TDC issue - help needed please …

[Homeoboxter]

Originally Posted by JFP in PA

He only has the cams out of one bank, rotating the engine in this configuration is problematic.

Why would it be? The two chains are independent on each other and the other bank is intact with all the tensioners and chains I assume.

[blue62]

Wouldn't it pull the IMS (the shaft) out of alignment?????

[JFP in PA]

Originally Posted by blue62

Wouldn't it pull the IMS (the shaft) out of alignment?????

Only if the IMS rear flange were removed; if it is in place, the shaft cannot move.

[blue62]

Originally Posted by JFP in PA

Only if the IMS rear flange were removed; if it is in place, the shaft cannot move.

Thanks for the clarification. I had some vague memory of the shaft moving out of alignment when rotating the engine. If I would have thought for a moment I would have realized it could only happen with the rear flange removed.

[JFP in PA]

Originally Posted by Homeoboxter

Why would it be? They the two chains are independent on each other and the other bank is intact with all the tensioners and chains I assume.

Because I would be willing to bet if he has the cams out, he also has the tensioners out as well (it would be real interesting to try and remove the cams on one bank without releasing the tensioners), which means the remaining long chains are slack and potentially able to slip during rotation.

[Homeoboxter]

Originally Posted by JFP in PA

Because I would be willing to bet if he has the cams out, he also has the tensioners out as well (it would be real interesting to try and remove the cams on one bank without releasing the tensioners), which means the remaining long chains are slack and potentially able to slip during rotation.

I rebuilt the engine from scratch about a year ago and as far as I remember there are three tensioners in these engines, one for the crankshaft to IMS chain and one for each of the banks. For pulling the camshafts on one bank you only need to remove one tensioner that corresponds to that bank. The other bank has a separate one on the other side of the engine and that can be left intact. The two long chains corresponding to the two banks run on the opposite ends of the IMS, so it`s very hard to mess with the other bank`s chain. So you can even pull the entire head off on one side and still can rotate the crankshaft safely if everything else is intact on the other bank. Obviously you need to hold the chain so it won`t get stuck in the crankcase. If he removed both (or all three) tensioners, then yes, turning the crankshaft over can be problematic... But if he started with removing all tensioners for no reason without setting the timing I`m not sure he should proceed with this job..