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Loose timing belt

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triggerx

10+ Year Contributor
364
9
Aug 15, 2009
Gilbert, Arizona
Just did this timing job after a small rebuild on my 1g 90 talon awd, the tension was fine earlier,but seemed to have loosened up quite a bit?

I just replaced this hydrolic tensioner, so IDK if thats really it. Had it pushed in for awhile though
 
Did you set the initial tension correctly? What did you have for clearance between the tensioner body and the tensioner arm? Should be somewhere around 4mm if I remember correctly.
 
Definitely consider the above, especially since it's a fresh timing job, but also know that over time (hours) some slack will develop between the cam gears.

Are you running the engine or is it still on jacks?
 
The belt will lose tension between cam gears while sitting. Turn the engine by hand until the timing marks line up. Then check tension on all sides of the belt. If there is still some slack (more than 1/2" deflection), something isn't right with the tensioner or tension pulley.
 
That could be my problem, I didnt even know I had to set an initial tension, I just replaced the tensioner and thats it. It tightened up, and was good for awhile but seemed to have loosened. Ill check though.
Its just a PITA pulling off the lower timing cover. Literally takes longer than the the timing itself.

Its not on Jacks btw, I drove it for a good 20 minutes.
 
Will do, yea ### basically so far I know that there was too much slack between the cam gears. I turned the crank by hand and the slipped seemed to disappear. Well at least from the top.

See I had no idea I needed to mess with the tensioner. I mean I replaced it but I assumed it all tightened up automatically. And I didn't even loosen the tensioner pulley because I wasn't going to replace it.

But basically you all are saying that installing a new tensioner requires you to set it as well?
 
YES! You absolutely must preload the tension on the belt BEFORE you pull the grenade pin on the hydraulic tensioner. If you don't, at any time the tensioner plunger could bottom out and you WILL skip timing!
Please don't run the motor! You are lucky as hell you don't need a new cylinder head.
 
Setting the tension is a real pain in the a$$. Brain and I went through it yesterday on my Spyder. You have to go very slowly when applying or removing tension from the pulley. You'll want to make very small movements and wait about 20 seconds and keep checking the pin. Once you have it where you want, tighten the tensioner bolt while being very careful not to change the tension. It really helps to have two people for this as I'm not even sure you could do it by yourself. I've never tried, so I can't say for sure.

You're going to have to remove the tensioner and compress it in a vice. Go very slowly when you compress the piston. Tighten the vice, wait 30 seconds for the piston to compress and then tighten again. Repeat that process until you can put the pin back in the tensioner.
 
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