Motor won’t turn over – any suggestions?

[theiceman]

Originally Posted by elgyqc

You can always retime it. Not all that complicated IMHO.
Iceman has the right idea... you should be able to see if the cams are way off time.
Otherwise, I would loosen the sprockets on the end of the exhaust cams, effectively isolating the cams from the crankshaft. Turn the camshafts so that no lobes are pushing on valves... The engine should turn unless a valve is sticking into a cylinder or something is jammed in the valve chain system or in and around the crankshaft. If it turns, retime the camshafts one side at a time.
If you remove the cams while lobes are pushing on valves the camshaft will lift and that can be bad...
This should work... unless I have forgotten something.

i don't think there is any spot on either bank where no lobes are pushing on valves.. i guess OP will tell us.

[elgyqc]

Originally Posted by theiceman

i don't think there is any spot on either bank where no lobes are pushing on valves.. i guess OP will tell us.

There is... in this video at about the 3 min mark it is explained.
https://www.youtube.com/watch?v=xXfR60GAJd0&t=3s
If the engine is set properly there is no tension on the cams when the cam cover is removed.

[theiceman]

Originally Posted by elgyqc

There is... in this video at about the 3 min mark it is explained.
https://www.youtube.com/watch?v=xXfR60GAJd0&t=3s
If the engine is set properly there is no tension on the cams when the cam cover is removed.

im not sure why you think this .. it is minimized but not zero ... all he is showing is TDC for cylinder one .. has nothing to do with 2 or 3 . or tdc for 4 but 5 and 6 have valves out.

Ive done this job so i can tell you there isnt a spot where everything is tdc on the same bank with no valves open at all ..

the only reason there is no tension on the cover when it is removed its because you have to lock them down first .. it is NOT because where the valves are positioned.

[elgyqc]

Originally Posted by theiceman

im not sure why you think this .. it is minimized but not zero ... all he is showing is TDC for cylinder one .. has nothing to do with 2 or 3 . or tdc for 4 but 5 and 6 have valves out.

Ive done this job so i can tell you there isnt a spot where everything is tdc on the same bank with no valves open at all ..

the only reason there is no tension on the cover when it is removed its because you have to lock them down first .. it is NOT because where the valves are positioned.

Sorry but I disagree. On a four stroke engine the valves on each cylinder are closed half of the time, from the bottom of the intake stroke through the compression stroke to the bottom of the power stroke. So the cylinder doesn't have to be at TDC to have the valves closed. In fact on TDC of the exhaust stroke the exhaust valve(s) are closing and the intake valve(s) are opening. So as long as the three cylinders on a bank are between the start of the compression stroke and the end of the power stroke all valves are closed.
I have changed the tensioner pads on 3 engines, which doesn't make me and expert but permitted me to make the error of removing the cover when the engine was not properly aligned (in fact it was aligned for the opposite bank, not the one I was disassembling). When I took the cover off one of the camshafts rose about an inch at the end opposite the chain. When the engine is properly aligned the camshafts rise about a millimeter.