Mityvac 05530 User Manual [en, es, fr]

COMPRESSION TEST KIT

MODEL 05530

www.mityvac.com

OCT - 04 Section

Form 823541

- MV18

Page

- 1A

823437

©

Hose 14MM Long Reach

823441
Field Service Kit

823436
Hose 14MM Short Reach

823438
Hose 18 MM Short Reach

823435
Hose 14MM
Short Reach

823434
Gauge, Valve
and Hose

823433
14MM - 18MM
Adapter

823431
10MM Adapter

823432
12 MM Adapter

823442

823440

Plastic Case

Pressure Hold Adapter

Part No. Description Part No. Description

823431 10M M Adapt er 823437 14 M M Long-Thread x 12 in. (305 MM) Long Hose©
823432 12M M Adapt er 823438 18 M M Shor t - Thread x 12 in. (305 MM) Long Hose
823433 14M M Female - 18MM Male A dapt er 823439 Gauge
823434 Gauge Assembly 823440 Pressure Hold A dapter
823435 14 M M Shor t-Th read x 6 in. ( 150 MM) Long Hose© 823441 Field Servic e K it
823436 14 M M Shor t-Thr ead x 12 in. ( 305 MM) Long Hose© 823442 Case

© Indicates change

Page Number - 2

Form 823541

Always read instructions carefully prior to use.

Included in this Kit

• Heavy duty 2 ¾” (70 mm) gauge with high impact
lens, rubber boot, and three (3) scales of measure
(psi, kg/cm2, bar), attached to 10" (250 mm) hose and
quick release coupler

• Four (4) extension hoses:

• 6 ½” (165 mm) long x 14 mm thread, short

• 12" (305 mm) long x 14 mm thread, short

• 12" (305 mm) long x 14 mm thread, long

• 12" (305 mm) long x 18 mm thread, short

• One (1) adapter: 14 mm thread, short x 18 mm
thread, long

• Two (2) small engine adapters

• 10 mm thread

• 12 mm thread

• One (1) quick release air hold adapter

• Custom blow-molded case

• Field service kit

pounds higher than the other cylinders, the probable
cause is carbon build-up inside the cylinder.

The Mityvac Professional Compression Test Kit can
perform two tests: the dry compression test and the wet
compression test. The result of performing these tests
will provide an indication of the condition of the piston
rings, the cylinders, and valve-train.

Dry Compression Test Procedures:

1. Refer to the appropriate service manual for the
compression specifications specific to the engine you
are testing.

2. Start engine and allow engine to run until it reaches
normal operating temperature (usually about 15
minutes.) Turn engine OFF.

3. Install an auxiliary starter switch in the starting circuit.

Applications

The Mityvac Professional Compression Test Kit can
perform dry or wet compression tests to determine the
amount of pressure produced in the cylinder of an
engine. It can also be used as a tool for pressurizing an
engine cylinder to hold the valves closed while perform­ing repairs.

How to Perform a Comression Test
Precautions & Diagnostic Notes:

WARNING: DO NOT use the ignition switch during the
compression test on fuel-injected vehicles. Use of a
remote starter switch to crank the engine is recom­mended. Fuel injectors on many late model vehicles
are triggered by the ignition switch during the cranking
mode, this could result in a fire hazard or contamina­tion of the engine’s oil with fuel.

Always use eye protection when performing compres­sion tests.

An engine in good operating condition will produce a
certain amount of pressure in each cylinder. Normally,
the cylinders should be within 10 percentage points of
one another and within the manufacturer’s specifica­tions. The pressure should rise smoothly on each
stroke of the engine, until it reaches a peak.

If the pressure reading fails to rise, or it remains the
same for several strokes of the engine and begins to
rise, the likely cause of the problem is a sticking valve.

If two adjacent cylinders show pressure readings of 20
or more pounds below the other cylinder readings,
suspect a blown head gasket.

If a cylinder shows a pressure reading of 15 or more

4. While wearing eye protection, use compressed air to
carefully remove dirt and debris from the area around
the spark plugs.

5. Remove spark plugs one at a time, marking the
number of the cylinder they were removed from, and
place them on a clean flat surface. This will aid you in
identifying problem cylinders by allowing the compari­son of spark plug appearance to the compression
level of a given cylinder.

NOTE: When testing engines with two spark plugs
per cylinder, it is only necessary to remove the
spark plugs located on the exhaust side.

6. On vehicles with standard distributors, disconnect the
coil wire (high tension lead) from the distributor cap
and secure it to a suitable ground, or disable the
ignition by disconnecting the positive (BAT) terminal
from the ignition coil.

