Flat tappet camshaft break-in is a critical procedure that must be done correctly. Wiped cam lobes — the most common early cam failure — are almost always caused by improper break-in or the wrong oil. Do not skip or rush this process.
WHY FLAT TAPPET CAMS NEED SPECIAL BREAK-IN: A flat tappet lifter slides directly against the cam lobe. During the first few minutes of operation, the lobe and lifter surface are "mating" — microscopic high spots are wearing smooth. If this process happens without adequate lubrication and a certain minimum RPM, the lobe surface overheats and fails. This damage is permanent and is not covered under warranty if caused by improper break-in.
OIL REQUIREMENT: Use an engine oil or break-in oil with a high ZDDP content for the first 20 minutes of operation. Look for an oil with at least 1,200 ppm zinc. Options include: • Dedicated engine break-in oil (recommended) • Classic-vehicle oil blends specifically formulated for flat tappet engines • Conventional oil with a ZDDP supplement added
Do not use standard modern API SN or SP rated oil for the break-in. These have reduced ZDDP levels that are inadequate for flat tappet cam break-in.
BREAK-IN PROCEDURE:
Step 1 — Pre-lube the cam: • Before installing the camshaft, coat every lobe generously with cam break-in lube or assembly grease. Do not skip this.
Step 2 — Start the engine: • After oil priming (see article SR-00116), start the engine. • IMMEDIATELY bring the RPM to 2,000–2,500 RPM. Do not let the engine idle.
Step 3 — Hold RPM for 20 minutes: • Maintain 2,000–2,500 RPM for a full 20 minutes. • Vary the RPM slightly throughout this period — let it drift between 2,000 and 2,500, don't hold it perfectly steady. • This keeps adequate oil flow over the cam lobes during the critical break-in period. • Monitor coolant temperature throughout — do not let the engine overheat.
Step 4 — Do NOT idle during break-in: • Low idle RPM reduces oil flow to the cam and lifters. During initial break-in, idling is not acceptable.
Step 5 — Shut down and change oil immediately: • After 20 minutes, shut the engine off and let it cool. • Change the oil and filter immediately. The break-in oil will be contaminated with metal particles from the mating process. • Switch to the recommended oil type for your engine type.
If you're unsure what oil to use or have questions about the break-in procedure, call us at 1-844-XPARTS-1 or email support@expediaparts.com.
