Quoting boostdtalon:
It was hot. A buddy reminded me about putting some oil in cylinder, so I'm going to do that today.
There's a couple things you can do to ensure the best readings.
safety first Throwing spark around a cylinder that's full of fuel can lead to external combustion, and a loss of eyebrows.
Disable the fuel injectors so they don't spray fuel into the cylinders while you're cranking the engine over. Spraying fuel creates a (small, but very real) fire hazard, and it will also wash down the bores leading to lower numbers and possible scuffing of the cylinder walls. Unplugging the cas is an easy way to disable the injectors (and ignition.)
Hold the throttle open while cranking to reduce the pumping losses. This will ensure the quickest build of cylinder pressure, and the most accurate readings.
Watch the gauge as the engine cranks. You should build a substantial amount of the final reading on the very first rotation. If it slowly creeps up, that speaks volumes about the rings.
The suggestion of adding oil and repeating the test on the low cylinders is an excellent one. If the numbers increase dramatically, you can suspect the rings aren't sealing well.
On a side note, I've found that many of the hoses used on two piece compression testers use the same fittings as many shops air line fittings. This means you can do a poor man's leak down test by bringing the cylinder you want to test to tdc on the firing stroke, and then thread the hose into the plug hole. Next, just pop the gauge off and apply shop air to the hose end to pressurise the chamber. (if you air line doesnt clip on to the testers hose, you can also use a rubber tipped blow gun attachment to pressurise things.)
Setting the compressor/air line pressure to 90 p.s.i. is a happy medium between getting enough pressure to seal the rings, and having too much pressure which will definately spin the engine off of tdc.
(don't forget to remove the ratchet in case the engine spins when you apply pressure
It wont give you any readings, but you'll be able to hear where the air is escaping, and draw some conclusions from that.
Air heard leaving thru the oil filler cap or dipstick tube means rings.
Air heard moving in the intake means intake valves
Air heard moving in the exhaust means exhaust valves aren't sealing well
Good luck, and post up your results!