Engine Running-in Guidance – 6 Steps to a successful engine rebuild

Click to download FULL PDF - Bulletin 1351

It is essential that every rebuilt engine undergoes a running in procedure. Only by optimising the running in procedure can oil control and fuel efficiency be attained. Failure to do so will result in excessive oil consumption because the piston rings have not been correctly "bedded in" or "seated" into the cylinder bore.

Vapormatic recommends the following 6 step process below to ensure a successful rebuild

1 Change the oil filter

It is also recommended to change all filters including fuel and air filters.

2 Fill with a SAE 30 Running-in oil

By using an SAE 10W-30 engine oil the mineral formulation will assist in avoiding bore glazing and provide protection for the valve train and associated components. This is important to allow the piston rings and bores to bed in and will assist the limited road use during running in. Do not re-use the existing engine oil or a use a low grade alternative

3 Flush the cooling system

Prior to engine testing, it is recommended that the cooling system is flushed out and checked for any faults or blockages. This is essential as rebuilt engines will typically have improved compression and, as a result, will run at higher operating temperatures so an efficient cooling system is vital. Additionally check that the fan belt is in good condition

4 Run/test the Engine

There is no universal set of instructions for running-in an engine however, there are consequences to an unsuccessful running-in. See full PDF download for details.

5 Check

After testing it is important to ensure that the valve clearances and cylinder head torque settings are rechecked to ensure there has been no movement. It is not necessary to re-check the cylinder head bolts on engines that use “stretch bolts” such as JDPS 300 and PowerTech series engines. The engine should then operate for the first 100 hours avoiding overloading, excessive idling and No load operations.

6 100 hour service

After 100 hours an oil change and filter replacement is mandatory. The running-in oil with have done it’s work and therefore, should be drained and refilled with a high quality oil, as recommended by the Original Equipment Manufacturer.

Please note: Failure to perform this ’running-in process’ will jeopardise the product warranty.

All Vapormatic quality replacement parts carry an industry leading 12 month parts and labour warranty. For further information on specific items please visit: