996 timing issue?

[skyaker]

So I just pulled the engine out of my 2003 911. I have searched forums with varying success as to what might have happened. What confuses me still is that this happened while it was not running. My 911 has around 60K miles and I pulled it into the garage one night after driving it around 20 miles with no noticeable performance issues and when I went to start it a couple of days later it cranked and made a bad knocking sound during idle, I immediately shut it off fearing my IMS bearing had let go and hoping to avoid further damage. About a month later I ordered an IMS bearing kit to replace the IMS bearing. I pulled the transmission and began to follow the instructions, however, when I turned the engine over by hand it will only turn about 120 degrees before I meet resistance in either direction before I cannot turn the engine anymore with reasonable force. It will almost get to the TDC timing mark and the cam slot on the driver's side is almost straight up and down but the passenger side is about 1-2 degrees from vertical (But I am not quite at TDC). I figured something is really wrong, so I decided to pull the engine so I could investigate further.
I pulled the IMS bearing to investigate if it had let go with the understanding that I will need to re-time the engine. The IMS bearing was in great shape, so that wasn't the issue. I used a borescope on all the cylinders and saw no sign of valve marks on pistons or bent valves, so I am hoping I got lucky. I pulled the filter and oil pan to check for signs of wear or damage and the engine was clean throughout.
So that leads me to where I am right now. What is the next best step? Many of the procedures begin with locking the engine at TDC. Is there a timing procedure from ground zero that doesn't require the crankshaft and camshafts to be locked in place, such as manually rotating the crank and cams to the right spot and re-tensioning? If so, I should be able to release the tension in all the chains to disassemble the timing system, cams, and valves/heads to check for damage.

[Van B.]

Originally Posted by skyaker

when I turned the engine over by hand it will only turn about 120 degrees before I meet resistance in either direction before I cannot turn the engine anymore with reasonable force.

Not being glib, but I think you know what’s wrong. You’re just holding out hope it could be something simple.

[JFP in PA]

Originally Posted by skyaker

I pulled the transmission and began to follow the instructions, however, when I turned the engine over by hand it will only turn about 120 degrees before I meet resistance in either direction before I cannot turn the engine anymore with reasonable force.

I pulled the IMS bearing to investigate if it had let go with the understanding that I will need to re-time the engine.

Is there a timing procedure from ground zero that doesn't require the crankshaft and camshafts to be locked in place, such as manually rotating the crank and cams to the right spot and re-tensioning?

Perfect example of what not to do:

1. The IMS is not going to prevent the engine from turning over, but many other things will.
2. Buying unnecessary expensive parts without actually knowing what is wrong, and for an engine that would fail an IMS retrofit pre-inspection anyway (cannot be rotated to TDC).
3. There is no way to correctly time this engine if it cannot be first put at TDC, and later rotated.

What you needed to do is drop the engine out and find out what is blocking it from rotating, which is most likely nothing good..................