1G Timing belt tension procedure

[SnP9000]

I'm back yet again for the 10th time on this timing belt job on the 92 Eclipse GS 2.0 n/a

Between the nice set of special tools I bought for this job, the FSM page below, my Hanes manual and the thread below, I cannot get this belt tensioned according to the book.

I'm mistake prone but I wrench a lot and I'm not a dummy.
I have a very small torque wrench that can do the tiny tensioner tq.
I hold the tensioner pulley right on the wrench click and tighten the bolt with a 2nd wrench. No matter what, I get less than 2mm of tensioner stub protruding. Well short of the FSM spec.
I have tried intentionally making it looser to meet the spec and the belt was obviously not tight enough. No go.
The thread below says to set the tension such that the pin pulls out easily. Tried that, pin came out, still less than the spec.

Is this a problem (or difference vs OEM) with this Dayco tensioner? Am I doing something wrong I'm not seeing? Am I paying to much attention to this and just need to do the tiny torque and clamp it and be done? Am I in a movie?

https://www.dsmtuners.com/threads/timing-belt-tensioning-tips-for-4g63-turbo.214625/

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[steve]

I cheat.

I get the belt on making sure all the timing marks are correct and then go to tension the belt taking up the left over slack between the crank and the exhaust sprockets with the tensioner pulley. I use the pinned tensioner tool to rotate the pulley until I can freely slide the auto-tensioner pin and while holding it in that place tighten the bolt.

I wait a bit to see if anything moves and adjust if needed. Then I rotate the crank 6 turns until all the marks line up again and wait 15 mins. If the pin still moves freely I make sure all the bolts are torqued, check the pin one more time and pull it if everything it still good.

If your tensioner arm has any wear on it, from the pin riding on it, trying to measure the clearance between the arm and top of the auto-tensioner won't be correct. The factory spec assumes/requires a fresh tensioner arm.

 

[SnP9000]

This engine is all original with almost 180k miles on it, but other than a shiny spot on the tensioner arm where the auto tensioner bears on it, the arm itself doesn't have any apparent wear.

I have also done the "cheat" like setting the pulley so I can easily remove the pin. I did it again last night just before posting this thread. I was able to set the tension (which looks and feels good in the belt) and remove the pin by hand. The auto tensioner stub is just mostly packed into the tensioner housing still which I just don't understand. It sounds like everything is supposed to relax or settle out and the tensioner should extend or something. Is this protrusion spec a super critical thing?

 

[steve]

The procedure calls for you spreading the tension across the belt by you turning the crank over 6 times and then letting everything relax before you check the tensioner again.

It is a critical adjustment because while the engine is running the dynamic forces will change and the tensioner pin will extend and contract to keep the belt under a constant tension so you don't skip teeth or overstress the belt and everything attached to it. You don't want the arm to bottom out and hit the tensioner causing a spike in tension or extend the pin to it's limit where the belt is now loose.

 

[pauleyman]

This engine is all original with almost 180k miles on it, but other than a shiny spot on the tensioner arm where the auto tensioner bears on it, the arm itself doesn't have any apparent wear.

I have also done the "cheat" like setting the pulley so I can easily remove the pin. I did it again last night just before posting this thread. I was able to set the tension (which looks and feels good in the belt) and remove the pin by hand. The auto tensioner stub is just mostly packed into the tensioner housing still which I just don't understand. It sounds like everything is supposed to relax or settle out and the tensioner should extend or something. Is this protrusion spec a super critical thing?

We have argued about this on forums for awhile. Many of us use the pin method and you are correct if the pin slides the tensioner is on the tight side. For what it's worth I've been doing this method for about 20 years. I no longer measure the actual protrusion. If pin slides after 6 rotations, I'm done.

 

[SnP9000]

Yeah that was my fear the belt tension would go up under load and press the arm into the housing. The first day I tried getting the tension right I ran the belt 6 times and found everything still perfectly in time, I let it sit all evening through the next day and checked it after work. The tensioner had not changed. So last night I set it as I was able to remove the pin by hand and ran the belt 6 times around again. I assume when I get home it will not have moved but I will report back.
My coworker has built a lot of rotary engines and suggested I borrow his beam type wrench instead of my small clicker. Not sure this will help but I will give it a try if I need to do something different.

We have argued about this on forums for awhile. Many of us use the pin method and you are correct if the pin slides the tensioner is on the tight side. For what it's worth I've been doing this method for about 20 years. I no longer measure the actual protrusion. If pin slides after 6 rotations, I'm done.

Mmm interesting and noted...

 

[pauleyman]

Yeah that was my fear the belt tension would go up under load and press the arm into the housing. The first day I tried getting the tension right I ran the belt 6 times and found everything still perfectly in time, I let it sit all evening through the next day and checked it after work. The tensioner had not changed. So last night I set it as I was able to remove the pin by hand and ran the belt 6 times around again. I assume when I get home it will not have moved but I will report back.
My coworker has built a lot of rotary engines and suggested I borrow his beam type wrench instead of my small clicker. Not sure this will help but I will give it a try if I need to do something different.


Mmm interesting and noted...

Fwiw in 20 years I've also never noticed evidence of the arm hitting the tensioner.

 

[danl]

My coworker has built a lot of rotary engines and suggested I borrow his beam type wrench instead of my small clicker. Not sure this will help but I will give it a try if I need to do something different.

Use a beam type torque wrench if you want to do it by the manual. I’m not sure how a clicker wrench would work, seems to me it should not work. After using the beam wrench, you will develop a feel and can do it by hand.

Fwiw in 20 years I've also never noticed evidence of the arm hitting the tensioner.

I have only seen it when they fail.