Toyota Repair: 1995 Camry Engine Mystery, crank shaft, mystery question

Question
QUESTION: Hello,

I have a 1995 Camry that was in a front end collision (with airbags deployed) after which the engine did run, and I was able to drive it a short distance into my driveway from where the tow truck dropped it on the street in front of my house. The next day I decided to find another Camry with a good body (but with a blown engine) to swap my engine into, instead of trying to fix the extensive front-end damage.

The day after the accident I went out to move it into the garage, but after one revolution of the engine, it stopped turning, and made a hard metallic sound. Since then I can only rotate the engine from the crank shaft pulley nut about 2/3rd's revolution in both directions, before something blocks it from rotating any further.

The car is a 1995 Camry, 4 cylinder, automatic with 137,000 miles, air, power windows, power sunroof, etc., well maintained, one owner, and driven daily until the crash.

The problem is, that after eliminating the most obvious potential causes, and then checking the not-so-obvious ones, and finally looking into some more obscure possibilities, such as: a dropped valve (compression is good on all cylinders, cams removed), or the starter ring binding on the starter gear (starter removed), there doesn't seem to be anything left to check that could mechanically interfere with the rotation of the engine. The oil pan and oil pump was removed for visual inspection of the rods, pistons, etc., and nothing can be seen interfering with these parts. Also, all belts are off and the water and fuel pumps can be rotated freely.

So I open it up to you and your readers to give me some  direction as to how I should proceed or what test to perform that successfully resolves this issue.

Donations: If it turns out to be a simple fix that would have saved me three weeks of disassembly and frustration, and the expert calls it out immediately, $20 bucks. If a reader has seen this before and provides the solution, $10. And for a real head-scratcher that the expert resolves through two or three follow-up tests or questions, and I don't look too dumb, since no one else seemed to be able to figure it out, I will donate $35 and declare Ted Ritter "The Master".    

Thank you for helping me solve this mystery,
JL
P.S. $10 donation made to show good faith (minimum from above list of donation amounts).

ANSWER: Hello, thank you for the donation,
Is this a 4 cylinder or V6 engine?
You say the compression is good with the cams removed, is this correct, how did you verify this?
Can you rotate the engine with the spark plugs removed?
In what state of disassembly is the engine now?

---------- FOLLOW-UP ----------

QUESTION: Thank you for your reply.

Follow-up questions:
1) Is this a 4 cylinder or V6 engine?
2) You say the compression is good with the cams removed, is this correct, how did you verify this?
3) Can you rotate the engine with the spark plugs removed?
4) In what state of disassembly is the engine now?

Follow-up answers:
1) It is a 4 cylinder engine
2) Yes, it is correct. I placed my finger over the spark plug hole and rotated the engine through approx. 240 degrees. There was pressure and suction at each spark plug hole, depending on whether the engine was turned clockwise or counter clockwise.
3) Yes.
4) Engine is moderately disassembled as it was not re-assembled between troubleshooting steps. Approximate order of tests to determine problem:

1) Timing belt removed to check valve timing (it was correct).
2) Starter pulled to check for starting gear and starter ring interference (there was none).
3) Pulled valve cover for visual inspection (cams appear ok).
4) Cams removed to isolate problem between upper and lower block components (interference to engine rotating through complete cycle remains.
5) Cannot be rotated past +/- 240 degrees rotation).
6) Oil pan and oil pump removed to check for possible foreign object in lower block area (no foreign objects found, nothing seen that might interfere between crankshaft, rods, or cylinder walls).
7) Observed each cylinder as crankshaft was turned within limited range of motion (no interference between lower engine components observed, all rods connected to pistons, no cracks in block or pistons observed, rods do not appear to be bent).

Step #8 is to ask for help on-line. I appreciate the time you are taking to help me with this.

Hopefully I'll be able to get the engine running without too much trouble, and find a good chassis for it.

Joel

Answer
Thanks for the reply. You have already done a lot of work and the engine is partially disassembled so why not remove the cylinder head for closer inspection, there has to be something that keeps the engine from rotating. With the cams removed did you check each valve closely to make sure they are all closed? If you can locate a "borescope" which lets you actually look into the cylinders you may consider doing that, some autoparts stores may have one you can rent.
The fact that you can rotate the engine about 240degrees would indicate that one of the pistons is hitting something near the top of the stroke.