These instructions are for the short stroke engine (post 1966) but the procedure is the same for the earlier models, only the settings differ.
(For the pre 1966 long stroke engine the valve clearances must be set with the engine cold and should be 0.2mm (.008”) on the inlet valves and 0.25mm (.010”) on the exhaust valves.)
Before you start you may wish to have a new rocker cover gasket and set of spark plug tube seals to hand as these can go hard with age and if so, will leak when refitted. It is bad practice and a bit of a bodge to use sealant on these gaskets.
Firstly it is recommended that the valve clearances (tappets) are set when the engine is warm, except on fuel injected engines when they should be set cold. Carburettor fed engines can be set cold too, if necessary, and both settings are provided below.
With engine warm, set clearances to 0.2mm (.008”) on the inlet valves and 0.25mm (.010”) on the exhaust valves.
With the engine cold, set clearances to 0.15mm (.006”) on the inlet valves and 0.2mm (.008”) on the exhaust valves.
- Turn the engine using the crank handle or by jacking up one front wheel and supporting it securely, putting the car in top gear and then turning the wheel forward to turn the engine. Always turn the engine in the normal direction of rotation (clockwise when viewed from the front). You can remove the spark plugs if you wish to make it easier to turn the engine. Turn the engine until number 1 exhaust valve is fully open (all the way down but not starting to come up again).
- You are now ready to adjust the valve clearances on inlet valve number 3 and exhaust valve number 4. To adjust the clearance, loosen the lock nut and slide your feeler gauge of the appropriate thickness between the top of the valve and the rocker arm. Adjust the screw until the feeler gauge blade is a firm sliding fit in the gap, then tighten the lock nut whilst holding the screw to stop it moving.
- Once the nut is tight, recheck the clearance.
- Repeat procedure for the next valve. Once you have done both valves, turn the engine until number 3 exhaust valve is fully open and set the clearances on Inlet number 4 and exhaust number 2.
- Once you have done both those valves, turn engine until number 4 exhaust valve is fully open and set the clearances on Inlet number 2 and exhaust number 1.
- Once you have done both those valves, turn engine until number 2 exhaust valve is fully open and set the clearances on Inlet number 1 and exhaust number 3
The job is now done and you can refit the rocker cover and spark plugs and put the car back on its wheels if you jacked it up earlier.