Date: Wed, 26 Jan 2005 18:11:02 -0500
Reply-To: MilosKitchen <sagmoore@ZOOMINTERNET.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: MilosKitchen <sagmoore@ZOOMINTERNET.NET>
Subject: Re: How does a leak down tester work???
In-Reply-To: <67.3d237a45.2f292938@aol.com>
Content-Type: text/plain; charset="windows-1250"
Thank you Don,
The leak-down test is definitely done at top-dead center as this is where
the most piston / ring / cylinder wear occurs. If one cylinder has really
bad numbers during the test it may be possible to hear or feel leakage (air
hissing) at the intake manifold (remove the s boot), exhaust manifold, or
breather tower. When pressure is applied, if hissing occurs at either the
intake or exhaust manifolds, it may be a valve face or seat carbon deposit,
or it could be worse, valve or seat damage. One thing to try is to "stake"
the affected system valve. This consists of removing the rocker assembly,
reapplying pressure to the offending cylinder, and using a soft faced mallet
to strike the tip of the valve stem, unseating the valve under pressure. If
a piece of carbon has attached itself to the seat or valve face, this can
often knock it free. If it still hisses at the intake or exhaust, you have
real problems.
If you only hear hissing from the breather, recheck after squirting some oil
in the spark plug hole and cranking the engine (ignition and fuel pump
deactivated). If the pressure comes up, you may* only need rings.
Dave Milo
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Don Deitke
Sent: Wednesday, January 26, 2005 12:11 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: How does a leak down tester work???
The air test or leak down test is used to determine any wear problems within
any given engine . I will explain the test very simpily to all . // You want
to bring your piston to top dead center of each cylinder to be tested or
actually the firing position NOT to the bottom center. // You will first
remove all
4 sparkplugs from your engine,also your oilcap, and if watercooled your
radiator fill cap // You will need a air compressor with a adjustable air
regulator
plus a air test hose that may be purchased at your local parts stores and
it
will have a end to thread into the sparkplug hole and a male quick release
end to connect to your air hose. To run the test properly run and get the
engine to operating temperature before removing plugs. // Your FIRING ORDER
is
1-4-3-2 ~~ You have a V notch on your crank shaft pulley and that notch
will
show up on Number 1 cylinder and Number 3 cylinder. // You will need to
find
number 1 plug wire on your dist.cap and that will lead to the drivers side
towards the front of the van number 2 is on the drivers towards the back of
the van
Number 3 is on the pass.side towards the front of the van and Number 4 is
towards the back of the van // if you have standard shift place van in
neutral
and ebrake IT // Remove your distributor cap and turn the V notch to the
coresponding top dead center marks ~~refer to your Bently manual ~~ You
can
usually turn the engine on the alternator center nut ~ Turn engine
Clockwise //
Once you find Number 1 TDC // Insert your test hose into number 1 cylinder
then connect your air hose to the test hose with 0 air pressure at the air
regulator,slowly turn air up to 75 to 100lbs. Now if you have a problem in
the test
cylinder the air will tell the tale // to go to next cylinder to be tested
turn clock wise 90 degrees and make sure your rotor points to the correct
wire
on your dist cap // If a exhaust valve is leaking you will have air coming
out
the end of the muffler .// I f the intake valve is bad you will have air
coming out the air intake or on carbed out the carb.// If you have piston
,ring
or cylinder wear problems the air will blow past the rings and into the oil
area and you will be able to hear it at the oil fill region // If your head
gaskets are bad you will see air bubbles or antifreeze coming out the
radiator
fill cap .On horizontally opposed engines always replace the piston,cylinder
and
rings as a kit never replace just rings, you will be putting new round
rings
into 2 egg shaped objects = piston & cylinder NOW ??? The reason for
having
the piston at top dead center is to test the area at the top of the cylinder
and the rings for proper combustion which is the area IN which your power
and
compression originates from == Combustion ) ALL these tests can be done on
4
/ 6 / 8 cylinder engines.// You can have problems in all areas so listen in
all area,s to be sure . You should also run a a compression test first to
decipher any pre air test problems !!! Average good compression tis 150 to
170 lbs
We do not list parts on our Online Catalog for the early Air & Watercooled
Van, Vanagon or Bug ~~ But we do have a complete parts supply for the early
models / Just email or call in your Requests // For reference please
print the
test procedures and have it right on your test site !!! Any questions
just
email
Thanks to ALL Don @ DVW Online Catalog www.dvwimportautoparts.com
Ph. 814-266-9335
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