Whats the equip/procedure for leakdown test?

[cstreit]

Can anyone give me the procedure and equipment needed for a leakdown test?

Thanks,

chris

[Zeke]

There are 2 gauges, some air hose and a spark plug hole adaptor. The first guage is fitted with a regulator so you can introduce a predetermined air pressure into the cylinder. Many use 100 lbs. as the percentage of leak down is what the pressure is on the other gauge, i.e., the second gauge says 90, you have a 90% containment.

I got ahead of myself. After the air presssure is introduced, the air supply is shut off. The second gauge monitors the air pressure in the cylinder. Each cylinder is timed the same for pressure loss.

Look here: http://www.thetoolwarehouse.net/shop/STR-CLT2PB.html

[304065]

Chris,

Wayne sells the identical leakdown tester, I just bought one (probably for the same reason YOU bought one. . . )

Make sure the engine is warm. I would recommend driving it for a few minutes, then shut down and wait about five minutes, so you don't gall the plugs when you remove them.

Set #1 cyl to TDC. Both intake and exhaust valves closed. Insert the leakdown tester into the spark plug hole and apply 100 psi air. As Milt says, the air is then shut off, and a stopwatch started. At the end of a preselected interval, say 10 seconds, the exact reading on the gauge is noted, e.g. 94#. This is the percentage of leakdown. Anything over 20 is bad.

You probably know the rest: a high reading suggests a bent or burned valve or bad rings, and you listen to the airbox, tailpipe, or crankcase breather to determine where the air's getting out. (Either that or you didn't get the cylinder to TDC and one valve is open. . . )

Good luck! Somebody should make a rev limiter that works when you downshift. . .

[john70t]

"Somebody should make a rev limiter that works when you downshift. . "
There's an idea for Chuck Moreland.
A harmonic fan pully assembly that incorporates a frictional drag assembly with expotential drag over a certain RPM? Mabye electromagnets to save weight?
Sorry, it's late.....

[dad911]

Originally posted by john_cramer
As Milt says, the air is then shut off, and a stopwatch started. At the end of a preselected interval, say 10 seconds, the exact reading on the gauge is noted, e.g. 94#. This is the percentage of leakdown.

My gauge doesn't involve a stopwatch. Dual gauge, with regulator. Directions are as follows:

1) warm engine, turn off
2) remove all spark plugs, air cleaner, and crancase filler cap
3) rotate crankshaft until cylinder being tested is at Top Dead Center on compression stroke
4) install adapter into spark plug hole
5) connect tester to adapter
6) connect adequate air source to tester. Air source should be 10 P.S.I. greater than regulated input pressure shown on left gauge
7) The relative pressure of the cylinder is shown on right hand gauge

then there is a chart converting pressures to %. For example, 90# in and 81# out is 10% leakage.

good luck!