if the timing belt did jump a tooth what would the symptoms be,the reason i ask is my tensioner for the injector pump went a few days ago, we put in a new tensioner and all was good for 2 days.then today started the car and heard a clonk bang sound so turned it off straight away turns out there was a piece of the old tensioner stuck behind the cam pulley so the bang was that shooting through the plastic housing and breaking the cam seal housing,so changed that aswell.car is running again but it sounds louder than before and there seems to be a knocking sound so ime wondering if it could have jumped a tooth.we did try adjusting the timing on the pump and it quietened it a bit but not enough.
cam belt skipping a tooth
- Thread starter brownie 25
- Start date
2.5 TDI Engine AKE same as your self.i adjusted the timing on the pump in either direction with no joy.car is driving fine, power is still there but it is like a tractor.it was noisy previously to this happening but now there is a knocking as well ,is yours much louder than a 1.9 when its ticking over
The noise is quite subjective, I've never run mine alongside a 1.9 to compare, the 2.5's aren't quite though are they. More telling is if the noise is different to how it was before.
Does the knocking occur all the time, cold or warm, and increase with the revs? Could it be EGR valve, an injector or a hydraulic tappet or something?
Does the knocking occur all the time, cold or warm, and increase with the revs? Could it be EGR valve, an injector or a hydraulic tappet or something?
yes it increases with the revs, next on my list is off with rocker cover to check tappets,i dont think its an injector but who knows.where is the egr valve located i didnt think this could cause knocking.
It can jump a tooth and you will need VAG special tools(camshafts locking plates a\nd krankshaft pin) to time the engine properly. Do not even try to adjust without the tools as you will have shattered rocker arms and the pistons will hit the valves ! Trust me, i have rebuilt dozens of them engines and while i am able to build the engine with eyes shut and without locking tools, i allways find it very fiddly and imprecise as the cams keep moving about. If there is metallic noise then one of the cams is out of sync and the timing will need re-setting. "Mark-and-pray" cambelt jobs on them engines isnt reccomended as the clearances are verry small and you will have piston and valve dammage if you do it wrong wich will lead to dropped valves sooner or later wich will mash the pistons. Where abouts in the country are you based ? I could lend you a hand if within reasonable driving distance from North london...
@adamss.
thanks for the offer to help out but i live in Ireland is that to fare for you to travel lol.
i am going to take off rocker covers today to see what its like in there.if i was to put new cams into the engine how do i time them,i have the crank locking pin.is there marks on the cam shafts or how do i time them, ive all ready done the timing belt and had 4 months of trouble free driving so i kinda have an idea of what ime doing just not sure about fitting new cams and timing them.
thanks for the offer to help out but i live in Ireland is that to fare for you to travel lol.
i am going to take off rocker covers today to see what its like in there.if i was to put new cams into the engine how do i time them,i have the crank locking pin.is there marks on the cam shafts or how do i time them, ive all ready done the timing belt and had 4 months of trouble free driving so i kinda have an idea of what ime doing just not sure about fitting new cams and timing them.
there is a cut-out on the back of the cams where the sprockets are, make shure they are perfectly lining up with the edge of the head when you look trough the camshaft bearing. There is a plastic cover on the driver side and on the passenger, the vacuum pump needs removing in order to see the slit. The locking tools fit there. You can easily make 2 plates that will fit the slot if you have some metal plate and a grinder. Trouble is that the cams are much easier to set up on the bench than in situ a you can see what you're doing. both cams slots need to be on line with the edge of the head. Beware that its easy to set up the long cams upside down (180 degrees out of phase and the engine wont start or will be very noisy due to piston and valve kissing ! Also make shure the crank is locked at TDC and use some petroleum jelly to keep the rocker arms and trust pads seated on the tappets and valves. A good magnetised screwdriver will be a god send as you most likely will drop a few rockers while setting up the 2nd cams. If you done the job properly (all cams cuttouts for the head bolts will be on the outside and perfectly perpendicular with the head then fit the sprockets loose (make shure they turn on the cams) then feed the cambelt in the ussual way. Make shure you turn the engine by hand a few good turns and ckeck if the lifters/rockers are seated properly (lightly oil the contact faces with clean oil). Get the engine again at TDC then fit the looking tools again and make shure they fit well. Refit the rocker covers, fuel hard lines and return lines then check the pump timing and if you're happy then crank the engine. Be carefull so you dont leave any tools in there while cranking the engine ! Crank the engine for 10-15 sec. so you build-up oil pressure (it wont start right away due to air in the system!) then crack the unions open while cranking to expell air. If the engine starts and runs well then its job done, if not back to square one- check the cams again ! Be carrefull and make shure you tighthen every nut and bolt so you dont have any surprises... Hope this helps !
