Cambelt Tensioner

[simonplatt]

i have recently fitted new cambelt and water pump, on completion all was fine for 50 miles or so, then it lost compression.

the belt has jumped and the timing is out, and there is less tension on the belt although the tensioner has not slipped.

i have not got to the valves yet and fear the worst.

 

i was a little confused (and still am) about the tensioner proceedure, but was convinced i had it right when i did it.

 

my take on it was (is) to turn tensioner clockwise To first position, tight, then rotate crankshaft twice, then go back clockwise, (loosen) to second position, and job done.

 

advice appreciated.

[coastline taxis]

cant really answer this for you as we havnt a clue what car year or engine it is

[simonplatt]

hi. sorry for delay. car is 2004 c3 desire 1.4  8v petrol.

 

i now have the head off, and 3 inlet valves are bent. the apparent cause of this was a small piece of casting (broken off from mount) which had dropped onto the crankshaft sprocket and got between that and the belt.

 

there appeared now to be less tension on the belt, although the tensioner hadn't moved, and when i slacked it off to go through the tensioning procedure (as a test) it would not get to the number 1 postion, so i figure that the belt may have stretched. but in any event i could, even when fitting it new continue to go in an anti clockwise direction after passing the point of maximum resistance.

 

so i think maybe to renew the belt again. but should belt stop. at position 1 ie. being unable to go farther, or just stop at the mark?

[simonplatt]

still not sorted. i have been down with flu, and just starting to feel better.

 

i have replaced the inlet valves and ground in the exhausts as well. and now back to the cam belt.

 

i note that the new tensioner has a much stronger spring than the old. but i cannot get the pointer to the max tension position. it goes about half way then slacks off again, however at this all the slack appears to be taken out of the belt.

 

i can't understand why there is a need for the pin to hold the tension, i have not seen this used in any vids, and tightening the nut holds it anyway.

 

going from the haynes manual, i can get a 90* twist and approx 6mm on the long run (although this is a guess, using a ruler as a straight edge, as it seems impossible for me to measure.)

 

any advice appreciated.

[paul.h]

This topic is worth a read http://www.citroen-owners-club.co.uk/citroen/topic/23157-timing-marks/

 

I have attached a photo of the tensioner on our C3 (2003 1.4i 75 hp petrol) before I removed the old timing belt.

[simonplatt]

thanks for that, did you use the tensioner locking pin in the process? i didn't and am wondering if that is the problem. i couldn't see the need for it first time around as rotating with the hex wrench brought the pointer to the required positions, but this time it doesn't.

 

going to have another go tommorrow (hopefully)

 

i am now questioning my previous diagnosis .

 

QUOTE//. the apparent cause of this was a small piece of casting (broken off from mount) which had dropped onto the crankshaft sprocket and got between that and the belt.UNQUOTE//.

 

and fear that if it was just incorrect tension, then it could happen again.

[paul.h]

It is 6 years since I did the job so can not remember much. The tensioner pin from memory was part of it to stop it unwinding, but I am not sure. The Citroen service box procedures have the following:

 

Refit the timing belt .

Position the timing belt, long span correctly tightened, in the following order :

• Crankshaft gear Retain the belt with the tool 5 (a clip to use on the crank pulley but a piece of card will do to push it against the pulley)
• Camshaft pulley
• Water pump pulley
• Roller tensioner
• Remove cam shaft and flywheel setting tools

Setting belt tension

Rotate the roller tensioner ( 7) using an Allen key (at "a").

Position the index " c" in position "f- Haynes position 3 max tension position" Tension the belt to the maximum of the space indicated.

Hold the roller tensioner ( 7) Using tool [4 - the pin that goes in the tensioner base].

Tighten the roller tensioner fixing nut to 10 Nm.

Turn the crankshaft 4 turns in the normal direction of rotation.

ESSENTIAL : Never turn the crankshaft backwards.

Reinsert camshaft and flywheel setting rods [1], [2] to make sure that the timing setting is correct.

Remove setting rods [ 1], [2].

 

Adjusting the tension

Loosen the tensioner nut while maintaining the position of the roller tensioner Using an Allen key at "a".

Then bring the index " c" to its adjustment position "g - Haynes position 2 normal tensioner position".

CAUTION : The index " c" must not go past the slot "g". If it does, repeat the timing belt tensioning operation.

Hold the roller tensioner ( 7) in this position, using an Allen key.

Tighten the roller tensioner fixing nut to 20 Nm

ESSENTIAL : The tensioning roller must not turn while its mounting is tightened . If it does, repeat the timing belt tensioning operation.

[simonplatt]

well its been a while now and its still going. so time to report in case anyone else has the same probs, and questions. and it may be of help.

fitting of the belt was straight forward by following the instructions, but when it came to setting the tensioner it just wouldn't go to the max tension reference mark.
i could push it there with my fingers but that made the belt slack.
there were several reasons i could think of why this was so, but i ruled out them all.
i tried the old belt (done 99000) the last new one, and the present new one, all were the same.
i tried the old tensioner, with no difference. and i note here that the new tensioner spring was/is significally stronger.
so i read and re read the instructions for all models, with and without auto tensioner, then did this...,

turn the tensioner anti clockwise until max tension is achieved, ignoring the pointer which was half way between the 2 settings. locked this down and went through 10 revolutions, (dont know why as the only reason that i can see for this is to settle the belt, and so seems excessive, but whatever, followed the advice) checked as instructed and all was well.
backed off (clockwise) to 'normal' setting. did some more revolutions.

then to check i put a steel rule along the belt from the crankshaft pulley to the camshaft pulley, and checked the amount that the belt could be deflected which was approx 6mm.

looked looked and looked again, couple of cups of cofee later i decided that i could do no more, so built it up, crossed my fingers and turned the key.

started straight away, sounds as sweet as a nut and is running fine. hopefully it will carry on doing so.

[paul.h]

Good to see your car is now ok.

 

When I replaced the belt on our 2003 C3 I was not sure if I had got the tensioner right. After several attempts at setting it I gave up trying to get it exactly right and put it back together and luckily it was ok for many miles and years. The tensioner on our C5 is the same as the C3 and when its belt needed replacing this year I paid the dealer to do it - the labour cost was not too great compared to possibly damaging the engine plus I want to keep the car for a few more years. Probably once you have done a few of these tensioners you get used to them but as DIYers, we only see them every few years, if that.

[simonplatt]

got to agree with you, don't anyone attempt this unless your confident that you can do it, unless of course you have no other choice. as once you have it stripped down in your back yard you're pretty much on your own, except for the advice of the forum of course. but always way up the situation first.

 

even if you did it right, you tend to spend a while wondering whether you did or not.