Ford F77Z-6505-AA Exhaust Valve

Formula. Thickness required (D) = C + B - A, where A = Desired clearance, B = Measured clearance, C = Tappet thickness found. Example, clearance too small: A = 0.25 mm, B = 0.09 mm, C = 2.55 mm, D equals 2.39 mm, use 2.39 mm shim. Example, clearance too large: A = 0.30 mm, B = 0.36 mm, C = 2.19 mm, D equals 2.25 mm, use 2.25 mm shim. Measure with engine cold, recheck after installation, and use quality shims for accuracy.