were leaking in only from any passage it would cause a higher reading.

[sixpac]

ive run comp test at early times for comparison and had the same results, really dont want to pull engine for inspection, i am thinking improper breakin and /or assembly, could be valve train related.

was just wondering if i missed something, think ive done all i can with eng still in boat.

[Superstocker]

Sounds like you have some sort of liquid in the cylinder; probably oil but maybe water or fuel... I seriously doubt that valve train damage or improper setting could raise the compression like that without a definite power loss.