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[chrisdb]

My engine sounds like a London taxi - long story! I made a recording of it. It's quite loud because the engine is cold but the knocking sound coming from the top of the engine is just as loud when the engine warms up.

http://sp.sintinol.co.uk/Bad%20engine.avi

Grateful for any ideas.

[Pitchfork]

Is is a Traktor (TD)?

[chrisdb]

Is is a Traktor (TD)?

No, but sounds like one It's a 3.0 v6 petrol.

[jonathanh]

difficult to tell really (crap speakers on my lappy).  Are you down on power?  Cam timing?, any word done recently?

[chrisdb]

I have not driven it since the noise started. Here's the history:-

Left hand side exhaust manifold gasket needed doing as well as timing belt. Stipped down, removed head, replaced gasket, put back did timing.

all seemed OK but slight knocking noise seemed to be coming from right hand side camshafts. Stripped down to re-check the timing and all was OK except that the right lower tensioner was leaking grease - it was a complete new set I had fitted. Replaced all the tensioners with another new set. Timed up, all OK except still had knocking sound from right hand side, as well as tappety sound from left.

Removed plenum and inlet manifold - upper and lower to check but all was OK. Put back manifold and plenum and now have this noise. I did have problems with the exhaust too - the gasket was leaking between the manifold and cat - lots of problems - had to drill out old stauds which were a different type - replaced with genuine studs. Exhaust is OK now I think.

Could the manifold nust have worked loose fron 20nm? The cat - manifold bolts had worked loose a couple of times which is why I replaced the nuts and studs...

Out of ideas now but too scared to drive it.

[RobG]

Have you removed aux belt and ran the engine to discount ancillary problems :question

[jonathanh]

hmm - did you have a problem with the belt slipping when you did the timing.  If so are you sure that you've got the cams on the right timing marks?  you need 1,2,3,4 from L to R

apologies if I'm barking up the wrong tree - just remember someone on here had a slipping belt

[chrisdb]

hmm - did you have a problem with the belt slipping when you did the timing.  If so are you sure that you've got the cams on the right timing marks?  you need 1,2,3,4 from L to R

apologies if I'm barking up the wrong tree - just remember someone on here had a slipping belt

Yes, I had a lot of problems with the belt slipping. It was caused because I had too much slack in the belt, after after lots of advice I managed to tension the belt properly and the timing stayed spot on after I hand cranked several times. A couple of times when I was having trouble the cams got badly out and I had to rotate back to 60btdc but I was very careful to not force the crank when it hit a valve. I suppose I should check the timing again now, but if it has moved them I'm really stuck as I don;t know what would cause this after everything is set and tensioned properly...

[chrisdb]

Have you removed aux belt and ran the engine to discount ancillary problems :question

I did this when I had the very light faint knocking noise the first time - it was more of a grinding than knocking noise. The noise was still there with the belt removed.

[Elite Pete]

hmm - did you have a problem with the belt slipping when you did the timing.  If so are you sure that you've got the cams on the right timing marks?  you need 1,2,3,4 from L to R

apologies if I'm barking up the wrong tree - just remember someone on here had a slipping belt

Yes, I had a lot of problems with the belt slipping. It was caused because I had too much slack in the belt, after after lots of advice I managed to tension the belt properly and the timing stayed spot on after I hand cranked several times. A couple of times when I was having trouble the cams got badly out and I had to rotate back to 60btdc but I was very careful to not force the crank when it hit a valve. I suppose I should check the timing again now, but if it has moved them I'm really stuck as I don;t know what would cause this after everything is set and tensioned properly...

That doesn't sound good Chris, the valves don't take much to bend. I would check the timing again and if its OK do a compression test.

[chrisdb]

Thanks Pete. It sounds like maybe I have done damage in that case. A couple of times while cranking back round to tdc the crank wouldn't budge and I guessed that this was an indication the valve was hitting, but maybe that gave me a false sense of security and I've actually bent some valves without realising.

I've been having to use a hire car for the last couple of weeks andit's getting really expensive now so I think I'll buy a couple of heads and just replace them. Not loking forward to that job

[jonathanh]

do not rush into buying new heads just yet.  I would be surprised if you have managed to bend a valve IF you never forced anything.   Anyway, my first suggestion is to strip the cambelt cover off and double check the cam timing.  remember the crank pullies have two timing marks; you need to align the right one of the pair for each cam.  it may be possible that you have got the wrong alignment mark.  If not, well the work you've done to stip the cover off is not wasted if you are fitting new heads.

I may be able to help out on sunday if you want

[chrisdb]

do not rush into buying new heads just yet.  I would be surprised if you have managed to bend a valve IF you never forced anything.   Anyway, my first suggestion is to strip the cambelt cover off and double check the cam timing.  remember the crank pullies have two timing marks; you need to align the right one of the pair for each cam.  it may be possible that you have got the wrong alignment mark.  If not, well the work you've done to stip the cover off is not wasted if you are fitting new heads.

I may be able to help out on sunday if you want

Thanks Jonathan, I'll take your advice. The locking kit I bought was quite cheap and the timing gauge does not fit between the cams very easily. I grounded it down slightly in my sander but it was still very stiff. Maybe the gauge is faulty? I'll certainly strip it all down though and check again. If the fault is not obvious then I will take you up on your offer of help

Cheers, chris

[chrisdb]

Just remembered something else... When I stripped down the timing belt I found that the knock sensor wire had been trapped and crushed by the aux belt tensioner. I cut out the damaged part of the wire and did a solder repair, and the used heat shrink wrap to cover it all.

When I first started the car after this I had the EML list and a number of codes, one of which was the knock sensor. After I drove for about 10 minutes the eml went out and stayed off. If there is a problem with the knock sensor what symptoms would I get?

[Marks DTM Calib]

I assume athat all the cam bearing cap are ok and torqued down?

No T vents missing in the heads?

All followers are ok?