Not sure why you posted again or what the hell your on about mate. Sounds like your a few cans in.
Was hoping for something constructive like "if you lose a psi a minute you should be ok" and save me a few hours work.
If you know what you're actually talking about.
I guess its easier to be a smart ass and try to look cool on the forum.
Internet issues are the reason for the double up. I do apologize for being an ass and there's no excuse for that, seriously. I type like I talk and the words don't always match my ugly ass goofy mug.
For what its worth read groupk's article on air leaks. They want 6 to 9 psi held for 8 to 10 minutes. I've tested motors that don't lose a pound of pressure and others have lost most after 10 minutes. My biggest headache was a 1 cylinder 300sx motor that leaked more air than I thought possible.
30 psi is ridiculous, pump up a crank case to that and something is getting damaged. You want to test operating conditions not brute force torcher testing.
And just to add to what sparkplug said, you would think if something holds pressure it would hold a vacuum but thats just not true. Direction of mechanical forces make a huge difference. Not that it matters for our purpose here but I operate machines for a living that can hold pressure (15k to 25kpsi ) but the job gets stopped because it can't hold a 3 torr vacuum for 10 minutes and the reason is the mechanical and wearable seals fail when pushed the opposite way.
groupk.com
