High Quality Tester from Longacre
Racing Products
Quickly tell - from
the outside - when your engine needs an overhaul!This easy-to-use tester checks
ring seals, valves, even head gaskets. Don't wait too long to rebuil d that
expensive motor - but don't do it too soon either!
- Allows the
ability to achieve consistent power
- Stretch out the
time between costly teardowns
- Rugged design
features rubber bumpers to protect the gauges
- Exclusive
Longacre gauge manifold meters the airflow for precise readings
- 14 mm or 12 mm
plug adapter (choose size above)
Engine Leak Down
Performing a static
leak down test can be very helpful in determining if piston rings have begun to
leak, seated vales are sealing and if the head gasket is allowing compression
to leak into the cooling system.
The Longacre Leak Down Tester includes two gauges, a port for connecting to the
compressor, a port for connecting to the spark plug hole and a regulator. Leak
Down testers can use digital or analog gauges.
Testing should be done with the engine warmed up to normal operating
temperature. This is done so that the rings have expanded and will seal better
which should provide more meaningful numbers.
With a spark plug removed and the piston at top dead center, pressure (normally
100 psi) will be fed into the cylinder via the spark plug hole and the air
flow, which represents leakage, can be measured. For example, if the left gauge
is at 100 psi and the right gauge reads 95 psi, you have 5% leak down.
If you have high leakage, you should listen for air hiss in the following
areas:
- Exhaust
pipe – May indicate a burnt or stuck exhaust valve
- Carburetor
– Could indicate a bent or stuck intake valve
- Oil
filler or dip stick – Possible broken ring or piston
- Radiator
cap - Bubbles in the radiator indicates a leaking head gasket or cracked
head
Generally, racing
engines would be in the 1-10% range for optimum performance, although this
number can vary. Ideally, you would want to complete a leak down test when the
engine is fresh and use those numbers as your baseline.
Remember, like tire
pressure gauges, you should use the same leak down tester on the same engine
for a true comparison
