Re: keep blowing valve cover gaskets
Compression pressure is essentially the same whether your idling your engine or at WOT. If your your worried about too low a pressure which at your stated psi (130) - it's definitely conducive to combustion - but depending on you engine specs it might be too low. An easy way to tell if you have excessive ring/wall clearance is look at your exhaust. If it spits out lots of exhaust, especially blue smoke - bad (though this could mean your valve guides are shot also) . If you regularly are adding oil to keep it at the same level on the dip stick despite avg. boat use - bad. As others said, most likely you got a deformed mating surface on your thin walled valve covers. Good luck.
If this was true, then an engine would essentialy produce the same torque regardless of the rpm it was operating at...
Compression ratio is a constanst, but cylinder pressure has to increase with rpm. How can a cylinder at 5000 rpm that is drawing in more fuel and air not have a higher pressure than a cylinder at 600 rpm? All that fuel and air takes up more room in the combustion chamber, the valves shut, the piston squeezes, the spark plug fires and boom big pressure. At idle a relatively low amount of fuel and air comes in the cylinder, the valves shut, the piston squeezes, the spark plug fires and boom little pressure.
In the simplest of terms, this increase in pressures is what makes your exhaust louder as rpm increases, requires a increase in ignition timing to burn all that extra fuel and air, etc. Just think of an engine as an air pump as that's all it is. Ever pump up a bike tire with a manual pump? The faster you stroke the pump the quicker the tire inflates due to the increase in pressure (and this increase in pressure is what makes your arms tired faster).
Any easier way to check for excessive ring clearance is to do a dry compression test then do a wet compression test by squirting in a bit of engine oil into the cylinder being tested. If the gauge reading goes up considerably with the wet test, then you have a ring or excessive piston clearance concern as the oil will temporarily seal up the excessive clearance (unless a piston is severely damaged or you have a broken piston ring). But with his number of 130 psi I would imagine things are fine. Since the OP didn't indicate if he did his test with a well charged battery, all the spark plugs removed or with the throttle at WOT for his compression test we are all just guessing..
Okay enough thread hijacking...
To the OP, make sure your valve cover is flat, both surfaces need to be clean and dry. Purchase a good gasket and don't over torque the fasteners..
