Help - engine jams when turning by hand.

[aussiepage]

OK - I have repleaced a timing belt on our other car before but I am stuck.

I am in the process or replacing timing belt in a 1994 3VZ-FE with auto transmission. The car was running before I started the procedure. I have removed timing belt covers, inlet manifold and spark plugs. When I try turning engine by hand (starting from TDC) it turns approximatel 180 degrees (on brive shaft) before jamming.

Amazing - I have not even removed the old belt yet!

I am at a loss. I do not think I have dropped anyting into spark plug or inlent manifold and I alway tried to turn engine clockwise but was forced to back off to see if I can unjam engine.

Any ideas?? Could it be the transmiossion stopping me moving engine?

Many thanks.

[frenum49]

Originally Posted by aussiepage

OK - I have repleaced a timing belt on our other car before but I am stuck.

I am in the process or replacing timing belt in a 1994 3VZ-FE with auto transmission. The car was running before I started the procedure. I have removed timing belt covers, inlet manifold and spark plugs. When I try turning engine by hand (starting from TDC) it turns approximatel 180 degrees (on brive shaft) before jamming.

Amazing - I have not even removed the old belt yet!

I am at a loss. I do not think I have dropped anyting into spark plug or inlent manifold and I alway tried to turn engine clockwise but was forced to back off to see if I can unjam engine.


Any ideas?? Could it be the transmiossion stopping me moving engine?

Many thanks.

Deja-Vu. Didnt we just have someone with this same problem on 5SFE not too long ago? Anyway.
3VZ-FE engines are non-interference engines, meaning that even if you install the timing belt incorrectly the valves will not bottom out on the pistons. Are you sure this is a 3VZ and not a 1MZ-FE2? 1MZ-FE2's are interference engines. Since you have the plugs out it cant be just compression. I assume you havent loosened any torque converter bolts? Had the starter off of it? If so make sure there is nothing in the bellhousing jamming the flywheel. Make sure there isnt something floating around inside the timing cover jamming the belt. If you are sure yours is a 3VZ there is nothing left but to check the cylinders incase you dropped something down one of the spark-plug holes.

[aussiepage]

Thanks for your help. I have not removed starter motor. I suspect something must have dropped into one of the cylinders. I know piston number 3 is in it's compression cyle when it jams so will look there first. Hope I can resolve this today.

Thanks

[aussiepage]

OK problem not solved but is is not jamming anymore - do not understand why. Here is what I did today:-

1. Removed old timing belt and confirmed both overhed cam crack can rotate freely - no interference as expected.
2. Tried turning main engine shaft and it jammed with cyinders 3 and 6 at top. Always jammed in same spot.
3. Tried compresses air vacumm cleaner, magnet, wire etc to see if I could find something dropped in cylinder - nothing all day. Even rigged up a small white LED to drop into each cylinder so could see well.
4. Then for no explained reason the jam cleared and engine turns freely.
5. Again looked for something in cylinders but nothing.
6. Used a big electric drill to turn the motor over many times and as fast as possible.
7. After 50 to 100 turns - still no jam or any sound of something dropped into plug hole.
8. Not sure what to do now. Suspect someting may have been jamming flywheel but is is strange that it always jammed at same point.
9. Checked all torque converter bolts and they are tight.

Am confused. Is there any way for the gearbox or starter motor to cause this jamming? Any issue if engine is not supported when RH engine mount is removed. You can see I am clutching at straws here.


Once again thanks for any advice.

[frenum49]

Its a mystery buddy. Cross your fingers on this one.