Timing Belt Tension Issues

Golfer · Jan 22, 2017

Let me start off by saying this is a 7 bolt timing belt job on an Evolution 2 (ce9a) block. I purchased all new oem dsm 7 bolt parts (timing belt, pulleys, auto tensioner, front case, etc) the only thing that remains from the evo motor is the tensioner arm and the engine mount (the only two things I could imagine causing a problem). So at first I tried tensioning the pulley per the manual, 2-3ft lbs or whatever it asks for, but every time Id go to tighten pulley bolt the pulley would move and mess up the tension. I tried fighting the resistance and broke the pin on the jay racing tensioning tool. Plan B was to use the crow bar trick and make sure the grenade pin moves freely after 15 min. Well that works, but I am not passing the drill bit test. When measured properly (drill bit parallel to surface of auto tensioner) its about 0.125" I can however get a 5/32" (0.156) drill bit in there but its at an angle (as seen in attached photo)

Does anyone know what is going on here? Should I buy a new tensioner arm? Am I over thinking this and should just leave it at 0.125 as long as the pin fits in there?

Thanks

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NB4G63T · Jan 23, 2017

If after you turn the engine over by hand 10-15 times, I forget the exact number, and if you can still slide the pin in and out you're good to go.

chrysler kid · Jan 23, 2017

You want to leave the pin in the hydraulic tensioner and have the long rod on the arm so when you set the tension your doing it only against the belt.

You would then remove the pin and the long rod for the arm and rotate the crank. After doing that the specified amount of times you check the tension with the drill bit or make sure the grenade pin can still slide back in

It can take a couple of times, the amount of tension on the pulley almost has to be done by feel and then double checked.

If the gap is too small you will hear tensioner arm hit the tensioner as a rattle noise or not at all and the belt will Whirr loudly.

Too loose and belt slack

Golfer · Jan 23, 2017

I guess that's my concern here. They are not one in the same. I pass the grenade pin test but I fail the drill bit test. Or if I pass the drill bit test, I'd fail the grenade pin test. Should I be worried that I don't pass or fail both? I thought they were supposed to result in the same gap.

chrysler kid said:
check the tension with the drill bit or make sure the grenade pin can still slide back in

1990TSIAWDTALON · Jan 23, 2017

If the grenade pin stays loose after spinning the engine over 6 times and letting it rest then I would be just fine with it. It is how I time my motors and haven't had a problem yet.

chrysler kid · Jan 23, 2017

1990TSIAWDTALON said:
If the grenade pin stays loose after spinning the engine over 6 times and letting it rest then I would be just fine with it. It is how I time my motors and haven't had a problem yet.

Correct. Typically the belt does expand very slightly after it has been through a few heat cycles. On a kevlar belt it can take up to a thousand miles, a typical oe style belt should just be a few hundred miles. (So the gap being slightly smaller is ok, minimum gap is grenade pin being able to slide in freely)

The hydraulic tensioner is designed for exactly that, otherwise if you could just insert the pin before doing a timing belt replacement you wouldn't need that extra long threaded tool to compress the arm down. So as a belt gets warn and old it does expand the gap on its own

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Timing Belt Tension Issues

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