7. On vehicles with a distributorless ignition (DIS),
disable the ignition system by removing the electronic
ignition (control) module fuse, or disconnect the crank
angle sensor.

NOTE: Refer to the appropriate service manual to
determine which fuse or component to temporarily
remove or disconnect.

8. Remove air cleaner from carburetor or throttle body
and secure throttle linkage in wide-open throttle
(WOT) position.

NOTE: NEVER place anything inside the throttle
body; internal damage to the engine could result. On
vehicles equipped with port fuel injection, remove
throttle linkage covers (as necessary) and secure
throttle linkage in the wide-open throttle (WOT)
position.

Form 823541

Page Number - 3

9. Crank engine several times to ensure removal of any
foreign matter that may have fallen into the cylinders
during preparation for test.

3. Thread the assembly into the cylinder spark plug hole
until the o-ring on the adapter seats firmly (do not use
a wrench to tighten).

10.Select the appropriate adapter fitting (14mm, 18mm
short reach or 14mm, 18mm long-reach), and thread
adapter into spark plug hole of cylinder head.

11. Connect the appropriate test hose or adapter to the
gauge assembly.

12. Crank the engine at least five compression strokes or
until the pressure reading stops increasing on
gauge.

13. Read the pressure level on the gauge and record the
reading along with the cylinder number being tested.

Example: #1-150 psi, #2-145 psi, etc.

14. Repeat this test on each cylinder. If any of the cylinder
readings are found to be low or uneven, perform wet
compression test.

15. When compression test is complete, return the
spark plugs to their respective cylinders and the
throttle and ignition components to their normal
positions.

Wet Compression Test Procedure

CAUTION: DO NOT perform the wet compression test
on any diesel engine. The higher compression in a
diesel engine may cause engine damage or injury to
the technician.

4. Ensure the spark plug is grounded to the cylinder
head or is insulated in a way that will prevent an
electric shock hazard.

5. Crank the engine over using the pull cord (or starter if
electric) a minimum of 5 revolutions. This will allow
the cylinder to build sufficient compression to be
measured.

6. Refer to the manufacturer’s data to determine the
correct reading

Using the Pressure Hold Adapter

The Mityvac Professional Compression Tester comes
with a pressure hold adapter. This adapter is used to
perform valve seal replacement on an engine without
removing the cylinder head(s). To use the adapter:

1. Remove the spark plug from the desired cylinder.

2. Select the appropriate extension hose that will fit the
spark plug hole.

3. Using the valve core tool (from the field service kit
included), remove the valve core from the end of the
hose and lay it aside.

4. Thread the extension hose into the spark plug hole
until the o-ring seats; do not use pliers or a wrench to
tighten.

The wet compression is a way to remove the influence of
the piston rings, pistons and cylinders from the com­pression test. After completing the dry compression test,
squirt approximately one teaspoon of engine oil into the
spark plug holes and crank the engine several times to
seal the piston rings. Repeat the dry compression test
outlined above. NOTE: If the readings during the wet

compression test are greater, then air is leaking around
worn or damaged piston rings. If the reading is approxi­mately the same for both wet and dry tests then the
valves, valve lifters or the camshaft lobes are worn. Any
low reading of cylinder compression indicates worn or
damaged parts.

Small Engine Compression Testing

The Mityvac Professional Compression Test Kit has two
(2) adapters, 10mm and 12mm, that allow it to be used
on small engines found in lawn mowers, chain saws
and line trimmers. To use these adapters:

1. Disconnect the spark plug wire and remove the spark
plug.

2. Thread the appropriate size adapter onto the com­pression tester main hose end until the o-ring seats
(do not use a wrench to tighten).

5. Attach the Air Hold Adapter to the extension hose.

6. Attach a shop air hose to the Air Hold Adapter, this will
maintain air pressure in the cylinder to hold the
valves closed while performing repairs. (It may be
necessary to rotate the engine until all valve are
closed and air is holding in the cylinder)

Note: Air Hold quick connector does not come with a
compressed air line fitting to adapt to your air source.
This will have to be purchased separately to fit your
system.

Contacting Lincoln Industrial Corp.

Lincoln Industrial Corporation,
One Lincoln Way,
St. Louis, MO 63120
Phone: [phone] Ext. 4410
Fax: [phone]
E-mail: [e-mail]
For technical questions, please contact our Technical
Service Department:
Phone:[phone] Ext 4782
Fax: (314) 679-HELP (4357)
E-mail: [e-mail]
Visit our Web Site at: www.mityvac.com

Page Number - 4

Form 823541