Timing Belt Tensioner Torque

[GXCars]

I'm doing the belt on my sons caddy tomorrow with a 1.9 BLS engine

Done a few of these before with no issues so far...

I've opened up the INA kit today just to check I have everything, I pull out the leaflet with the tensioner, it says tigthen to 23nm +/- 3nm so anywhere between 20-26nm BUT then says tighten a further 45 degrees.

ELSA says 20nm plus 45 deg

I've always done these at a straight 23nm as it effectively is 20nm +45 deg, in theory this says I could go to 26nm +45 deg which I think is too tight as its effectively 20nm plus 90 degrees from my calculations

I always replace the studs on these and always buy either VW or INA kits as they come with a litens tensioner, not a nasty Dayco one with no studs and a Chinese tensioner...

Does anyone know if the torque settings have altered recently? - any wisdom appreciated

[Crasher]

Dayco is often fitted from the factory, I have NEVER had any issue with their products but then we only fit genuine kits from TPS which often I come with Dayco belts.

[tditaff]

I've just done mine (BXE), the engine mounting bracket bolts were a pain to get at!
According to the manual the stud is 15NM, the tensioner nut is 20 NM + 45 degrees.

[dekhelia]

Yeah, just recently done mine too (BKD). I got pretty nervous about the tightening torques, given the horror stories I'd come across about the stud snapping etc. Mine was also an INA kit, but I ended up taking out the stud as I became convinced I'd overdone it, and getting new studs (for the idler also) and nuts, and then buying a low-value torque wrench. I'm glad I did, although if I'm being rational and not superstitious the original effort might well have been fine. Anyway, I've just done a 400-mile trip up the A1 and back, and things haven't exploded.

Torque values I used for the tensioner were 15Nm for the stud, then 25Nm + 45 deg for the nut.

[Crasher]

We always replace both studs even if they don’t come in the kit. Certain models have a double sized stud, M10 into the head and M8 for the tensioner. The critical point with these is you must ensure the shoulder radius of the stud is below the surface of the head or else the tensioner will sit on the stud and it will fail, sometimes I have to tap the hole a little deeper to make sure it is recessed.

[dekhelia]

We always replace both studs even if they don’t come in the kit. Certain models have a double sized stud, M10 into the head and M8 for the tensioner. The critical point with these is you must ensure the shoulder radius of the stud is below the surface of the head or else the tensioner will sit on the stud and it will fail, sometimes I have to tap the hole a little deeper to make sure it is recessed.

This is making me slightly nervous. Why, exactly, does the stud have to be replaced? Surely if it's seated right and correctly torqued, there should be no need ... or is a matter of fatigue over time? I'm getting nervous because despite having just driven 400-odd miles at motorway speeds with my newly fitted cambelt and all the other associated parts, I can now hear a slight rattle from the area of the tensioner or perhaps the idler, which I'm sure wasn't there before. If it was going to go, would it have gone by now - or could it just happen at any time over the next few thousand miles?

The thing is, I only came across your post, Crasher, about the critical importance of having the tensioner face touching only the flat cylinder head, and not any part of the tensioner stud shoulder which may be protruding above this. Not being aware of that, I just didn't check it. It may be fine, but I just don't know. I've decided not to drive the car until I get the chance to check it.

Also, I've read since I started worrying, that many techs think that the tensioner and/or idler stud can only be replaced a couple of times before the cylinder head tap that accepts the stud loses its ability to 'hold' the thread; how true is this? And if true, is the only remedy to replace the stud with the M10/M8 part, as opposed to the M8/M8 one that I have?

I noticed also that while I was putting tension on the belt, I could get the pointer to line up in the right place with the notch in the back plate; but that the pointer tended to move to the right as I applied torque to the tensioner nut. Is this normal? I got around it by not tensioning it all the way to the notch, letting the nut, as it was torqued, move it the rest of the way. Now I'm wondering whether this phenomenon occurred because the tensioner is in fact touching the shoulder of the stud - d'you think this is possible?

Sorry for so many questions, but I would be gutted to wreck this motor after all the work I put in to change it...

[Crasher]

Let’s get it clear what you have, which engine and did you fit a new stud so I can get my head around this.

[dekhelia]

It's a BKD and yes, I did fit a new stud. Twice, in fact, as I thought I had over-torqued the first one.

[GXCars]

I agree Dayco belts are excellent quality its just the tensioners seem to have dipped in qiality since they moved away from Litens which is why I've stopped fitting them. My original question is the torque setting as INA seems to differ from the factory manual given that overtightening is just as bad as undertighting.

Some of the TPS kits didnt used to come with studs but I think all all do now and the few I did recently were all Contitech written on the belt who I believe own Dayco now but with INA rollers and Litens tensioners

[Crasher]

W"e only fit genuine kits, it is too much of a worry.