SET YOUR CAM TIMING

Perfect cam timing needs care and patience, but is worth getting right

10 Timing is everything

Fit a dial gauge to the top face of the block, with its pointer resting on No.1 piston. Rotate the crankshaft slowly back and forth until the piston is exactly at TDC, when the dial gauge neither rising nor falling.

11 Align the timing marks

Fit the chain around the sprockets so the punched timing marks on both sprockets align. Rotate the camshaft until its bolt holes align with the sprocket, press the sprocket into place. Recheck the marks.

12 Torque and lock bolts

Once the timing marks align perfectly, tighten the bolts securing the large sprocket to 24lb ft. Gently turn over the ears of the tab washers, locking the sprocket attachment bolts. Lightly oil the chain.

13 Oil thrower and gasket

Apply sealant to both sides of the timing cover gasket and press into place. Fit the oil thrower over the nose of the crankshaft, locating it on the Woodruff key with its raised edges facing outwards.

14 Fit the timing cover

Hold the tensioner blade back inside the cover until it has located correctly on the side of the timing chain.

Align the timing cover on the dowels and stud then press onto the gasket.

15 Bolt up the timing cover

Fit all the timing cover set screws, taking care to select the correct length one for each location.

Tighten to 16lb ft, or 10lb ft for those threaded directly into the front plate and sump sealing block.

16 Distributor drive gear

Oil the skew gear and drop into its mounting on the block, engaging it with the camshaft’s gear. The distributor’s drive slot is slightly off-centre and aligns just above the 3-9 o’clock position with No1 at TDC.

17 Check drive gear end float

Fit the distributor pedestal to the block with a single gasket. Use a large screwdriver engaged in the gear’s distributor drive slot to check for play, whch should be slight. If the gear is tight, add another gasket.

18 Fit cam followers

Coat the cam followers with assembly lube then slot each one into position down the pushrod chambers. This completes our build of the Spitfire’s ‘short engine’.