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[TheBoy]

We left it running long enough yesterday to go closed loop, and from Tech2 side, no sign of overfuelling, trims looked about right, lamdas going rich/lean/rich/lean as expected.

All 3 of us agree the noise is from 1/3/5 bank, but can't agree which pot - my own feeling being 3 or 5, but so hard to pinpoint. Listening stick didn't really help either.


I think the 3 of us have now ruled out:

Foreign objects in cylinder (unless embedded in piston, and clouting head) - good compression on all 6, absolutely no sign of any damage to any plug.

Ignition - changed leads and plugs.

Overfuelling - Kevin Wood in the week has checked injectors, and changed injectors, and FPR. Tech2 data seemed normal when it went closed loop.

Lifters on the side we think the noise is (inlet and exhaust, and inlet only on 2/4/6 bank) - visually checked.



I think the 3 of us are 100% completely out of ideas as to what to try next.


 :-/

[cem_devecioglu]

today I compared the noise from youtube against
piston slap, lifter noise etc..

the most similiar one was #1, #2 I'm afraid..

#1 http://www.youtube.com/watch?v=HeHxuYi-138&feature=related

#2 http://www.youtube.com/watch?v=RuiJffXOJTY

#3 http://www.youtube.com/watch?v=-_bOFOy-3Ic

#4 http://www.youtube.com/watch?v=SAq9vAjHHEk&feature=related

http://www.youtube.com/watch?v=aps-SbcPEEk

http://www.youtube.com/watch?v=tjGdBmgVDuE&feature=related benziyo

http://www.youtube.com/watch?v=FzLXA4sBAKQ&feature=related

http://www.youtube.com/watch?v=UmZ1F8V8pc8

http://www.youtube.com/watch?v=F-AKcs0q6II&feature=related valve noise

http://www.youtube.com/watch?v=UmZ1F8V8pc8

[Omegatoy]

this may be of absolutely no use at all, but
when i bought the courtenay turbo omega, it had a strange engine noise which is why i got it cheap, anyway the noise was very hard to pinpoint as it appeared to be coming from the cam area, and apparently the previous owner had had 2 or 3 mechanics look and listen to the engine and 2 of them were sure the noise was top end. anyway when i had it home (it drove perfectly from essex to oxford apart from the noise) and had a good look and listen and a few exploratory pokes inside, i discovered that the big end had wornbadly and the noise was the pistons just catching the valve but not actually damaging it!! so the compresssions were good and the engine ran fine would tick over all day and drive although i didnt rev it high!! have heard it on  couple of other v6 engines as well, so i think yoiu could do worse than look for the same thing?
jm2pw
G 

[TheBoy]

this may be of absolutely no use at all, but
when i bought the courtenay turbo omega, it had a strange engine noise which is why i got it cheap, anyway the noise was very hard to pinpoint as it appeared to be coming from the cam area, and apparently the previous owner had had 2 or 3 mechanics look and listen to the engine and 2 of them were sure the noise was top end. anyway when i had it home (it drove perfectly from essex to oxford apart from the noise) and had a good look and listen and a few exploratory pokes inside, i discovered that the big end had wornbadly and the noise was the pistons just catching the valve but not actually damaging it!! so the compresssions were good and the engine ran fine would tick over all day and drive although i didnt rev it high!! have heard it on  couple of other v6 engines as well, so i think yoiu could do worse than look for the same thing?
jm2pw
G 

always appreciated, but if its bottom end damage, then its off to be made into baked bean cans 

I heard your turbo (black one?) the noise sounds different to me, but that was a long time ago  :-/


But then I think we've explored all possibilities near the top  :-/

[guncharmer]

Now i am no expert but will throw in a theory.
Valve seating,top end crud possibly disturbed when fitting injectors etc and then a particle preventing a less than perfect seal or a piece of crud departed from what was a perfect seal,this then perhaps overcome by adding oil to the cylinder.So head off and overhauled or just drive it potentially allowing it to improve.Worst case scenario (as i am having a wild guess) is the engine destroys itself but in the absence of any other cures  and head renovation not being cost effective then there doesn`t seem a lot to lose.

[Bent valve]

Have you tried running it with each plug lead disconnected in turn to ascertain which cylinder it is?

