RE>Leak down test instrument

[Wade Jackson]

A compression tester has a one-way valve and measures peak cylinder
compression which should be 149-178 psi (unless you own one of the
special '96 sr20's).  You must manually release the pressure between
each test.

>A leakdown test cannot be done while cranking because the valves will
>keep openning and closing. :-)   So, you must pressurized a sealed
>cylinder (both valves closed) and let it leak down over time.

>A good engine will leak down very little over several hours.

George must have some very good engines!  :)

The pressurized air is continuously supplied.  One gage reads the
source, and one reads the cylinder pressure continuously.  The %
difference is the % leakdown.  For example on my SE-R, I had 3-4% loss
(96-97 psi cylinder and a 100 psi source).  My friend's rebuilt Talon
engine had 1-2% loss.  My cold SR20DET on a pallet had 7-8% loss.  I
think anything less than 10% is acceptable but it varies by engine.

Wade