bad compression

[Alex7747]

So a couple days ago i did a compression test and it came out 110 a cross the board .. my question is, what are some tests to find the problem? i have (at idle) 20 psi of vacuum. is that normal..if i have such high vacuum and low compression?
i tried to perform a leak down test but I'm not really sure on how to even get a reading?.
I was going to do a wet compression test to check the rings but i heard somewhere that if the oil is poured into the cylinder and it stays on the piston (i have the stock 2g pistons so their like bowls) the readings would be point less..
so I'm looking on advice on how to diagnose my low compression . the car still pulls okay but i would really like at least 160 psi. so i need help...
oh yeah i read that foam in the coolant could mean a bad head gasket? how could i check for this? (the bad head gasket, i have foam in the coolant).

Thanks ahead of time
oh and one more thing, when the cars at idle and i remove the oil filler cap i can feel a lot of air coming out if hold my hand over the hole. any thoughts?

 

[Alex7747]

Uh, not quite. If you have a blown headgasket, it will SHOOT coolant out of the cap.

Example's:

Buddies civic had coolant dripping off the ceiling of my garage after he cranked, not started, it with the cap off.

My s-10, coolant all over the engine bay and hood after cranking, not starting, it with the cap off.

That is just a few of the many that I have seen do this.

in that case my headgasket wasn't blown (it really wasn't).. I'm sure my low compression numbers were because the cylinders were never honed ... either way, the engine is being rebuilt the RIGHT way now so..../thread.