[TheBoy]

Have you tried running it with each plug lead disconnected in turn to ascertain which cylinder it is?

There is no misfire.

[Bent valve]

Have you tried running it with each plug lead disconnected in turn to ascertain which cylinder it is?

There is no misfire.

There might not be a misfire, but removing the spark from the offending cylinder will give you an indication of whether the noise is occuring under load or not

[feeutfo]

this may be of absolutely no use at all, but
when i bought the courtenay turbo omega, it had a strange engine noise which is why i got it cheap, anyway the noise was very hard to pinpoint as it appeared to be coming from the cam area, and apparently the previous owner had had 2 or 3 mechanics look and listen to the engine and 2 of them were sure the noise was top end. anyway when i had it home (it drove perfectly from essex to oxford apart from the noise) and had a good look and listen and a few exploratory pokes inside, i discovered that the big end had wornbadly and the noise was the pistons just catching the valve but not actually damaging it!! so the compresssions were good and the engine ran fine would tick over all day and drive although i didnt rev it high!! have heard it on  couple of other v6 engines as well, so i think yoiu could do worse than look for the same thing?
jm2pw
G 

always appreciated, but if its bottom end damage, then its off to be made into baked bean cans 

I heard your turbo (black one?) the noise sounds different to me, but that was a long time ago  :-/


But then I think we've explored all possibilities near the top  :-/

we placed an extension bar down the plug hole with all plugs removed and turned the engine over by hand via the crank pully bolt, feeling for loss of motion at top and bottom dead centre via the extension bar, and wrocking back and forth on the crank pulley bolt, all nice and tight no loss of motion on any cylinder.
 
Expecting bottom end crank bearing noise to be deader deeper noise than what we have, if that makes sense.

There are no visible marks on the piston crowns wnen looking line of sight through the plug hole.

However not sure if this engine has half moon valve shape cut outs in the piston crowns, we could not see any, so not sure if the a valve mark collision in the piston crown would be visible via the plug hole. Its not possible to see the piston full area via the plug hole via line of site. The piston crown is curently wet with oil so any marks would be shown if in line of site.

[feeutfo]

Now i am no expert but will throw in a theory.
Valve seating,top end crud possibly disturbed when fitting injectors etc and then a particle preventing a less than perfect seal or a piece of crud departed from what was a perfect seal,this then perhaps overcome by adding oil to the cylinder.So head off and overhauled or just drive it potentially allowing it to improve.Worst case scenario (as i am having a wild guess) is the engine destroys itself but in the absence of any other cures  and head renovation not being cost effective then there doesn`t seem a lot to lose.

Just driving it was the original plan, with brake down cover. But we had time and opertunity to investigate further. Seemed a bit of a waste if it did explode. Personally i want to know whats up with it. But there comes a point when its not worth preceeding. If we remove the head and find or repair nothing, put it back together and its the same, whats the point?
If we remove the head and find damage, is it worth repairing....?

Car isnt worth a great deal and needs rear donut bushes.
But it was only another couple of hours work to get the lpg up and running.

[Lazydocker]

Certainly doesn't sound deep enough for bottom end damage and, TBH, I'm not convinced it's damage at all :-/ :-/

Had you not tried different injectors I would have said that there was a bad injector... I've encountered it on a Transit in the past and it sounded just like it.

I'm lost

[TheBoy]

Certainly doesn't sound deep enough for bottom end damage and, TBH, I'm not convinced it's damage at all :-/ :-/

Had you not tried different injectors I would have said that there was a bad injector... I've encountered it on a Transit in the past and it sounded just like it.

I'm lost

Kevin has tried an entire new inlet manifold, with injectors, fpr and fuel rail

[Marks DTM Calib]

So, lets try to pin point the cylinder.

Get it running and bung tech 2 on....cut the cylinders 1 at a time.

[Bent valve]

So, lets try to pin point the cylinder.

Get it running and bung tech 2 on....cut the cylinders 1 at a time.

The 'hi tech' version of pulling the plug leads one at a time

[Kevin Wood]

So, lets try to pin point the cylinder.

Get it running and bung tech 2 on....cut the cylinders 1 at a time.

The 'hi tech' version of pulling the plug leads one at a time

.. and I wish I'd remembered it before stripping it down to look for lifter problems.

Kevin