Set-up is straightforward. Jack one wheel up off the ground, using a trolley or small scissor jack positioned under the subframe on one side (nearside/left is best). Then remove the spark plugs, engage second gear, and we’re ready to get busy! Once you have worked out what the cam timing is, adjusting it is dependent on what sort of cam drive kit you have. But no matter if it’s entirely standard right through to a belt drive kit – all can be sorted with the engine in the car. Removal of the radiator and engine mounting bracket will be needed at the most basic level, but that’s still reasonably easy. Standard and/or non-adjustable cam gears will require offset cam keys to correct the timing, while adjustable ones will either need a dowel pin moving or the clamping screws undoing then retightening.
The TDC indicator works by having a sliding centre rod, which is radiused at the end that contacts the piston, moving the rod up and down in the outer sleeve. It is entirely feasible to make one out of an old spark plug and metal rod. But finding a piece of metal rod of a suitable diameter and having the facility to properly radius the end so it moves smoothly on the piston crown is surprisingly difficult to deal with. At £8.00 plus VAT buying one doesn’t hurt the wallet too much.
The essential equipment required: A DTI gauge, top dead centre indicator, set of feeler blades and, for ease, a steel plate thick enough to support the DTI solidly. The steel plate is not essential; with the heater tap and studs removed the DTI magnetic stand can sit on the head if it is compact enough. Total value of these all bought new is around £30 – well worth the investment.
Get it as centred and as straight to the rod as possible with enough preload on the DTI spindle to cope with indicating TDC, and some way either side of that. You need to be aware that the architecture of some piston crowns may cause the rod to jam up when going well past TDC and back again. Simply hold the rod up when traversing these areas.
Fit the TDC indicator in number four spark plug hole, then fit the steel plate to the end head stud. Fit the DTI stand to that and position the DTI spindle tip against the top end of the TDC indicator rod.
With number one piston at TDC and the rockers on the overlap (rockers rocking between inlet and exhaust overlap), undo the adjuster screw lock nuts.
Unscrew the adjuster screws all the way so that the valves close completely on both inlet and exhaust.