What is the procedure a machine shop uses to pressure test a block? I have a 59 block with no visible cracks. I'm thinking if I seal the deck and water pump surfaces, and the water jacket holds 10# of air pressure for 24 hrs. it would indicate no cracks. Am I thinking correctly or am I missing something?
Block Pressure Testing
- Thread starter rustynutz
- Start date
Karl Wolf
Well-known member
I have done this a lot... Block all the water holes. Use 30 lbs air. Take a squirt bottle with a bit of soapy water and look for bubbles inside, outside, pan rail, behind valve springs... With my pressure test rig, I find that I can get 80 plus lbs air to hold- with minor leakage...
Pressure test will find leaks, but not all cracks leak... I'm thinking in the cylinder/ valve seat area. Magnaflux is also called for in these areas, and if you think to, you could look for cracks around the center main bearing.
Karl
Pressure test will find leaks, but not all cracks leak... I'm thinking in the cylinder/ valve seat area. Magnaflux is also called for in these areas, and if you think to, you could look for cracks around the center main bearing.
Karl
D. Jones
Well-known member
A word of caution about pressure testing to very high pressure. I was given the remains of a 59-ab engine by a friend after someone pressure tested it at 165 psi and blew out a pea sized piece of the block in the #5 intake valve guide pocket. That is a very thin area and with many years of rusting it just couldn't take that high a test pressure. Some guys test to 100 psi, but I don't see the need as stock they only ran at 4 to 7 psi. My personal feelings are that 20 psi is more than enough. Fortunately I was able to repair the damage and am running that engine in my 46 1/2 ton.