I've just replaced that big idler pulley between the cams on my 1990 3vze and I think I've got the timing belt back the way it is supposed to be. I had originally held it in place with spring clamps, but then something shifted and I couldn't trust how I had it, so I checked it again. I set the timing mark on the crankshaft, set the timing marks on the cam pulleys, got as much slack as I could out, put in the tensioner and was going to check it all out by barring the engine when I realized I don't remember what I'm looking for, or if that's even the right way. My thinking was to roll the engine two revolutions and see if the timing marks on the belt align with the marks on the pulleys, then I thought it was different from that, like there's a migration of the timing marks on the pulleys and belt that I needed to check. I searched all over and apparently I'm using the wrong search terms because I can't find anything useful.

Can anyone help me with this?

ThanX
DC

 

There is migration of the belt position, but the cam pulleys should come back to their same marks after two revolutions of the crankshaft.

 

The marks on the belt are only there for convenience of installation. After you spin the crank twice, just look at the marks on the crank sprocket and cam sprockets. Don't worry about the marks on the belt; it actually takes over 100 turns before they come all the way back.

 

Awesome! ThanX guys!

 

Here is the tip on doing this correctly. It will get your belt tension correct and is the only way the FSM tells you to do it.
With the crank at TDC, remove the belt and the CAM pulleys and take out the dowel pins that key the pulleys to the CAM's.
Replace the CAM pulleys on the CAM's and thread the bolts in but leave them 1/4 turn from being snug so the pulley can spin on the CAM freely without turning the CAM shaft/s.
Install the new belt and lign-up the marks on the engine with the marks on the pully's. Don't worry were the CAMS are its not important so long as they are close to TDC.
Install the tension and spring and allow the tension-er to take out the slop. The tension-er needs to be able to rotate on the pin with the springs pull.
The belt marks and the engine marks and pully's should all be close to perfectly in alignment with each other at this point.
Then rotate the engine for several complete revolutions past TDC and get the belt well seated with the tension-er being spring loaded only.
Then secure the tension-er by torquing it's two fasteners. Yes the spring then does nothing from this point on.
Assuming everything was at TDC when it was removed bring the crank back to TDC.
Remove the CAM bolt/s and rotate the crank shaft back and forth until you can slide the dowel pin/s back into the pully's notch and CAM.
Reinstall the CAM bolts and torque to specification, very important!
The 3VZ-E is a non interference engine so you can do this all day long without fear of bending anything in the valve train
If you don't do it this way you will be fighting the valve springs and the lobes on the CAM shaft and that I promise you will screw up your tension setting!
The 3VZ-E timing belt is a monster of a belt and failing to use the spring loaded tension-er arm to set the belt tension will in all probability cause over tension and premature destruction of the tension-er pulley, the water pump and/or the idler pulley that is between the CAM pulley's or the belt its self will disintegrate. When the water pump goes the antifreeze will head down to the crank shaft pulley area and it will cause the belt to come apart if this is not addressed soon enough.
Ask my son how we know this?

 

This method sounds like it's limited to the "older" style spring tensioner. The more modern hydraulic tensioner has a more direct method of setting belt tension in one step: http://web.archive.org/web/201204051...67timingbe.pdf

I don't know which vehicles have the older style tensioner. My preferred dealer site claims the older style 13505-65020 "fits" years 1989-93, and the newer style 13540-65010 fits 1992-95. Some overlap?

 

Mine has the older style spring tensioner.

 

DrCreosote,
You are then a candidate for following the procedure I have outlined above. Good luck with the method. The one thing that helps a great deal is a tool that will hold the CAM pulley from turning while messing about with the machine screws that hold the pulley to the CAM. I welded some 3/8 rods to a steel disk I got from IMS and welded a bar to it for a handle. I hole sawed a large hole in the middle to allow the socket a place to access the machine screw. This tool has been used on a variety of CAM pulley's to facilitate this holding requirement.