Engine rattle on load / acceleration -Mostly solved!

Sounds a bit like the sound on older cars when vacuum advance on the ignition was wack. Like the early ignition makes the valves rattle. Going up hill or acceleration makes the noise come, [strike]mostly on low revs[/strike]. Edit: not so anymore.
The engine is a Liana 2008 VVT. Car is 2005 VVT. Has been running great since easter, haven't been noticing the sound before last two weeks. No fault codes.
Any suggestions? Sensors? Spark plugs? Vvt thingy?

Edit:possible solution below:
2008 Liana engine got 11.1:1 compression rate while the 2005 Jimny got 9.75:1 compression rate. Using the 2005 ECU with "wrong" compression rate will have ignition timing a bit off making the valves rattle. Changing to higher octane petrol lessens the intensity of the sound and it does not come so often.. More permament solution could be remapping the ECU, changing ECU to Liana or "other".. For the time being I am filling 98 octane, and will look into using octane booster additive possibly.

Edit 2: now experiencing diminishing power as well. almost as little power now that i had with the m13a engine

Edit 3: Changed the cat converter to one with better flow. old one probably restricted. Removed cat 1 in the manifold some time ago, and changed the second one now. Power is definitely back, runs great!
Using 98 octane i can hardly hear any ingition ping at all. Slightly more on 95 octane but would probably not notice it if i was no aware of it.

I Recommend to anyone with these problems to check or change the cat.
I have no idea if I will still pass the emissions control at my MOT next year but I'll deal with that when time comes.

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Been studying the noise more, and now it is mostly around 3000rpm and above 5000. Only when engine is loaded, only when warm. Seen and heard videos of cam drive chain rattle, and it is not like that. Local garage couldn't help me, has not had any such problems with suzuki engines, but some on Honda..

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Check the heatshield on the catalyst beneath your feet. When this first starts to come loose you get a tinkling noise, when it detaches on one side it sounds like you are dragging a load of scrap iron chains from the back. Only does it on load too..

facade wrote: Check the heatshield on the catalyst beneath your feet. When this first starts to come loose you get a tinkling noise, when it detaches on one side it sounds like you are dragging a load of scrap iron chains from the back. Only does it on load too..

will of course check this to rule it out, but have had similar loose heat shields before and this is not that kind of sound. more like some solid pieces of metal meeting up to give me trouble..
There is an extra spring on my catalyst as well to keep it silent. could have come loose, but nowhere near the same sound last time it did.
No sound when revving standing still either.
But load and warm condition could point towards exhaust as you say..

Hoping to get time to check both underside and beneath valve cover today..

Checked heat shield. Still welded to the pipe in both ends and with the spring around it. No such sounds there. did not get to looking under valve cover yesterday as i was doing other stuff to the car. Did another listening run and still the same: No sounds when cold, but on load when warm. Google and other experts has revealed no real solution or alternative.

Looks like the VVT sprocket/wheel/actuator is a hydraulic device.(?)
Does anyone know how this item works?
Is there a solenoid valve or something i can check the function of?
Still got my M13 engine i can swap parts from.

The vvt is controlled by the solenoid valve located horizontally at the top front of the engine, below the water elbow pipe.
There are 2 oilways in the sprocket end of the inlet cam, fed from this valve.
The cam sprocket is loose and attached to a 3 chambered cylinder , and there is a 3 spoked impeller on the end of the cam that is inside this cylinder.
With no oil pressure the sprocket rotates until the impeller blades contact the chamber walls, and the cam then rotates retarded so the engine starts.
When there is oil pressure, the ecu requests a specific timing advance or retard, and moves the solenoid valve one way or the other, to allow more oil to get between the impeller blade and the chamber wall on one side, forcing the cam to move relative to the sprocket.
The solenoid is operated at a high frequency, and the impeller blades end up locked solid with oil on each side of the chamber (or the cam would shoot forwards as the lobe goes over the tappet)


This is the general idea, this is actually a Delphi system, but I believe the jimny is the same





I can't see that rattling tbh, unless there is a massive oil leak at the front of the cam, and I'm fairly sure the erratic cam timing would put the EML on.

Renault use a dreadful thing called a dephaser pulley, full of springs, that does a similar job, except it breaks straight away, and rattles like a diesel engine.