Air pressure tester for intake hoses & IC: 200q20v digest.

Eric_R_Kissell at Eric_R_Kissell at
Wed May 21 08:57:08 EDT 2003

Chuck Pierce <cpcycle at> asked:
>When pressurizing the intake system to do this check,
>doesn't air go out a open valve?

If an intake valve is open, the pressure goes into the cylinder and is held
by the exhaust valve which is usually closed.

If an exhaust valve is open the pressure usually cannot get into the
cylinder because it would have to get by a closed intake valve.

If an intake and exhaust valve are open at the same time (i.e. valve
overlap) then you have a leak path.

We need to ask:  Is there overlap?

Eric Kissell

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