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Spitfire Mk3 Camshaft Timing - Help!


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Has anyone had difficulties in setting camshaft timing on Mk 3 1300cc engine without timing marks on cam or crank gears?

I took my engine apart to overall the unit but failed to notice that both camshaft and crankshaft timing marks were missing on both gears. However, according to the manual the inlet valve on piston 1 should starts to open 25 degree BTDC and I have set the time to this setting. Now the engine starts but the ignition time is miles out and the engine is hunting and lacks power.

Does anyone know if I have done the right thing or is there a better way?



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Trying to set a "start of opening" angle is the wrong way.

The correct way to set the cam timing is in the WSM. You set the crank to TDC on No 1 and set the cam so that the valves on No 4 are "on the rock" - meaning that one is just closing and the other just opening. This is the No1 firing TDC. The hardest part of that process is correctly determining exact TDC.

Once you've set the cam, you will then need to adjust the ignition timing because the mesh with the distributor drive gear has probably been moved when you took the engine apart.

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