Mayday, mayday!!!

[JT]

My daily driver (NOT my Cobra) had low compression in one cylinder. I found a cracked head and replaced it. Now the compression is still real low and the oil...well, you know. I need to know if the block is cracked before I trash the entire engine. How do I make sure-cooling system pressure test? cylinder pressure test?
This is enough to really piss a guy off. Thanks for the advice.

Damn
Damn
Damn
Damn
Damn I hate to hemmorage money.

[Roscoe]

Did you squirt some oil into the cylinder and recheck the compression. This would be a sign of a bad ring. Assuming the valves are ok.

For a pressure test you would hook up a gauge to your coolant inlet and start the engine. Rev it up and see if you get pressure. This would indicate a blown gasket or crack. Do you have coolant in the oil? Oil in the coolant?

You can also do what is known as a cylinder leak down test but I don't know much about that.

Roscoe

[Mr.Fixit]

Another way to check,
Use the adapter hose that came with your compression tester that screws into the sparkplug hole. (or your leakdown tester if you have one) Take the cylinder in question to BDC, pressurize the cylinder with 100psi compressed air, with radiator cap removed, look and listen for air bubbles. Have all the sparkplugs out of adjacent cylinders, if the head gasket blows between two cylinders, you will hear the air coming out the neighboring sparkplug hole. This is similar to a leakdown test, but without recording any numbers to find the "leakdown rate"

[JT]

Thanks for the replies. I pulled the head again and found nothing apparently wrong (I hope I got a wrong gasket or something). Anyway, I got a new engine on the way, so out this one comes and it will become a rainy day project. Looks like Carrol Shelby isn't the only one getting a "heart transplant". Allright-bad joke, but at least I'm laughing a bit. Thanks, fellow gearheads.