cambelt jumped a tooth.
 

hi all, think me cambelt has jumped a tooth, have now checked it 3 times and it still comes back to the same postion, your thoughts please.
http://i189.photobucket.com/albums/z...arbits3014.jpg
and im 100% the crank is lined up. is in the same postion as this one.
http://i189.photobucket.com/albums/z...ingMark850.jpg

cam belt
 

I would check to see if the tensioner is operating correctly and or is the belt stretched oh did you use a new belt? Hopefully you haven't bent any valves as it's half a tooth out and depending on how many times you've tried to start the car you may or may not have done damage to the valves.

Replace the belt and see if that resolves any issues with the car

make sure the engine rotates without resistance if there is a lot then the head will have to be removed to check the valves for bending otherwise try replacing the belt

jumped tooth
 

my timing jumped on my s70 t5 it cut out and wouldn't restart then when i dismantled it 13 valves were bent . i cant remember the exact details of timing marks as it was over a year ago but i fitted a new tensioner when i put car back together and it hasn't happened since it was about 70 quid for part . strange thing was old tensioner was still working but must have lost its strength for a sec to let belt slip . hope this helps .

not yet changed the belt, and it starts first time etc, just it runs on when you turn it off, has been doing it for a few wks etc. gunna try and up load the short vid of it .

how do you put the link on for a vid from youtube, and do you have to be signed into youtube for others to view.

ooooppppps

what makes you think its out? and why would it have changed if youve not had the belt off? looking at the picture you seem to have marked the tooth gap and on the other sprocket the tooth itself! that will make it difficult to line up properly even if its not jumped out!.
every car ive ever known that the belt has jumped has usually been more than 1 tooth and engine damage has resulted the only times ive known the belt to be/ or appear to be 1 or 1/2 a tooth out has been when the belt has been changed and mis-timed.
check the belt is under proper tension as if its not it will effect the position of the cam wheels in relation to each other and the crank.

I have just done the timing belt on my 960 and it was a bit further out than yours is showing,dont worey it wont be damaged but you must check out why its happenend in the first place.
I have to say lining up the cam timing via a plastic cover is awfull and bad design imho,mine was warped.

looking at the photos the marks are about right,when changing cambelts they hardly ever lined up perfect.

if I remember there is an air solenoid somewhere that shuts off to stop running on,this could be faulty (if fitted on your engine)

mines gone right down hill, runs like a bag of sh.t- popping through the exhaust and when you put your foot down there just isnt the same amount of power there anymore. looking at the other posts re timing marks, they all say the top 2 should line up spot on in the v,s mine has always felt lumpy on idel, and when you rev it , it feels like its missing , and on tick over you can feel it missing if you just hold the sterring wheel, all has been changed ie leads-cap-arm-plugs. you can also here the pitch of the engine running change through the exhaust.

as it is still in running order i am assuming there is no mechanical noise can you not take plugs out and test compressions on each cylinder if you haven't got a compression tester you could get a rough idea by covering each plug hole in turn if you know what i mean

hi there, comp test done with good readings across all 5. 235-234-235-234-235. summit like that, ive posted the readings in another thread.also car has had a head test using a coloured dye in a tube put ontop of the water expantion tank etc, dye stayed the same colour, so there was no problems.
the dam thing sounds like its only running on 4 at the mo. getting sick of the dam thing now lol.

Don't know what (com) should be But they seem ok pretty near each other So i would i think look somewhere else Plugs leads not familiar with setup i mean coil or coil packs I'm not saying it hasn't jumped a tooth but with (com) pressures that you have i would not think it has. Fuel side or electrics my moneys on let us know how you get on hope you get it sorted

hi all, so if i am one tooth out is it poss just to take the tention off the belt etc and turn it back into place and re tention?????

it is possible to take of the belt and reposition if it has jumped a tooth,but if it hasn't had a recent belt that's been fitted incorrectly you should be looking into why its jumped ? if the belt was tight when removed it wont have jumped.

might be worth getting the codes read,might give an indication if its a faulty sensor ie air flow sensor/coolant sensor etc.

since ive had the car its always felt like its missing abit, the belt might have jumped when it was fitted, im told its easy to make this mistake and the car will still run on a tooth out, do i need any special tools to re loosen belt etc and how do you remove the serpentine belt or does it not need removing.

you cant line up the timing belt on the outer pulley marks this is for static timing with a timing gun you must remove the crank pulley that the fan belt goes on to and the marks are on the timing belt pulley under that its the only way to check if its lined up
Also a timing belt rarely ever jumps and if it does it will remove other teeth off the belt in the process and 99 times out of 100 it will cause valve to piston contact
hope this helps

laurence

Caution here mate, just because the cam pulley marks are out dose not mean the timing is incorrect. When we replace timing belts we use the rear cam locking tool to time the cams correctly and lock the crank with a dedicated pin.

The cam pully is attached to the cams by 3 bolts, the puley holes are elongated which alows the cam puleys to move. This is so during setting the tensioner the load is distributed on the full run of the belt.

