Help! Timing Belt Tension - Toyota Nation Forum : Toyota Car and Truck Forums

jjanari · 03-28-2005, 07:09 AM

Hey guys,

I'm in the process of "re-doing" my timing belt. In other words, after the 1st install, I noticed that I was one tooth off (while the car ran somewhat rough at idle with a noticeable rattle, it ran fine in the higher RPMs). I drove it with 1 tooth off for at least 2,000 miles (I know, don't quit my day job). In any event, when I went to re-install the belt, I noticed that there is a lot more slack in the belt, such that I know it's not tensioned properly and will probably slip off upon start up since I believe it's that loose. On the original install, I only replaced the belt and tensioner spring, I didn't replace any pulleys. The only explanation I have is that the belt must be shot from being installed incorrectly the 1st time. However, the new belt I just bought seems to be essentially the same length as the old one. any ideas? thx.

-jimmy

rusty9 · 03-28-2005, 01:17 PM

the belt should have some play in it on the side facing towards the front of the car...right side if you are looking at the belt on the car. it should move about 1/2" left to right if you pull on it. if its too tight you get that high pitched whining noise.

also if its just 1 tooth off, you can always adjust the timing enough from the distributor if youve got a timing light.

jjanari · 03-28-2005, 06:06 PM

thanks for the reply. unfortunately, I think it's still too loose because I remember that it was fairly difficult to get it on the 1st time I installed it and afterwards, it had moderate tension as the manual requires. Now it's seems much too loose and, in fact, when turning the crank with my wrench, there are times when its tension feels correct, then it begins to slacken some as it rotates, and then tightens up again, etc., etc., so I'm thinking the belt is presumably no good.

amerikim · 03-28-2005, 06:58 PM

When turning the crank, are you by chance pressurizing the combustion chamber? Remove the plugs and see if that helps.If you are feeling tension that comes and goes, I am thinking compression. But if it's not then its the harder one, where something is not running true anymore. Belt would not display that tendency.
Also looseness in the belt is taken up by the belt tensioner. So I don't get it.
Hmm, better you do it over and get it right. Be one with the manual.
But thats just my humble opinion. Peace.

Bmaintz · 03-28-2005, 07:36 PM

Even a new belt will stretch somewhat, that is the purpose of the Tensior Spring Adjust.....
This is how you set the tension on a new or used belt...... Take off the inspection cover, loosen the Tensior Pulley bolt, turn the crank pulley clockwise a couple of reveloutions with a 1/2 inch rachet with proper size socket (removing the apark plugs will help), retighten Tensior Pulley bolt...... As long as your Tensior Pulley Spring is OK this should set the proper tension on the belt..... Bob

jjanari · 03-29-2005, 07:12 AM

thanks for the reply guys. to answer some questions: yes, I did remove the spark plugs to make turning the engine over easier. I also followed the instructions for tightening the pulley and installing the tensioner spring (again, the first time around, everything went fine, with the exception of being 1 tooth off). I'm thinking it may be the belt just because I took it off without putting any matchmarks on it (it has at least 2,000 miles on it) and just put it back on. I suspect they recommend putting the marks to take into account the stretching of the belt, so I'll probably just try a new belt and see how that works. I'll let you know.

Bmaintz · 03-29-2005, 07:50 PM

Let us know.... I had a '87 wagon that jumped a couple of teeth (no get & go but would idle & start), I rest the belt & put tension on it..... Started to develope a loud metalic "click' fro the belt area that was driving me crazy, turned out that the flywheel Damper bolt was a little loose.... I took a 21" pullover with the propper size socket & whacked with a ballpin hammer, solved the "Clicking".... Bob

88 LE · 03-30-2005, 02:01 AM

Quote:

Originally Posted by jjanari

I'm thinking it may be the belt just because I took it off without putting any matchmarks on it (it has at least 2,000 miles on it) and just put it back on. I suspect they recommend putting the marks to take into account the stretching of the belt, so I'll probably just try a new belt and see how that works.

The belt can be installed anyway you want, as long as the cam + crank is aligned.

Forget about putting matchmarks on the belt. The alignment marks you use are on the engine.

You didn't say which engine you have, but try the link below:

http://yotarepair.com/Timingbeltinstructions.html

jjanari · 03-30-2005, 08:44 AM

thanks for the replies. I've got the 5sfe (4 cylinder). It's now running fine. I ended up pulling the tensioner pulley back against spring tension (which I did during the first install) and tightening down temporarily. I then put the belt on and undid the pulley bolt so the spring could set tension and then retightened the tensioner. I didn't do this initially on the 2nd install because I was able to slip the belt on without doing it (whereas on the 1st install, I believe I had to pull the pulley all the way back against the spring just to get the belt to go on). In any event, the tension amount was correct and I had none of the slack I previously experienced when I turned the engine over by hand. thanks again, guys.