[s-cars] Re: Pressure tester.

[Djdawson2 at aol.com]

Hey Chris,
Here's the deal....  When you simply put a fitting in the turbo intake line 
and pressurize it, you're actually pressurizing a whole bunch of things that 
don't require pressure.  This isn't a problem, provided you have an adequate 
supply of air to compensate for the losses.  I use a 60 gallon compressor.  
Needless to say, I can regulate the pressure down to about 10 psi (very safe for 
all things involved) and it would take quite some time to empty the tank.
  If you don't have a large volume of air to work with, you will have to more 
adequately isolate the intake tract.  Going in through the turbo intake will 
pressurize the entire crankcase, valve cover area, etc...  You will have to 
remove and plug any and all breather lines that would allow this to happen to 
effectively test with a small volume air tank.  Keep in mind that it may still 
be difficult.  When pressurizing the intake, you will also be pressurizing any 
cylinder whose intake valve is open.  You will also potentially loose large 
volumes of air rapidly through any cylinder that is in a position where valve 
overlap is occurring (intake and exhaust valves partially open in the same 
cylinder).  Likewise, if you have any significant leakdown in a cylinder receiving 
pressure, you will again be pressurizing the crankcase, leading to rapid 
depletion of a small volume air tank.  No matter how hard you try, a test of this 
nature will loose air somewhere, so large volume is your best weapon.
  Bottom line... IMHO, it is best to find someone with access to a large 
volume tank.   Pressurize the whole system to a reasonable level (10 psi), and 
then isolate your leaks.  Likely, opinions will vary.  But this has worked 
exceptionally well for myself, and numerous lister's cars that I've helped test.
Good luck, and HTH,
Dave in CO