1850 engine rotation. Camshaft off.

[MIG Wielder]

Does anyone have a figure for how far the 1850 engine can be rotated from TDC (with the cam-shaft disconnected) before pistons hit valves please ? For instance if the engine was at the 8 o' clock position ( or 120 degrees BTDC ) would that be a problem ?
Thanks,
Tony.

[tony g]

Not the answer you asked sorry but if you need to rotate the crank fully for some reason, you could undo the cam caps a few turns and allow the open valves to close a few mm. It should clear then. Why are you rotating ?

Tony

[Carledo]

By the nature of the engine design, the camshaft at rest will have 2 valves open, 1 inlet and 1 exhaust. and one will be on one of the end cylinders (1 or 4) and the other will be on one of the middle cylinders (2 or 3) so the distance the crank can travel with cam stationary is say from cyl 1 just after tdc to cyl 3 just before tdc, or a few degrees shy of 180 degrees total movement without contact. This will work the same no matter what position the cam stops in, but clockwise or anticlockwise proportions from the start point will vary.

HTH Steve