Sealey CT951.V4 Manual

Thank you for purchasing a Sealey product. Manufactured to a high standard, this product will, if used according to these
instructions, and properly maintained, give you years of trouble free performance.
IMPORTANT: PLEASE READ THESE INSTRUCTIONS CAREFULLY. NOTE THE SAFE OPERATIONAL REQUIREMENTS, WARNINGS & CAUTIONS. USE
THE PRODUCT CORRECTLY AND WITH CARE FOR THE PURPOSE FOR WHICH IT IS INTENDED. FAILURE TO DO SO MAY CAUSE DAMAGE AND/OR
PERSONAL INJURY AND WILL INVALIDATE THE WARRANTY. KEEP THESE INSTRUCTIONS SAFE FOR FUTURE USE.
Refer to Wear eye
instructions protection
1. SAFETY
WARNING! Ensure all Health & Safety, local authority and general workshop practice regulations are strictly adhered to when using
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tools.
DO NOT use tester if damaged.
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DO NOT use the tester for a task it is not designed to perform.
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Maintain the tester in good and clean condition for best and safest performance. Use an authorised service agent.
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Wear approved eye protection. A full range of personal safety equipment is available from your Sealey stockist.
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Wear suitable clothing to avoid snagging. Remove ties, watches, rings and other loose jewellery and contain long hair.
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Maintain correct balance and footing. Ensure the floor is not slippery and wear non-skid shoes.
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Account for all tools and equipment being used and do not leave them in, on or near engine.
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Keep the work area clean, uncluttered and ensure that there is adequate lighting.
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DO NOT operate the tool when you are tired or under the influence of alcohol, drugs or intoxicating medication.
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When not in use, place in original protective case and store in a safe, dry, childproof location.
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Always refer to the vehicle manufacturer's service instructions or a proprietary manual, to establish the current procedure and data.
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2. INTRODUCTION
Large easy to read gauge with imperial and metric readings. Side release valve and 12" flexible hose for easy reach. Pressure range
0-300psi/0-2000kpa. Screw in 14 and 18mm adaptors and 150mm rigid stem cone adaptor fits most spark plug holes. Supplied in storage
case.
3. OPERATION
3.1. PREPARATION
3.1.1. Run engine until normal operating temperature is achieved.
3.1.2. Stop engine, loosen spark plugs one turn, with an air hose, blow dirt and debris from the spark plug wells.
3.1.3. Remove all spark plugs.
3.1.4. If fitted with a carburettor set the throttle valve wide open.
WARNING! The ignition system MUST be disabled. Failure to disable could result in damage to the ignition system or ECU.
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3.1.5. Unplug the low tension connections to the coil. If you aren't sure how to disable the vehicle ignition system then consult the
manufacturer's service instructions or a proprietary manual before you start. It is also good practice to unplug the fuel injectors or
disable the fuel pump, especially on cars fitted with a catalytic converter. This prevents unburned fuel getting into the exhaust system
during the test.
3.2. COMPRESSION TEST
3.2.1. Using the appropriate threaded adaptor, screw the tester (fig 1), into a spark plug hole (finger-tight - do not use a wrench) or using
the push fitting (fig 2), hold the compression tester firmly against the spark plug aperture.
3.2.2. Crank the engine until no increase in pressure is noted on the gauge reading; usually 3 or 4 revolutions is sufficient. Take a note of the
pressure reading.
3.2.3. Decompress tester by pressing release valve (fig 1) remove the compression tester from the spark plug hole and proceed to the next
cylinder. Note pressure reading for each cylinder.
NOTE: The actual figure in psi is not important. It is important that all cylinders have approximately the same compression pressures.
On high compression engines (150psi and higher) the pressure should not vary more than 15psi from the highest to the lowest
cylinder reading.
On low compression engines (under 150psi) the pressure should not vary more than 10psi from the highest to the lowest cylinder
reading.
NOTE: Compression readings are unbalanced when one or two cylinders are considerably higher or lower than the others.
3.3. CAUSES OF UNBALANCE
3.3.1. Low cylinder compression is caused by leakage from:
A. Head Gasket - explosive sound when running engine.
B. Head Gasket between cylinders - compression will be low in two adjacent cylinders and water may appear in cylinders or
crankcase.
C. Valves that are not seating properly.
D. Piston rings that are worn. Pour a teaspoon of oil into the spark plug hole to seal the rings. Repeat test.
© Jack Sealey Limited
PETROL ENGINE COMPRESSION TEST KIT
3PC
MODEL NO:
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Original Language Version
CT951.V4
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CT951.V4 Issue 1 11/03/22