Auto-Tensioner Gap

[dantesdoom]

I have gotten everything with the timing belt back together and i apologize for creating another thread, but i need to get this answered because of all the varied opinions i have gotten. I set the autotensioner on the belt with a 4mm gap. After rotating the motor 4 times, the gap is a little above three. I just dont see how there is enough play in it to unbolt and reset to get it right. I also havent been out to check it today, i have heard it expands back out some overnight?? Some say the spec is 3-4, some say it doesnt matter. I believe it does. Tell me whats up.

Where should the belt sit on the gears...front, back, middle? Mine are at the front

Now that the motor has turned, the lines on the belt dont match up on the gears and i was told they wont for a number of rotations. My dad wants to check behind me....is the only way for him to do it to count teeth at this point?

[nissanfreak12]

Ideally you want the belt to sit in the middle, but after running the engine, it will sit where it sits on its own. Just make sure both washers are on the crank pulley and you will be fine.

The auto-tensioner, the reason you want it about 4mm is for play in the belt. If its at 0, you have a great chance on snapping and/or prematurely stretching the belt. If it is higher than the spec, the belt will stretch like it suppose to and eventually the auto-tensioner will not be able to press against the belt, keeping it snug, and it could fall off. So setting it at 4mm, or in your case a little less, is ok. A little wiggle room is ok. If it was set at less than 3mm or more than 5mm, I would say redo it, but between 3-4mm is good enough. That means the tensioner is doing its job.

About it being correct timing, yes count the teeth. set the engine at TDC, make sure the dimples are on top and count away. If they dont match, recount to make sure you didnt make a counting error. If any of them are off, redo it plain and simple. The hardest one to count is the exhaust cam to the crank pulley. The way I did it was mark every tenth cog with a white marker. Remember, before you start up, rotate the engine by hand a few revolutions, any resistance, do not push through, it may be hitting the valve.

[dantesdoom]

Ideally you want the belt to sit in the middle, but after running the engine, it will sit where it sits on its own. Just make sure both washers are on the crank pulley and you will be fine.

The auto-tensioner, the reason you want it about 4mm is for play in the belt. If its at 0, you have a great chance on snapping and/or prematurely stretching the belt. If it is higher than the spec, the belt will stretch like it suppose to and eventually the auto-tensioner will not be able to press against the belt, keeping it snug, and it could fall off. So setting it at 4mm, or in your case a little less, is ok. A little wiggle room is ok. If it was set at less than 3mm or more than 5mm, I would say redo it, but between 3-4mm is good enough. That means the tensioner is doing its job.

About it being correct timing, yes count the teeth. set the engine at TDC, make sure the dimples are on top and count away. If they dont match, recount to make sure you didnt make a counting error. If any of them are off, redo it plain and simple. The hardest one to count is the exhaust cam to the crank pulley. The way I did it was mark every tenth cog with a white marker. Remember, before you start up, rotate the engine by hand a few revolutions, any resistance, do not push through, it may be hitting the valve.

Both washers on the crank pulley? you mean the ones on both sides of the crank gear....the one behin it and then the front one behind the crank pulley.....they are goldish in color?

[nissanfreak12]

Thats them, make sure you also have them where the washer bends away from the t-belt, that is what helps it keep it in line.

[dantesdoom]

so im confident about other everything than the tensioner....the book says 4mm, but since its an autotensioner...then it should be keeping the belt correct all the time. When i took the old one off....it had given out and fully closed up and it ran fine....but a lot of people keep removing and resetting. I think i might just leave it at 3.25 and call it quits

[dantesdoom]

or would that be foolish?

[nissanfreak12]

Should be fine, most people will not tell you a direct answer cause they don't want to be held responsible if it fails. 3.25mm is close enough to the proper amount cause it still gives it enough adjust properly.

Mine was set at 3.5mm and it is working flawlessly, I have checked it and it moved out to just over 4mm after 2k miles.

[dantesdoom]

Should be fine, most people will not tell you a direct answer cause they don't want to be held responsible if it fails. 3.25mm is close enough to the proper amount cause it still gives it enough adjust properly.

Mine was set at 3.5mm and it is working flawlessly, I have checked it and it moved out to just over 4mm after 2k miles.

kinda what i was thinking....the autotensioner that came off was completely collapsed....and it was fine....i think after the belt stretches some it will get into spec....i know the nissan techs just slap it on and call it quits because it IS and autotensioner for Gods sake.

[nissanfreak12]

Now get the car together and start driving it!!

[es.biggs]

Lol not to rain on anybody's parade, but I set the tension wrong on my z and the belt slipped and engine kaboomed. It's not something you just slap on and go...that's what I figured too but no.

[dantesdoom]

well the gap was @ 3.25ish .....but its back together now....would have been good to know earlier

[nissanfreak12]

I agree with biggs, its not something you just slap on, but dante you are so so close to that 4mm, you will be fine. If you are that worried about it, take it to a nissan mechanic. Just take it easy for a while, don't do any crazy high rpm's, maybe even let it idle with the covers off to see how the belt reacts. It will make you feel better.

[dantesdoom]

well its not something i just slapped on...i spent a good deal of timing measuring the gap.....when i put it on it was at 4....but when the belt pressed against it, it collapsed to 0. After i turned the motor by hand it came back up to 3.5. After sitting a little while it settled to 3.25. My thought was that after the belt turns a little, the tensioner will come closer to the 4mm mark as the hydraulic arm gets more pressure behind it and the belt settles in. Im not overly worried as the old tensioner leaked all the fluid out and i drove on it for 4000 miles with NO gap that and the deflection on the belt was already tight as it called for when the new autotensioner. Ill put it this way....no Nissan mechanic is going to finagle the thing until it reached 4mm, they will slap it on and take less care than I did. If the damn belt is that peculiar to less than one mm, the whole setup is a piece of s***, lets be honest.

[es.biggs]

Lol you should be ok man. Good luck

[nissanfreak12]

See biggs, look what you started, LOL!

Dante, to be honest, I stressed about the timing belt the first time I did it, just cause it is very intimidating. But your right about it letting you give a little play, just take it easy for it a bit.