3.5l timing belt tensioner-not to spec after torquing

[disco stu]

Hey guys. Doing the timing belt on new engine currently. I'm having trouble getting the tensioner pushrod to have the right protrusion after torquing the tensioner pulley (the one with the offset hole). Is supposed to be between 3.8-5mm. I'm down at around 2mm, there is no tension on the pin holding the rod in

Following instructions with kit and also workshop manual, the pulley has to be torqued counterclockwise, meaning the little holes hang below the bolt going through it.

Not having access to a backwards torque wrench (or one that goes so low either) I've e been using weight hanging off a lever to provide the torque-in this case 3.24lb hanging off a 1ft lever. After tightening bolt I rotate engine twice, wait and then check pushrod protrusion. Done this 3 times and no change each time-after waiting I can put the pin back without issue

I'm either doing something wrong, or there is no way of getting the torque right and pushrod sticking out that amount, either one or the other. Unless the pulley is meant to rotate around the other way and be torqued clockwise rather than anti clockwise.

Would appreciate any advice from you all on whether I'm doing something wrong etc

Thanks, Stu

[damo03]

Mate,

I am about to attempt this in a week or so after I have changed the valve stem seals and hydraulic lifters which I am doing next week. I have the timing belt exposed so can see what you are talking about.

Having not done this, but reading the manual this is how I interpret the instructions:

The two offset holes on the pulley that you put the torque wrench into need to be on the bottom of the pulley so that when you apply a counter clockwise torque, there is a little tension put on the pulley. This tension is a pre-tension so that when you release the pin on the hydraulic tensioner, the pin sticks out the correct distance to allow for movement over time etc.

You want to be rotating the tensioner puller in a anticlockwise motion from the two holes which are at the 6pm position of the pulley. This will apply a force into the belt (pre-tension). Apply this force in an anti clockwise direction then with a spanner lock off the bolt. You can torque the centre bolt up to 48Nm once you are happy you have the right tension set.

As a rough estimation, if you use a breaker bar that is 0.45meter long, and apply about 1kg of force anti clockwise on the two holes you will get 4.4Nm. As you an see this is not much weight to apply. If you weight 1litre of milk that's about 1kg so you can get an idea of how much weight you need to apply upwards to a breaker bar. It's barely anything. I would suggest forgetting hung weights and a torque wrench and try to apply the right torque by hand.

The check will be to rotate the engine clockwise with the pin on the tensioner released. If you have the right tension set by hand, then the tensioner will release the pin about the right amount.

Is it a new tensioner or are you re-using the old one? Perhaps the hydraulic tensioner is faulty?

[disco stu]

Cheers Damo. That is exactly how I interpreted the instructions also. Good to know I'm on the right track

I have a brand new tensioner. I haven't released it fully, but it is pushing out if I rotate the tensioner pulley a bit less. Maybe I'll check it to see if its in specs

I think your original reply mentioned that I might be applying force the wrong way, although it doesn't say that now. If its not clear, I'm applying the force in counterclockwise direction, just have the lever sticking out the other way so the weight is meaning it rotates the correct way.

Your estimation of 4.4nm seems pretty much what I've come up with, just that I'm using a bit heavier weight on a shorter lever.

Hydraulic tensioner-the manual shows oil pressure pushing into the tensioner, but there is no way oil can get into this one. Seems to me that it can only be spring pressure. I remember the toyota one on my camry was supposed to be oil pressure adjusted somehow as well, but it seemed to be pretty much exactly the same as this one-a sealed unit. Anyone shed any light on this?

So you think ignore the torque specs, rotate by hand and basically adjust for the right tensioner rod stick out? My ultimate question basically is what is more important-the pre applied torque or the tensioner rod stick out?

[disco stu]

This is picture out of the manual. It shows both holes below bolt (top and bottom pic) and holes above bolt (middle pic). I currently have holes below bolt.

I feel that it would likely meet specs better if the holes were above bolt, as in the middle picture, as that would change the leverage and angle a bit more allowing the hydraulic tensioner to push a bit harder.

Any opinions on that?

[disco stu]

This ones bothering me slightly as I don't want timing dramas. Did a bit more reading and came across this from Pauly Faulkner:

They face down and you rotate it counter clockwise to tension. If they face up then the pulley comes away from the centre of the engine as tensioner rod extends.

