Galloway Engines

Pressure Testing

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The team at Galloway Engines is continually committed to ensuring only quality, precision work is produced. Provided below is a series of technical bulletins which detail some of the methods employed by our technicians as well as additional informatio

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Pressure Testing

The importance of "pressure testing" cylinder heads and blocks cannot be overstated.  An engine is a precision machine where minor imperfections can cause catastrophic effects.

The importance of "pressure testing" cylinder heads and blocks cannot be overstated.  An engine is a precision machine where minor imperfections can cause catastrophic effects.  Avoiding the risk of engine unreliability or failure is paramount.  All blocks and cylinder heads should be pressure tested prior to reconditioning.  It would be no surprise that major engine part manfacturers recommend that high quality pressure testing is carried out prior to reconditioning the engine.

Traditionally, pressure testing has been a time consuming operation, which has labelled the process as costly and consquently has been avoided by customers.  There have been major developments and improvements in the automotive engineering industry over the years.  Unfortunatley, pressure testing of cylinder heads and blocks during the reconditioning process has been neglected, unti now....

The Newclear Pressure Tester is a revolutionary machine that has the ability to test for cracks and defects in cylinder heads and blocks.  Pressurised water is flowed through the casting to simulate operating conditions.  The inline heater system allows hot and cold hydraulic testing, in addition to air testing, at capabilities up to 800kPa.  To put this into perspective, cylinder heads normally run pressure in the water system at around 100 - 200 kPa.  Under high pressure, cracks will inevitably show up.  With the ability to pressure test between 400 and 800kPa, depending on the head, there is assurance that problems with the component will be positively identified.

The combination of light weight aluminium cylinder heads with cast iron blocks means good quality hot and cold pressure testing is essential.  The difference in the expansion rates between aluminium and cast iron vary greatly and it is vital that fractures and porosity in the cylinder heads are detected.  It is not only overheating that can cause cracks in the head. Fractures can ofter occur upon engine disassembly (the head stress relieves and the head cracks). Often fractures are only visable after a cold hydraulic test followed by a hot hydraulic test, followed by a cold hydraulic test.  These three tests are carried out in rapid succession - a process which is not possible using traditional pressure testing methods.

The main attribute of the Newclear Pressure Tester is in its design feature, which allows full access to the component and clear visiblity.  The adjustable centre of gravity allows the cylinder head or block to be easily rotated 360 degrees.  While the transparent pressure plate enables the machinist to identify the exact point where the head or block may be leaking.


The machine is able to pressure test a large variety of cylinder heads and blocks as it contains a full kit of rubber plugs which are adaptable to many different configurations to block off water jackets, which allows the system to be pressurised.  The process is simple and quick to set up, making th test efficient and effective.  By having the correct machine, 70% on setup time can be saved.

Once a cylinder head or cylinder block had been pressure tested and fractures have been identified, the decision on whether the component may be repaired or whether replacement will be required, can be made.

The Newclear Pressure Tester is capable of pressure testing automotive, marine and heavy duty industrial cylinder heads and blocks.  Contact Galloway Engines for more information on this service.

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