To confirm cam and crank correct sequensing an oscilloscope is used to vew cam and crank corilation. Also your compressions do not indicate incorrect valve timing. A vaccume guage should show around 22 hg at idle confirming correct valve timing.

ok thanks very much for your info.

thanks very much, was just reading the haynes man, and it states that them to marks should be bang on in the middle of the v-marks on the case, so if the bottom crank was in line and no 1 piston is at the top of the stroke, and the rotor arm points to no1 on the cap then why would it be just over a tooth, so are we saying then that as above ie crank- piston no1 -arm at no1 are we saying the timing isnt out. just trying to find out why the car trys to restart sometimes when you turn it off, its done it b4 and smoke came from under bonnet, when i unclipped the air filter lid and lifted the filter the white smoke came out of there and it smelt off fuel.

the volvo standard time is 1 hour to replace the cambelt as per manual, the 3 bolts on the cam pulleys are not loosened on belt replacement so the cam locking tools are not required,they are only required if the head/cams have been removed.

So why the elongated bolt holes on cam pulleys?

If you feel confident enough, I would remove the belt (lock it up first) and see if you can get them marks spot on ie turn it back a tooth, once you have done this and retensioned belt, turn over by hand twice and see if all lines up again, sometimes an engine can look a tooth out but when you go to put it back a tooth its miles out meaning it was right in the first place, have you checked the tensioner for play or and idler pulleys if there is any?

As I say if after you have moved it back a tooth and it all lines up better than before after turning it over by hand cranking twice, then i think you would have solved it!

what do you need to lock it off???

to allow the cams to move on the pulleys slightly if the belt is installed while installing the locking tool.

the locking tools at the crank and cams are required when reinstalling a head or if a front cam seal has been replaced,the cam pulleys are fitted finger tight so they can spin freely on the cams then the belt is tensioned then the 3 bolts are tightened,this only needs carrying out as mentioned or if the front pulley bolts have been loosened and you suspect a cam has moved.

changed about 100 cam-belts over the years on Volvo's and so long as you align the marks (that can be half a tooth out as per photo) and make your own tipex marks then you cant go wrong,the tools aren't required as its been set (valve timing) at the factory.

so are we saying i can just take the tention off etc and turn it back a notch, that picture ive posted is the crank spot on, the top two are as they are in the picture, rotor arm points to no1 as set in pic, and piston number 1 is at the tdc. anyadvice on best way to do would be great.

Right there is absolutely no need to slacken the cam bolts to tension the belt I have dont alot of these timing belts in my time,there are also no specialised tools required.
As for the elongated holes I have seen none on this engine,and when checking the bottom timing mark the crank shaft pulley has to be removed to see the mark behind it.
this information comes from the new autodata cd I have recently recieved so if its wrong then so is every other garage lol

laurence

im hoping ive done the crank postion right, in that picture that was posted with the pulley near off you can see the mark if you shine a tourch down from the top of the engine you can see the mark with the pulley still in place if you look at the pulley thing the belt goes round there is a odd one out well thats what it looks like to me im sure it has a small pin like hole on the spline, quote me if im wrong but im new to all of this, and would love the input info etc.(please note i have not touched anything just alined it all up as im trying to find out the cause of the engine what i call running on-and shutting of dead sometimes.) and looking at the top to pulleys the right hand side one inlet i think is out dosnt sit in alinement, (ps volvo mec has told me they should both sit spot on in the middle of the marks on the back case cover.)

You dont need to literally lock this engine, just make some nice clear marks I use tippex it doesnt have to be on the timing marks themselves just mark your own points, as long as they are easy to see, just get your crankshaft at TDC as in your pics, then make the marks onto the pulleys and onto the cover, its just so basically if it moves when removing the belt you can at least put it back where it was, but try and get those original marks to line up better, it may be a long way out after you move it one tooth, that way you will know it was right at first, when I first started doing timing belts, sometimes after I fitted the new belt I would spend ages trying to get the marks spot on but a lot of times it would never be dead on the mark but if i tried a tooth either way it would be obviously out, so i would set it on the tooth i could get the closest to it, dont forget to rotate the crank twice to bring it back to TDC by hand and re-check all the marks, This is very important!

thankyou very much for your time, can you tell me does the (serpintine belt) need to be removed, b4 i do the other, or do you leave it in place???, if remove how do you do it, or is there a link on that topic.

http://www.volvoforums.org.uk/showthread.php?t=46959 there you go mate

http://www.volvoforums.org.uk/showthread.php?t=46957 and the timing belt

Hi, It sounds to me like your ignition timing is out, from what I've read from your description you seem to be getting pre-ignition. I don't know how your car is timed, has it got a distributor cap. Also I can't imagine the timing belt jumping a tooth without stripping teeth off the belt. Have you tried timing it. Hope this helps. Ian

hi ian, im told i carnt do the timing re gun, as the dizzy side of things dont move etc, as it all done by ecu?? and yes it does sound like pre ignition, what can i check re this.

I personally would get an emissions test done by some garage because you may have an over fuelling problem ,this could be down to various components within the engine management system but the co figure should tell if its running too rich causing pre ignition and might help diagnose the problem


laurence

thats another good peice of info.thanks.

Bring it round if your not too far away and il move that belt for you if you want, just to eliminate mate, sounds like its driving you mad

cam belt jumped a tooth
 

did you replug the knock sensors in or has a plug fallen off ? The knock sensors will adjust the timing till the pinking stops maybe one has failed. The problem is they're bolted to the side of the block up by the PCV system so the manifold needs to come off.

BTW is the car throwing any codes off ?

hi char, no dont think its been knocked etc, would that be the one near to where the oil trap thing was fitted???

hi m8, driving me mad, its never ending, me thinking of just cutting my losses on it and getting shot of it, where abouts are you m8, anywhere near junction 16 m6???