Put a large flathead between the pulley and the pulley arm and push handle of screwdriver towards passenger side to lever the pulley away from pulley arm until lock pin becomes a little loose and nip the bolt up while still holding screwdriver firmly. Rotate by hand once and come to a stop in a clockwise direction at TDC and repeat tension. Turn again and if lock pin still moves easily you're done and it can be removed.

Tool is not needed.

Doing this doesn't rotate it as far as the hanging weight perspective. The holes are basically inline with the auto tensioner. This means the rod sticks out a little further, but still not as far as the specs say. I was concerned about over tensioning the belt potentially leading to breakage, so this puts a bit less tension on it.

Whatever happened to timing chains?? Never really had any issues with those. Cost saving for manufacturers I assume

[damo03]

See the photo of mine in situ... as it has been for the last 90000km

[disco stu]

Thanks Damo. That photo is taken from above? Just checking I have perspective correct. Looks like water pump pulley there also. Just surprised as it shows the torque holes above the bolt

[damo03]

Yes photo taken from above and this is the existing belt before I've changed it. I'll get a better photo on Sunday night and give my opinion as I'll be doing the same thing in a week or so.

[tomwithannl]

damo03. Your tensioner has been turned the wrong way for at least 90000km
They should be turned anti clockwise from the 6 o'clock position so when the motor is running the belt tension is trying to turn the tensioner center clockwise helping to keep the locking bolt tight. The way yours is it is actually trying to undo the locking bolt due to the leverage of the eccentric tensioner center. Mine was the same when I put the Magna motor in years ago. It doesn't seem to be a problem 99% of the time but COULD cause grief so it should be the other way.
The picture in the manual (2nd down) is wrong and was brought up when I worked for an MM dealer.

Tom

[benckj]

I went through much the same drama when I installed a new belt and tensioner on my 3.8 NS. I found two different directions that contradicted which way to install tensioner. In the end I referenced my pre-install pics from factory and worked out that it was installed with holes on top meaning a clockwise torque. If I can locate I’ll share some pics along with the 2 install directions.

Been running engine for 20+k and no issues.

[disco stu]

Well-that's as clear as mud!! Mitsubishi dealer saying holes below bolt. Original timing belt with holes above.....no wonder I'm struggling

I like the reasoning given by Tom with the bolt being potentially loosened. It's just that doing what they say means some part of the specs aren't meet. As it is I've pre torqued less, meaning the tensioner rod sticks out more than before, but now to spec. I'm sure tension will be fine still given the tensioner is controlling that. I'll just stick with what I've got until I hear decent reason to change

Thanks for all the comments guys

[benckj]

Well-that's as clear as mud!! Mitsubishi dealer saying holes below bolt. Original timing belt with holes above.....no wonder I'm struggling

The difference may be due to the models (mine is 2006-NS). Logically, I thought the counter -clockwise rotation had to be correct due to the forces applied during timing belt rotation. When tightened in this fashion the tensioner bearing ended up very close to the crank gear and the specified tolerance for tensioner shaft was not achieved. Ran the engine in this configuration and it was obvious that the belt was loose. (ref first pic)

Once I tightened it clockwise the belt became tight, tolerances were achieved and the position matched factory configuration. Ran the engine like this and belt remained tight and further inspection after driving on road showed it remained unchanged. (ref last pic)

I'll leave the conclusion up to anyone reading this but I sympothise with your confusion as I've been there myself. Pics below for reference.

[disco stu]

Thanks for that. Must be quite a difference between models like you say, as my tensioner pulley doesn't end up anywhere near as close as what your does when tensioned anti clockwise. If I recall correctly, Damo's was on a Gen 3.

Intriguing that there is so much difference between cars with this one

[benckj]

Intriguing that there is so much difference between cars with this one

I think this is why I read contradicting directions for installing tensioner. The confusing bit is that the parts are near identical but the mounting location & geometry differ.

All the same hope you get sorted and are satisfied with the result as its a difficult enough job to complete. Because of this confusion I pulled mine back apart and changed it. Decided that running the engine and observing operation was the best way to confirm.

[disco stu]

Cheers. That's what I'm definitely trying to avoid-doing the job twice. Engine is out of car so its not a big issue to do at the moment.

Looking at the geometry, the way mine is currently, being tensioned counterclockwise, is about the same geometry as yours is now being tensioned clockwise. Makes me think that its alright as is, but..