2007 V8 2UZ engine. Was very careful. Ensured new belt matched up with all marks after tension roller back engaged. Started hand rotating clockwise & I bump against some serious engine interference @ 1/8 to 1/4 1st revolution. I stopped. Reversed back to TDC. tried again slowly & hit hard stop @ same point. What could have happened? I made sure nothing moved from when the old belt came off & the new belt was installed. Rt Cam went slightly clockwise (toward driver side) when tensioner & original belt was removed. Left there, & installed mark on belt to correct sprocket tooth, & when tensioner reinstalled, as belt tightened, the cam rotated back counter clockwise to exactly the right position. But it locks against something when hand rotating. Any help would be greatly appreciated.
In trouble: Chg'd Timing belt & engine locks up when hand rotating
- Thread starter Psheehy
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03_4x4Runner
Senior Member
The cam position would have to have moved if a valve is hitting a piston. Are you sure you are not just coming up on compression stroke on one cylinder? Probably not with just 1/8 turn of the crank. Might be time to have a pro come look at it before you bend a valve. You did pull the pin on the tensioner didn't you? Other wise the belt could jump a tooth or 2.
toyotatech84
New member
if im not mistaken, isnt the 07 with the vvti gears? the previous poster does have a valid point. maybe the cam gears turned a 1/4 turn and causing you to hit the valves on the piston tops
Concerned @ hitting a valve, so that is why I stopped while rotating. Unsure if I am coming up on compression stroke, but all s.plugs are in. Removed tensioner pin properly, so it did not jump a tooth. Are valve clearances timed so close that being off by 1 or 2 teeth would put me into interference mode? But everything lined up perfectly after installing belt & putting tension back on it- all 3 marks (2 cams & crank sprocket). Line marks on new Toyota belt all match the sprocket marks.
The cam gear sprockets notch marks are in the same location now w/ new belt as they were w/ old belt. I had to back 1 cam gear up slightly while installing belt, & I did struggle greatly getting the crank bolt off- allowing the crank pulley with old belt still attached to rotate engine backward as much as 1/8 turn. But everything was lined up before removing belt & was still lined up after installing new belt.
The cam gear sprockets notch marks are in the same location now w/ new belt as they were w/ old belt. I had to back 1 cam gear up slightly while installing belt, & I did struggle greatly getting the crank bolt off- allowing the crank pulley with old belt still attached to rotate engine backward as much as 1/8 turn. But everything was lined up before removing belt & was still lined up after installing new belt.
progress4m
Member
I would recommend that too, also I do not believe being off by 1 or 2 teeth would put you into “interference” mode.
I pulled #1 plug. Didn't change anything by reducing some compression- still bump against something internal to the engine at the same spot every time. Tried CCW rotation and get same 1/8 to 1/4 crankshaft rotation & then hit hard against something internal. How much rotation would account for #1 cylinder to go from Top Dead Center to Bottom Dead center?
Went to Dealer to ask for ideas. They said I should be putting the two CAMS marks & belt marks on the yellow "T"on the timing belt rear cover? If I do that, the timing belt will have to shift, & the timing belt mark that currently aligns with the crankshaft sprocket marked tooth will no longer align.
Would rotating the crank w/o the timing belt, & then manually move the Cams an equal rotation a little at a time to try to see if I can pick up on what is hitting what make any sense? Do each Cam move 2x per 1 revolution of the crank pulley? because it always seems that you have to make two complete revolutions of the Crank to get Cams to align back to their marks on engines not having this problem. Thanks for any guidance you can send. I am stuck.
Went to Dealer to ask for ideas. They said I should be putting the two CAMS marks & belt marks on the yellow "T"on the timing belt rear cover? If I do that, the timing belt will have to shift, & the timing belt mark that currently aligns with the crankshaft sprocket marked tooth will no longer align.
Would rotating the crank w/o the timing belt, & then manually move the Cams an equal rotation a little at a time to try to see if I can pick up on what is hitting what make any sense? Do each Cam move 2x per 1 revolution of the crank pulley? because it always seems that you have to make two complete revolutions of the Crank to get Cams to align back to their marks on engines not having this problem. Thanks for any guidance you can send. I am stuck.
03_4x4Runner
Senior Member
I do not have any experience on how to get it back in time. I did my own timing belt but I had a freind with a lot of experience double check the belt timing marks for me before turning over the engine. I did not have to move the cams or anything. I would be carefull hitting the hard stop you describe as it would be easy to bend a valve. You may have to bite the bullet and pay a pro to look at it. I know it is frustrating but most here probably do not have enough experience to help you much. Maybe would could have a pro come over and look at it for a six pack of beer or something.
Your crank will turn twice for each time the cam rotates once. You have a compression stroke followed by the exhaust stroke. If you lined the marks up properly on the cams and the crank you shouldn't have an issue. There are marks on the belt and the pulleys that make the job pretty easy. As mentioned you can pull all the plugs to see if you are feeling compression during your rotation. Pulling 1 plug will not do anything because with 8 cylinders, you will have 4 in exhaust and 4 in various states of compression.
BlackWorksInc
New member
At this point, take the belt off and re time the engine, somewhere the teeth became misaligned, it is advised you do not turn an engine backwards of its rotation because it can cause slack on the belt and or chain enough to slip a tooth or when turned normally.
If I were having this issue in the shop (which I had doing a cylinder head on a Jeep Liberty) I would pull the belt or chain off and re time the engine to be sure. I'd rather spend the half hour to hour retiming the engine while its torn apart than have to tear it all down to do it again.
If I were having this issue in the shop (which I had doing a cylinder head on a Jeep Liberty) I would pull the belt or chain off and re time the engine to be sure. I'd rather spend the half hour to hour retiming the engine while its torn apart than have to tear it all down to do it again.
BlackWork is right. I've done about 5 t-belts and water pumps in my life, but have worked in the shop for years. This is what I would do:
- Remove all the plugs (just makes it easier to rotate the crank assembly)
- Remove the belt
- Make sure the cam gears are in the right positions
- Make sure the crank pulley is in the right position
- Put the belt back on and try again
- If still fail call a buddy that knows
- If continue to fail, get a flat bed and take it in. (no shame in that, happens)
- Remove all the plugs (just makes it easier to rotate the crank assembly)
- Remove the belt
- Make sure the cam gears are in the right positions
- Make sure the crank pulley is in the right position
- Put the belt back on and try again
- If still fail call a buddy that knows
- If continue to fail, get a flat bed and take it in. (no shame in that, happens)
Atlanta_man
New member
I'm sure this will have a happy ending (but please tell).
There's not supposed to be any magic or cam / crank phasing issue with this is there ?
There's not supposed to be any magic or cam / crank phasing issue with this is there ?
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