TD42 - Damn clicking noise - not tappets

[chrispy]

Hey there all

I'm sufferring a clicking noise that is coupled to the engine's speed. If I was to hear it for the first time I'd say it was a dead hydraulic lifter. Only problem is that the TD42 is full of tappets, not lifters. The other problem is that I've adjusted the tappets to 0.014" as per the book (engine warm-hot) and it's still there.

What else could cause this noise? It's impossible to hear it when you've got your noggin under the bonnet.... as it only seems to appear when the engine is under load and driving along. Could it be something in the VE pump?

Cheers blokes
Chris

[bogged]

Injector /pump knock I think has been mentioned before as a noise like that

[chrispy]

Yup...thanks bogged. I just saw it mentioned in another thread - don't know why I couldn't find it before.

I'm taking it to the boys at Cooma diesel. They'll sort it out. $860 for a complete injector service and pump clean..... not the full re-build. I'll see what it does.

Jeez them's a set ot teeth you have.

[bogged]

Yup...thanks bogged. I just saw it mentioned in another thread - don't know why I couldn't find it before.

I'm taking it to the boys at Cooma diesel. They'll sort it out. $860 for a complete injector service and pump clean..... not the full re-build. I'll see what it does.

Jeez them's a set ot teeth you have.

how many klms on the truck now? Probably worth gettin pump done anyway

[chrispy]

306,000

The pump was last done at 180k... so it's probably in need of a real going over now. It's allright - I'm worth millions. This won't hurt a bit.

[bogged]

It's allright - I'm worth millions. This won't hurt a bit.

Take KY with you.. it helps

[chrispy]

It's allright - I'm worth millions. This won't hurt a bit.

Take KY with you.. it helps

LOL!!

[Woop]

Can also be worn valve rockers--usually when this happens, adjusting valve clearances is difficult.

Nick

[mrbonk]

Chrispy, can I ask how you went with this?

I have exactly the same noise in my TD42 GQ Patrol. It's kind of like a continual 'ticking' noise, which is relative to revs, but gets a lot louder when I back off the throttle. Apparently the pump and injectors have been 'done', but I'm not sure at how many kms.

[chrispy]

Chrispy, can I ask how you went with this?

I have exactly the same noise in my TD42 GQ Patrol. It's kind of like a continual 'ticking' noise, which is relative to revs, but gets a lot louder when I back off the throttle. Apparently the pump and injectors have been 'done', but I'm not sure at how many kms.

(MrBonk - I sent you this in a pm too)

Nope - I had the injectors and VE-pump serviced. Number 6 injector seemed to make a loud banging noise on every injection - you could hear it via a stethoscope. Even though that particular noise is now far quieter after the service, the same overall clicking niose is still there.

I reckon that the last time I had my tappets done, they did them cold and may have stuffed it up. They claimed to know what the different cold clearance was - in comparison to the 14 thou hot clearance, but you never know. The noise seems to have gotten worse after that last adjustment. If it weren't so time-consuming to remove the DTS turbo plumbing and all before the engine cooled down too much - I'd have done it myself - which I'm still thinking about.

I'm now thinking that the pushrod ends have worked spherical holes into the bottom of the tappets after 310,000km. If this were the case, irrespective of how they set the tappet clearances with a flat feeler gauge, the spherical holes would still offer more play than that. I'm going to have the entire timing system removed and each of the tappets ground flat on the bottom to remove the wear holes. I'll then get them to set it up cold, fire it up and then get them to re-set it per the book - i.e. 14 thou when hot. This is fine, accepting that the rocker bearings could also be stuffed.

If that's not the problem... then I suspect that what I was told by a diesel mechanic some time ago to be true..... where Nissan had often not matched pistons to liners and there is a certain amount of slap built in as a consequence. It's meant to dissapear when the engine comes up to temp, but I have a viscous clutch problem with my fan at the moment where it refuses to slip at high revs - keeping the engine too cold.

I suppose that when I fix all of the above over time, it might get back to being a quiet engine.... here's hoping!

[mrbonk]

Nope - I had the injectors and VE-pump serviced. Number 6 injector seemed to make a loud banging noise on every injection - you could hear it via a stethoscope. Even though that particular noise is now far quieter after the service, the same overall clicking niose is still there.

I reckon that the last time I had my tappets done, they did them cold and may have stuffed it up. They claimed to know what the different cold clearance was - in comparison to the 14 thou hot clearance, but you never know. The noise seems to have gotten worse after that last adjustment. If it weren't so time-consuming to remove the DTS turbo plumbing and all before the engine cooled down too much - I'd have done it myself - which I'm still thinking about.

I'm now thinking that the pushrod ends have worked spherical holes into the bottom of the tappets after 310,000km. If this were the case, irrespective of how they set the tappet clearances with a flat feeler gauge, the spherical holes would still offer more play than that. I'm going to have the entire timing system removed and each of the tappets ground flat on the bottom to remove the wear holes. I'll then get them to set it up cold, fire it up and then get them to re-set it per the book - i.e. 14 thou when hot.

If that's not the problem... then I suspect that what I was told by a diesel mechanic some time ago to be true..... where Nissan had often not matched pistons to liners and there is a certain amount of slap built in as a consequence. It's meant to dissapear when the engine comes up to temp, but I have a viscous clutch problem with my fan at the moment where it refuses to slip at high revs - keeping the engine too cold.

I suppose that when I fix all of the above over time, it might get back to being a quiet engine.... here's hoping!

Well, bollocks to that......I was hoping to have a relatively easy (albeit potentially expensive) fix for it. I may have to just learn to ignore it and pretend it's not there

I think I'll have a go at tappet clearances myself. The rocker cover *has* been off this thing (the evidence of some sort of blue silicone along the gasket line is a giveaway there), but again I have no idea of how long ago. Thankfully, it doesn't appear to be too difficult a job for me (it's non-turbo).

[bazzle]

Nissans get a lot of wear in the rocker shaft area. Normally due to wrong oil used.

If it is happening when you accel i may be an injector but also may be an exhaust leak.

If you can hear it at idle then more likely just a clicking inj (prob OK if engine runs ok) or a top end noise.

These motors do click a bit and it doesnt seem to affect to much.
To check inj just crack off at idle to see if noise changes.


Bazzle

[GutSquisher Media]

It could be a couple of things the first is the tappets are worn (they develop a hole where they contact the valve tops), or the rocker shaft is worn.

In your case would say its a combination of both, the tappets can be reground if not too badly worn the rocker shaft needs to be replaced, new cost is around the $150 to $200 mark from Nissan

[chrispy]

Bazzle, GutSquisher - thanks. I'll get the tappets re-ground and the shaft checked. I presume that with a new shaft I'll have to oversized??

Cheers
Chris

[mrbonk]

Mine seems to reduce when I put the foot down (although it could also just be masked by the increase in 'other' noises when I do that), but it most definitely increases when I back off the throttle. It's loudest when I'm travelling at 100kmh+......below that and the noise is neglegible.

[GutSquisher Media]

Bad news on the rocker shaft they only come std size no OS listed in Nissans parts program. But you may be lucky I replaced mine at 450k's with wear of 1.2mm on the shaft with no wear in the tappet hole.

Just measure the tappet bar hole and don't do what I did and reassemble the tappets in the reverse order, it's a bitch having to pull it apart twice.