Tech Tip - Flat Tappet Cam break-in

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Important Camshaft Break-In Information for Flat Tappet Cams

The following information should be considered for any engine that uses a flat tappet design and should be referenced before initial start-up. Current anti-wear protection in today’s engine oils used by engine manufacturers in new car production may not be suitable for initial flat tappet break-in.

These oils are less compatible with flat-tappet designs than older formulations with better wear additives than the current SM category oils. With the advent of roller lifters, and cams, as well as roller rockers, the need for those expensive elements has diminished.

There have been numerous reports of premature flat tappet camshaft failure. This has been an issue of late and not just with one brand or type of camshaft. In almost every case, the hardness or the taper of the cam lobe is suspected, yet most of the time that is not the problem.

This growing trend is due to factors that are unrelated to camshaft manufacture or quality. Changes in today’s oil products and “advanced” internal engine design have contributed to a harsher environment for the camshaft and a potential for failure during break-in. However, there are several steps to counter this trend.

It is recommended that you use oils with higher levels of wear preventive additives that may be more desirable during flat tappet break-in. The higher a motor oil’s Total Base Number (TBN), the more effective it is in handling contaminants and reducing the corrosive effects of acids for an extended period of time. TBN is the measurement of a lubricant’s reserve alkalinity.

Melling and Melling Select Performance offer Mell-Lube, camshaft lube, (Melling p/n M-10012). Use liberal amounts when installing new camshaft and lifters.





Recommended Camshaft Break-In Procedures

In order to give your camshaft and lifters the best possible chance to make it through the first crucial moments of operation upon initial startup and provide a long, trouble-free service life, the following is recommended:

Pressure Tank System: The pressure tank system is by far the best method of making all air is purged from the oil galleys. Prelube until oil is seen at the rocker arms. Use oil that is recommended by the manufacturer, do NOT use a non-detergent oil.

Spinning The Oil Pump: Using a priming tool, turn the pump with a drill until oil is seen at the rocker arms. Priming tools are available from Melling.

Free Spinning The Engine: Remove the spark plugs and turn the engine with the starter until oil pressure is noted on the gauge (Note: not the preferred method).

Before Starting: Set the timing and be sure fuel is in the carburetor or injection before cranking. This will assure the engine starts with the least amount of cranking.

Start The Engine: After it starts, check for oil pressure and bring the rpm to 1,500-2,000. If the pressure is good, run the engine at this rpm range for 20 minutes. After this run in period, final adjustments can be made and the engine put in service.

Source: Melling Engine Parts (www.melling.com)