First start, running-in & after-fitting checks

Before you turn the key

• Oil level correct — check on level ground with the engine cold.
• Fuel system leak-free — inspect every hose, filter and carb/injector joint.
• Cooling tinware fully fitted — no test runs without the fan shroud, breast plate and cylinder deflectors.
• Fan belt tension correct — about 12–15 mm deflection at the longest run.
• Battery connected, earths clean and the starter motor wired correctly.
• Ignition timing set roughly to static spec before cranking. Fine-tune with a timing light once running.
• Valve clearances checked when cold if you fitted the heads yourself.

First start procedure

1. Crank without fuel — pull the coil wire or disable the pump and crank for 10–15 seconds to build oil pressure.
2. Reconnect and start. Do not rev it — let it idle at 1,000–1,200 rpm.
3. Watch oil pressure — it should come up within a few seconds. If not, stop immediately.
4. Check for leaks around the pushrod tubes, sump plate, oil cooler and rocker covers.
5. Listen for unusual knocking, rattling or scraping. Stop if anything sounds wrong.
6. Set timing and idle once the engine is warm and stable.

Running-in procedure

A freshly built engine needs gentle use while the piston rings bed in and bearing surfaces mate. The exact procedure depends on the build, but this is a safe general approach:

• First 50 miles — varied speeds, no hard acceleration, no sustained high revs. Let the engine load and unload.
• 50–500 miles — gradually use more throttle and higher revs, but avoid full-throttle hill climbs or motorway cruising at a constant rpm for long periods.
• First oil change — at around 500 miles, or sooner if the build is all-new. This flushes out bedding-in debris.
• Check and retorque cylinder heads, exhaust nuts and tinware after the first heat cycle and again at 500 miles.

Gearbox and clutch checks after fitting

• Clutch free play — adjust so the cable or slave has the correct travel. Too little and the clutch slips; too much and it will not disengage.
• Gear selection — every gear should engage cleanly from a standstill. Grinding or stiffness usually means shift-rod adjustment.
• Noisy gearbox — a little whine in top can be normal on some ratios, but clunks, grinding or vibration need investigation.
• Oil level — recheck after the first run when warm, and again at 500 miles.

Warranty and support

Every engine and gearbox we build carries a minimum 12-month unlimited-mileage warranty when fitted and run in correctly. Keep records of oil changes and any issues. If something does not feel right, stop and call us — it is always cheaper to check early than to repair later.

Read our full warranty terms and our engine fitting guide and gearbox fitting guide.