The Siberian Patrol is down :( Please help!

Mates,

After returning from a 1300+km round trip on our winter roads, my engine has started detonating (I think) pretty severely.

The day after I returned (and the Patrol ran perfectly on the trip), we had a cold -30C morning and I had trouble starting it. After getting it warmed and started I took off to run some errands and not more than 2 stops later and 10 min of runtime, the engine started detonating and grew progressively worse to the point that I couldn't drive it.

I parked it and after consulting with a mechanic here, I loosened in turn each fuel supply line at the injectors and started it to see if I could isolate which cylinder and injector was the problem. Nothing conclusive as the sound still remained through each step, although maybe slightly dampened when loosening the #4 and #3 fuel lines.

https://vimeo.com/202151527

What the engine sounded like.

Sent the results to my mechanic friend (in the city - I am in the village without a diesel mechanic here), and he was still certain it was fuel injector related, so I pulled all the injectors for a closer look. Found a considerable amount of carbon deposits on the tips of the #3 and #1 injectors and in the combustion chamber so it appeared that those 2 injectors were overfueling and causing detonation.
http://www.nissanpatrol.com.au/forum.../2017/02/7.jpg

So I bought all new injectors and sent the old ones off to be rebuilt. Yesterday I installed the new injectors, hooked everything back up and started the engine and...nothing changed. Still detonating even with all new Bosch injectors. Here is another video clip of the engine sound yesterday. Obviously nothing has changed. Could only get one video to upload, so look at the first one. Sound hasn't changed.


I am now at a loss. I am considering pulling the fuel lines at the filter and running a can of diesel flush through the system if I can find some up here, or buying some fresh fuel and doing the same thing to see if a clean fuel source will make a difference.

Other than this, I am completely lost. I am open for any and all suggestions. Does this sound like a detonation problem or does it sound more serious?

And just for the record again, I have a 1999 GR RD28T with a mechanical IP and a completely rebuilt engine 1 year ago and less than 30k km on the rebuild.


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Working on getting the videos up. Sorry about that.

Video up!


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Can you tell if the tap noise is coming from the front or back of the motor? Injector pump or injector pump timing? it sounds mechanical maybe even a dropped valve or somthing. Hard to tell on a recording. I had a similar noise on my 3 ltr but not as bad. Turned out to be the end of a glow plug had dropped into the cylinder and bounced around on the top of the piston. It wasn't that noisy though.

Could it be a stuck valve lifter ??
It sounds too consistent to be something loose rattling on the inside.

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Quote:

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Originally Posted by 4bye4

Can you tell if the tap noise is coming from the front or back of the motor? Injector pump or injector pump timing? it sounds mechanical maybe even a dropped valve or somthing. Hard to tell on a recording. I had a similar noise on my 3 ltr but not as bad. Turned out to be the end of a glow plug had dropped into the cylinder and bounced around on the top of the piston. It wasn't that noisy though.

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Can't tell front or back but it is definitely a top-end sound. Maybe a valve or lifter but I pulled the valve cover off and everything seemed tight with no play.


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Quote:

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Originally Posted by Hodge

Could it be a stuck valve lifter ??
It sounds too consistent to be something loose rattling on the inside.

Sent from S5

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I agree that it doesn't seem like something loose rattling around. It is a very consistent sound and increases/decreases with engine RPMs but the intervals stay the same. How would I check if a valve is stuck? I pulled the valve cover off one time and looked but wasn't quite sure what to check.


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It doesn't sound like a fuel system at all, I'd remove glow plugs to see if they're complete, and if you can do the compression test.

The knocking sound indicates something mechanical, has the timing belt jumped a tooth out so if piston is hitting a valve...? I'd make sure valve clearance is correct as well.

Does the engine smoke? blueish or greyish?

The noise sound very much like either big end or piston knocking but from the video the engine seems to run smoothly so isn't something like rotating outside being hit e.g flywheel bolt/clutch etc.

What happens when you de clutch?

Also can you narrow down where is the knock coming from, is it from the top, bottom etc. You can fashion up temporary stethoscope from long screwdriver which you can point against the engine section and by holding it where part of you hand/palm protrudes over the handle and act like cup you can put your ear against. You should be able to hear clearer where is that knocking sound coming louder from.

Regards

Attachment 70814

Quote:

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Originally Posted by Rumcajs

It doesn't sound like a fuel system at all, I'd remove glow plugs to see if they're complete, and if you can do the compression test.

The knocking sound indicates something mechanical, has the timing belt jumped a tooth out so if piston is hitting a valve...? I'd make sure valve clearance is correct as well.

Does the engine smoke? blueish or greyish?

The noise sound very much like either big end or piston knocking but from the video the engine seems to run smoothly so isn't something like rotating outside being hit e.g flywheel bolt/clutch etc.

What happens when you de clutch?

Also can you narrow down where is the knock coming from, is it from the top, bottom etc. You can fashion up temporary stethoscope from long screwdriver which you can point against the engine section and by holding it where part of you hand/palm protrudes over the handle and act like cup you can put your ear against. You should be able to hear clearer where is that knocking sound coming louder from.

Regards

Attachment 70814

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Think I narrowed it down a bit. Definitely not fuel system as I ran some clean fuel through it today and no change.

Sound is coming from the front of the engine the 1,2,3 cylinders. Noticed that I have some bubbling under those injectors between the block and head. Looks like I've blown a head gasket.

Would that loss of compression result in the overfueling of those injectors and detonation?

https://vimeo.com/202174789



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I'm not sure, that would have to be the massive loss of compression to sound like that but anything is possible. To me it sounds like very metallic knock not compression one. TBH watching video is not the best to diagnose engine noises.

Sounds like loose tappet/valve to me.

RD28 are also notorious for vibration damper/harmonic balancer bolts coming loose especially on rebuilt engines where they're not torqued and lock tighted correctly.

Regards

I agree that the sound is metallic and a video isn't a good diagnostic tool. Seems like it's coming from the head somewhere. I'll check the harmonic balancer bolts today. Looks like I'll be pulling the head regardless, so I can check all the valve assemblies when I do that.

Valve, rocker noise is my bet.