Cam belt a tooth out?

I have done a few belts on a couple of different makes of engine, few of them lined up exactly the way they were supposed to. Always close but rarely spot on. We always forget to check the timing marks before we take the belt off (well...I forget to check). This is more relevant to engines with timing marks rather than pins.

However, while it was hard to tell if it was right, it was easy to tell when it was wrong. One way is always much closer than the other options. This is why you must recheck the tension and alignment after turning the engine over at least 2 times (twice is one cycle). You need to check that the belt "settles" into the correct position and tension.

It is not important that the lines on the belt line up but it is a sort-of double check that you have got things right. In fact most brands of belts only have the direction marked and some, not even that.

While setting the timing is important, I might argue that the correct tension is critical. So ensure the pointer lines up with the notch during the tensioning process and when you are finished.

hi, just had another go (4 to be precise) trying to get the tension right.
I looked at taking the 8mm drill bit out and moving the cam down but it would be a hole rib on the belt, there's no way i could get more tension between the cam and crank so I followed the tensioning instructions, locking cam and flywheel, I put the pin back into the tensioner but it made the belt very slack so I tensioned belt till arrow was in the notch, turned engine over 4x, lined up the cam and crank., locked them off, put it back together, it was on axle stands so I put it into first and it reved quite well so lowered it and drove it. It seemed better than before but still needs a lot more reving in 1st, so still not the original timing.
I checked the tensioner again and had found it had moved up 5mm so I readjusted it and put it back together, tried it out and still the same.
I feel like tensioning it more as it feels that may help. I'll try again tomorrow. I'm now doing it without taking the wheel, aux belt off which is making it somewhat faster.....
What do you reckon?
Appreciated...

some photos of my van not go...
sorry about the order, never posted pics before and 'm struggling here...

I am sorry this post is long and wordy but I do have point at the end.

I like your solution for holding the belt in place on the crankshaft sprocket, LOL.

By advancing and retarding the cam timing (which is what you are doing) you will change the performance of the engine. You are not building a racing car here but as you have discovered you can make a small difference.

When PSA designed the engine they would have some plan in mind for the performance of the engine and the car over all I guess. Better around town or better on the high way. So the cam timing would be set for what they decided was best.

I own a 1.6i (NFU) C2 VTR with sensodrive and a 1.4i (KFV) C3 with an AL4 auto gearbox and I can tell you the performance is like chalk and cheese!!! The C2 is tight, nimble and a rocket around town but AWFUL on the high way! It over revs because there is no over drive and it shakes the fillings out of your head, its that hard! It is seriously uncomfortable at 100KPH for extended periods of time. The C3 is the complete opposite. Very boggy until you hit the power band at 2500rpm and then it just takes off to 3500 before it changes gear. Not very suited for an auto around town...but on the highway. At 100KPH the revs are right in the middle of the powerband at just under 3000RPM and it performs surprisingly nicely for a little 1.4i. Still has plenty of puff to over take. I would have expected the engine to rev a bit harder at speed but it doesn't.

Anyway...the point is by advancing or retarding one (or 1/2) a tooth I don't believe will cause any harm to the motor and if you feel it performs better for you in a certain position, more power to you. Particularly if there doesn't seem to be a "right" position.

You will find as you turn the motor over by hand, the indicator needle will move backward and forward a bit (the 5mm you mentioned). I don't know why it does that but that's why it has the spring loaded adjuster, to take up the slack and keep up the tension as the belt gets older and stretches.

Good morning/Afternoon,
thanks again for your reply, I'm just summoning up the courage to go at it again , just a clarifying point, the 5mm i mentioned was after I'd set the tension put everything back on taken it for a spin, checked it and the tensioner had moved upwards @5mm from the normal setting, this didn't seem good to me so I took it apart and reset it, but still the same result.
So I could potentially advance the cam forward or backward one to half a tooth without causing engine failure? I suppose I would be able to hear anything knocking inside.
The other thing I've just stumbled across is the frequency app which one can measure Belt tension! however I'm miffed if I can find out the conversion from SEEM to Hertz or what frequency the tu3jp sohc engines should be...
I've got a funny feeling I've done the job right but something else might be happening!
I'll report back soon
thanks again...
oh and why I keep flogging this poor donkey is before I took the belt off it was quite fun and nippy to drive, now its a slow old dog, so that's why I think/know it the belt tension/ position..

I'll just go over the way to tension the belt.

Pin the fly wheel and cam sprocket.

Loosen the old tensioner by undoing the nut and installing an allen key in the tensioner cam and turn it anti-clockwise until the old cam belt is loose, remove the old belt, remove the old tensioner.

Install new tensioner (with locking pin) and nut. Tighten nut to 10Nm. Do not remove the locking pin from the tensioner flange yet.

Install new cam belt in a counter clockwise direction ( crank sprocket, cam sprocket, tensioner, water pump).

Remove the pins in the fly wheel and cam sprocket.

Turn the engine over (clock wise) 4 times. Yes, the cam belt is loose.

Install the allen key in the tensioner cam. Holding anticlockwise pressure against the allen key, slacken the locking nut, remove the locking pin. Holding pressure on the allen key, allow it and the tensioner cam to rotate in a clock wise direction until the arrow on the indicator lines up with the notch in the base flange ( do not allow the arrow to swing up past the notch or you will have to start again!). Tighten the locking nut to 20NM ensuring the arrow remains lined up with the notch.

Remove the allen key. You are done!

Remember, as you move the adjusting cam clockwise the indicator arrow moves anti clockwise and vice versa!

Yes, after setting the tension and rotating the engine, the pointer will move (the 5mm).

You can tell how far a belt has stretched over its life by how far the pointer is from the notch. It shouldn't stretch much at all if it's good belt.

Here goes nothing
thank you
will try again by the letter...

To be honest, I don't believe moving the timing 1/2 a notch would make that much difference, at least not the amount you are talking about.

Yes the engines are "interference" engines, meaning the valves come down into the area that the pistons might occupy but again 1/2 a notch in the timing shouldn't make a difference, it's not a high performance engine.

I am not saying you should deliberately put the engine timing out by 1/2-1 tooth. What I am saying is if your best guess requires that you move the cam sprocket "out" by 1/2 a tooth you should still be OK.

allow it and the tensioner cam to rotate in a clock wise direction until the arrow on the indicator lines up with the notch in the base!!
do you mean anti clockwise as the arrow moves up towards the top of the tensioner?
and I've replaced the pin to reset the tension is this doable?

still the same , I'm going to check my idler pulley arrow again in a minute (when I've summoned up the courage) to see if its moved from the notch...
one thing my daughter said was weird when I told her was ,
there's normal power and acceleration in reverse but when I put it into first it chugged as I need to rev it abnormally on the flat...
is this a clue?