ATX Timing belt tensioner tear-down (pics soon)

[hawkeye18]

I just wanted to let everybody know that I took apart my ATX timing belt tensioner today to see how it failed... basically, the rubber seal at the top of the unit got old and hard, got a bunch of little cracks on the circumference, and over time wore matching grooves in the shaft of the tensioner body. This caused a thousand microscopic leaks around the edge of the gasket, and over time the fluid leaked out.

This means that in order to rehab the unit, I would have to hone out the cylinder, which is easier said than done - the diameter is less than 1". I'm thinking a dremel with a polishing wheel might work, but I'd be worried about maintaining a perfect circle. Do they make cylinder hones that small? Because if they did, that would be perfect. Then, one would have to find a seal that worked - or get one manufactured (they look a lot like valve stem seals, but with rubber on the outside too).

In short, it's not looking good for a home rehab. I'm gonna try the ol' rubber rejuvination trick (which of course I have forgotten, but I know is on here somewhere) and see if it'll hold fluid. I plan on using ATF as it's pretty darn close to the same viscosity, and it should handle heat just fine.

My wife took our camera to wisconsin with her, so I have no way of taking pics (save crappy cellphone pics - I'm not gonna do that to you guys), so I'm gonna have to take it to work, disassemble it again, and take pics there. So... it might be a day or two, but you can once and for all see how these darn things work.

 

[whiteguy3]

Looks like some great info. Definately a way to learn how the ATX owners can get some relief from these tensioners. I plan on just making my ATX more reliable and easier to fix by modifying an MTX tensioner. Shouldn't be all that difficult. Keep the info of the teardown coming though.

 

[shauncock]

Im in the same situation i have two 3.2 motors and one tensioner has scared cylinder walls and a bad seal. The other one looks good but when i took it apart i made a big mistake and didnt measure how much fluid was in there. Now im stuck in the garage untill i can find out how much fluid to add. Do you or anyone else know how much add.

 

[shauncock]

Im in the same situation i have two 3.2 motors and one tensioner has scared cylinder walls and a bad seal. The other one looks good but when i took it apart i made a big mistake and didnt measure how much fluid was in there. Now im stuck in the garage untill i can find out how much fluid to add. Do you or anyone else know how much add.

 

[pccorrig1]

Just got a rebuilt from NESHO.COM late yesterday. Thanks Kirk! Had everything back together before the rain came. Initial reaction: it is so nice not to hear that below 2K noise anymore.

Regretably, I don't have a video camera, as I was running the engine without accessory drive or TB belt covers for brief periods, and it was interesting to see what was actually happening.