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Discussion Starter · #21 ·
Update on my situation: -
Car still off the road, that's seven weeks today. Massive backlog with local mechanics, car was only taken in two weeks ago, and today is first chance mechanic has had chance to look at it.
He called me in to look today. Top edge of timing chain cover pulled back, timing chain still on the top cog, but appears to be slightly loose, but that may be because hydraulic tensioners are empty of oil and guides are not pressing tightly against the chain because engine has not run for seven weeks.
He has removed the fuel injector system etc, but unfortunately there is no rocker cover that can be removed to look at the camshafts. The M9R engine has a rocker box which is quite deep and contains the camshafts. With injectors etc out, one of the camshafts is visible, nothing unusual. However the suspect camshaft that the mechanically driven fuel pump runs off cannot be seen without removal of whole camshaft box.
Next stage in investigation is to completely remove the timing chain cover to see what's going on with guides / tensioners and bottom crankshaft sprocket if anything. My timing chain cover has always leaked a little oil, so at least that problem will be fixed. The metal timing chain cover cannot be re-used, must be replaced with a new one because it gets trashed during the removal process. (I can explain that if anyone doesn't understand why, just ask)
If everything ok with chain / guides / tensioners, then I have asked mechanic to use a boroscope to attempt to look at the suspect camshaft and see if there is anything broken in or around the sprocket from which the fuel pump takes it mechanical drive.
For those who have not followed full story, the engine is currently locked up. Something is broken somewhere inside preventing it from turning at all now. It all started off with failure to start one morning without warning. We initially traced that to fuel pump not delivering fuel when engine cranking. We soon discovered that fuel pump on the T31 M9R X-Trail is not electrically powered, but takes a mechanical drive from a sprocket on one of the camshafts.
Fuel pump not turning, hence cam not turning, must mean camshaft is broken, or fuel pump drive sprocket broken, or as we first assumed, timing chain is broken.
Will update when more information becomes available.
 

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Discussion Starter · #22 ·
Not much update yet. Besides mechanic has prized back the top of the timing chain cover to find that the timing chain is still sitting on the top sprocket, however it appears to be very loose. Perhaps the tensioner is not functioning, will await further details. Chain may have slipped a couple of teeth on the crank shaft sprocket when I hand cranked the engine in the wrong direction. This could explain the engine locking up in both directions now, ie. valves hitting pistons. I wonder if hand cranking is enough to damage valves in these circumstances?

Anyhow, still doesn't explain lack of fuel from pump.
 

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Discussion Starter · #23 ·
The cam box has been lifted off the engine to find that all of the rockers are broken, so something catastrophic has happened. It looks like the kind of damage one would expect to see from a timing chain failure but we know this was not the case.
The source of the problem is still a mystery. The timing chain was in place and is in good shape, with no visible wear. In fact the camshafts, cam surfaces, camshaft bearings, followers, camshaft sprockets and crankshaft sprocket for timing chain all look good, with no visible wear or other damage at first look. Inside of cam box and timing chain area are clean with fresh, almost clear engine oil and no visible black or any colour of other deposits, and no metal shavings. (Last oil change(s) had no visible metal either.)
Until cylinder head is removed and we see deeper inside engine, it is not possible at this stage to assess the full extent of the damage.
Initial assumption was that the timing chain had slipped a cog or two, but I'm wondering if the source of problem could be some other mechanical failure inside engine, will await further information.
Another mystery is that none of the above explains why there was no fuel being delivered from the fuel pump when engine was cranked after initial failure to start.
It does perhaps appear that the failure to start, ie. no fuel being delivered, may be an entirely separate issue to the above mechanical failure. So strange!
 

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Nissan X Trail Columbia 2.2 DCi 2006
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Rockers will have broken by valves being impacted by pistons. Common failure on this engine. In such an extreme failure, piston, con rods and crankshaft and bearing damage can be expected. Normal cause of such a catastrophic failure would be timing chain failure, again common on this engine. I would suggest more thorough investigation.
 
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