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knocking noise and misfire...


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help...went to fire the vr up this morning and something weird happened...turned it over and heard a couple of pops from the exhaust,it fired up and then made hell of a noise from the engine and sounded like it was running on five or four cylinders.it sounds like a knocking noise from right at the top of the engine,could it be a hydraulic bucket shot,as sometimes when starting it used to make a little rattle for a second or two,or could it have dropped a valve, it was fine when i came in last night with it though,no untoward noises or anything.....

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To be fair mate, I looked at the thread but unfortunately couldn't help. Therefore didn't post. I don't believe in clogging threads with rubbish and bullsh1t that won't help you. If your desperate, pick up the phone and talk to numerous specialists whos numbers are widely available on this site such as Jp automotive or the likes of stealth. Good look at getting the motor sorted.

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cheers for that guys,have done the thread search myself.gonna do a compression test tomorrow just to eliminate which cylinder its on.has anybody had any problems with hydraulic lifters sticking....as it sounds like its at cam speed....could be a valve but its really weird how its happened on startup....

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take the rocker cover off see if there is a any damage but im pretty sure your going to have to take the head off as its sounds like you have valve to head contact ie bent valves .... the chain could have jumped something like that .... jsut make sure you use someone who knows what they are doing a vr6 engine !!

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what i am gonna do is strip it at the weekend,get it to tdc on no1 and see where the cams are sitting,i cannot understand how it has possibly jumped on one cam and not the other.is it possible that the cam has snapped? have done head gaskets etc on my old gti's etc,the only concern that i have is the chain at the top..do you lock the cams and then take the gears off? and then what to do with the chain after...when i bought the car last year i was told that it had recently had a head gasket done,surely they would have at least changed the tensioner etc at that point...it had a little rattlewhen starting up,but i thought that it was the buckets filling up.but hey ho...here goes then.......

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there is guide in the premium members section about how to time the engine up mate the cam could have broken yeah but tbh just wait till you got the rocker cover off and go from there ...... they may not have changed the tensioner when they done the head gasket .... the little rattle could have been the chain guide as they are know to break up (lower one mainly) ....

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There is a how to on changing the changing the chains and one on a head gasket in the premium members section, that has helped me on several occasions!! But all you really have to do is undo the tensioner (as you would on a gti) hang the chains out of the way (or replace if you wish) then crack the head off. its quite simple but very complicated at the same time! good luck mate and I hope its nothing to bad!

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ok........ a quick update. took her apart this morning,and it looks like the cam for nos 2,4 and six has jumped a tooth,is it worth timing it back up and seeing what compressions i have before stripping it out,i figure i have nothing to lose by this.....?

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sounds like what happened to mine, blew a spark plug out, terrible noise sounded like exhaust had come off, if it's only running on 5/6 cyls, at idle there will be a noticible wobble to the engine vibration, which as you know should be smooth, if it is can be fixed with head in place, if that is the problem, can be fixed with head in place for a fraction of removing, just make sure mechanic knows what he's doing, cost me £110, running smooth again

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right....found the problem...tensioner bolt has some how lost pressure,allowing the cam for 2,4,and six to jump back a tooth.....re timed it back up,filled the tensioner with oil,re fitted it and it is now as tight as....turned the engine over to check compressions,1,3,5,and 6 have now 12 bar plus.....2 and four have 0...suspect bent valves...have started stripping out...have also noticed upper chain runner has cracked in two places,and the upper tensioner has also worn pretty badly....any ideas on cost to replace tensioners? can do the head myself...

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