yes very helpful thanks,good point about the petroleum jelly i dont know how many times i dropped the rockers last time.please keep an eye on this thread because most likely ill be back.
ok ime back,timing was out by about 2/3 degrees so thats sorted now.running fine BUT still have the `raspy tappet sound i know camshafts and rockers are slightly worn so do i just drive away or consider new cam shafts rockers and tappets.
Timing is still out unless the cams are realy badly worn... I suggest you take a good picture of the lobes and post-it here...
^^ ime nearly possitave timing is ok now.the noise is hard to explain but ime nearly sure its cams there is at least half a mm on cams and same on rockers.the noise is really only there when ticking over,it drives 100%, now saying that i suppose the actual engine noise is blanking out the other noise
Half a mill isnt that much, can you feel it with your finger nail ? How are the lifters and rocker arms ? the lifters/rockers are wearing sometimes in a weird way and they wont allow the valves open properly wich will manifest in poor engine operation overall. Rattling noise is still the cam advanced, i had fitted a set of aftermarket cams to a mate's a4 a few years ago and they were rubbish, no timing marks on them and they had the same ratling noise. Had to play adjusting the cams for a few days and i took the cams off a dozen times and the heads off twice ! I ended getting a set of 2nd hand genuine cams and fitted them instead and told him to bin the new replacements... you really get what you paid for with these !
ya you can feel it with your nail,as for lifters and arms i bought the car with engine trouble and then got a second hand engine, when i fitted the new engine it was running rough aswell so when i took off the rocker covers a good few of the tappets were seized and some of the rocker arms had fallen off so basically i made the best set of arms and tappets from the 2 engines.so do you think tweaking the timing could help.any tips for best results.
You should not mix and match tappets and rockers as they wear in a accelerate way ! I would throw a full set of lifters, trust pads and rocker arms and make shure the timing isnt off by much. Timing the pump will also help big time as the engine will run smoother and be more ecconomical as well.
May not be relevent mate, but the N108 commencement of injection valve, is a preinjection unit that seriously quells combustion clatter, you may have knocked the plug off or have a wrong plug on it as several are 2 pin jobs that fit each other like the EGR solenoid and the IMTS sensor, have you scanned it for missing sensors....mine had a replacement engine fitted and the egr plug was on the imts, the imts plug was just dangling and they fitted an unused harness plug to the egr, then blew the fuse to the engine sensors so the N108 no longer worked, sounded like a van engine.
Now smooth and sweet with the fuse fixed, and the plugs on the correct sensors.
May be no use to you but you never know.
Now smooth and sweet with the fuse fixed, and the plugs on the correct sensors.
May be no use to you but you never know.
adamss24, thank you very much, after almost a full day of searching for information i cannot thank you enough for the statement "(all cams cuttouts for the head bolts will be on the outside and perfectly perpendicular with the head). i was sure that is how i took them out but somehow untill i read that i didnt believe myself and thought i only checked the right bank but not the left. i hope i can finish my job off now...very many thanks....
oh by the way, i bought all my parts from TPS but somehow the cams have no audi markings on them, does that not seem odd as the worn out cams i have taken out all had original audi logo stamped on them, only reason i am a bit dubious is that ebay sells a set of cams, rockers, spacers all in for about £600.00. i have paid more than double for bits from the dealers and yet a nobody would look at them and maybe say customer has been conned....not important as i know the truth but dubious anyway.....thanks again........
oh by the way, i bought all my parts from TPS but somehow the cams have no audi markings on them, does that not seem odd as the worn out cams i have taken out all had original audi logo stamped on them, only reason i am a bit dubious is that ebay sells a set of cams, rockers, spacers all in for about £600.00. i have paid more than double for bits from the dealers and yet a nobody would look at them and maybe say customer has been conned....not important as i know the truth but dubious anyway.....thanks again........
