The first 20 minutes after startup are absolutely critical for both hydraulic and solid flat tappet camshafts. This is when the face of each lifter mates to its cam lobe. Get it wrong and you can wipe out a brand new camshaft before it ever gets to show what it can do.
Before you begin
Verify that the camshaft and all valvetrain parts are compatible, especially the valve springs. For applications with heavy springs, we recommend running lighter springs during break-in, or removing the inner spring (on dual springs) for the break-in period only.
Never assume parts arrive clean. Always inspect cam bolts, spring retainers, springs and other components for damage before installation.
Preparation
Change the oil and filter before installation. Fill the crankcase with fresh, clean engine oil. Many modern oils lack sufficient additives for flat tappet cam break-in, so choose an oil with high zinc content (ZDDP) or use a separate break-in oil additive.
Wash the camshaft and lifters thoroughly in clean mineral spirits to remove the rust preventative applied before shipping.
Installation
Do not pump up hydraulic lifters before installation. Doing so can hold a valve open during cranking, causing low compression and delayed startup, which is extremely damaging during break-in.
Coat the lifter faces, the cam lobes and the distributor gear with the supplied moly paste. Then set the valve lash or lifter preload. Keep the number of engine rotations to a minimum, since turning the engine over can wipe the paste off the lobes.
If possible, prime the oil system before startup. Rotate the engine at least one full revolution to make sure oil reaches all valvetrain components. Leave the valve covers off so you can see that every rocker arm is getting oil.
First start and break-in
- Set the ignition for a fast idle before starting. The engine must fire quickly without unnecessary cranking.
- Start the engine and immediately bring it up to 2,500 rpm.
- Vary the engine speed between 1,500 and 3,000 rpm in a slow acceleration and deceleration pattern.
- While it runs, check for leaks and unusual noises. If anything sounds wrong, shut the engine off and find the cause.
- Continue the varying break-in cycle for a total of 20 to 30 minutes. This is necessary for proper lifter rotation, so that each lifter mates to its lobe.
If the engine has to be shut down for any reason, go straight back up to 3,000 rpm on restart and continue the break-in until the total running time reaches 20 to 30 minutes.
After break-in
Let the engine cool, drain the oil and change the oil filter. Refill with a premium oil. The initial break-in is now complete. Drive the car normally, but change the oil and filter again after 1,000 km.
Important to know
- Never run used lifters on a new camshaft. Lifters and cam lobes mate to each other during break-in (for demanding engines there are also DLC-coated lifters as an alternative). If lifters come out of the engine, they must go back on the same lobe.
- Spring pressure: Do not exceed the recommended open spring pressure. Racing applications often run higher pressures at the cost of camshaft life.
- Lifter rotation: Flat tappet cam lobes are ground with a slight taper that makes the lifter rotate. This rotation draws oil across the contact face. Check that the pushrods are spinning during break-in as a sign that the lifters are rotating properly.
Meksta recommends always buying the camshaft and lifters as a matched set to minimize the risk of failure during break-in.
Also read about camshaft wear, camshaft materials and flat tappet lifters.