NOTE: Lubricate the bolt heads and threads. Use clean engine oil.
Install the LH and RH cylinder heads and tighten the bolts in six stages, in the sequence shown.
Stage 1: Tighten to 40 Nm (30 lb-ft).
Stage 2: Tighten an additional 90 degrees.
Stage 3: Loosen the bolts a minimum of one full turn.
Stage 4: Tighten to 40 Nm (30 lb-ft).
Stage 5: Tighten an additional 90 degrees.
Stage 6: Tighten an additional 90 degrees.