Adventures in Timing Chain.

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there not on my page 2 of this thread. i see them in your pics on the other link. hey have you blocked the EGR ? looks like alot of soot in the open egr unit in pic.
 
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I have the Engine Australia (strange thing, I paid $830 to my door :/ ) kit sitting in the shed, with my Nav up on blocks ready to do this. To say I'm apprehensive would be an understatement.

I've been procrastinating by replacing brakes. I'm even having issues there, with rotors and drums corroded on tight.

There are a lot of faults on this truck from earlier owners that I need to fix up.
 
My Engines Australia fitted Timing Chain lasted 25,000km.

Tensioner failed, wore through the guide and sounded like i'd done a Big End such was the noise.

They would happily supply a new kit, but i'd still have to pay labour to fit it. I passed and went with a whole new supplier and 30,000km later it's still as quiet as a mouse.

Nice work on doing it yourself. We attempted it first time but, like you, could not get the balancer bolt off. after 3 hours we gave up and I sent it off to and engine builder whom had to use a blow torch on it - they had nothing that would get it off otherwise.
 
Update:
No issues to report. No oil leaks either (yay).
That bucket of bolts noise at start is no longer a thing.
Trouble free trip over Easter up to Whitfield/King Valley (with family and camper trailer loaded) with some ~120K of 4x4 around the top of Cobbler/Staircase etc.

Other observations - during and since:
Non-stock oil filter is stone cold empty at start up. This would explain the tensioner taking a while to kick in.
When I change out the current genuine filter, I will cut it up to see what it's got inside.
I have set a mental schedule to pop the top timing cover off this time next year to see how it's going in there.
The oil inlet into the tensions is a very small hole - I would estimate less than 1mm - and I suspect very easily blocked if the vehicle is not maintained.

More generally...

It's probably no surprise to anyone here - but the venerable D40 is VERY common. I walk along a busy (3 lanes either way) main road in Melbourne's east 5 days a week (7AM) to get to work - about a 600 meter stretch. It's not uncommon for me to count 6+ D40s passing. I know that not all of them will be YD25 powered but I think that is safe to assume that the vast majority of them are. That's also not including D22s - nor R51s, nor the new shape D23s. There is always going to be something to be said about fact that the more there is of something, the more of them there is to stuff up - for any number or reasons. Now I know that based on that extrapolation you should see at least 20 GM/Buick 3.8L V6 powered Commodores on the side of the road daily - maybe it's not that many - but that engine has evolved over the last 55+ years, versus less than 20 for the YD25/22 - and I don't believe that all applications of this engine are considered to be weak in this regard. But in this day and age is that an excuse or justification? No.

Am I saying they get a bad wrap? Maybe. There is no question that it does happen and some people have been frikkin unlucky - case in point is Czechmate with popped chain at a young 70,000K - all the while doing the right thing.

There is no doubt a stigma is firmly attached to these vehicles/engines at least some of which (perhaps controversially) is a result of what I think is a self-perpetuating snowball of FUD (Fear Uncertainty Doubt). It tends to collect in places like this. Has there been any solid analysis (or estimation even) done of the number of failures per 1000 vehicles? No (nor is it likely). Would that data show anything of significance? Maybe. At what point would it be significant? 5? 10? 50? Do people who have had it happen to them gravitate to forums like this? Absolutely (lookup confirmation bias). Do D40 owners who run a trouble free D40 come to these places? Maybe, but nowhere near as likely - and probably for different reasons but end up getting caught up in it. Do some people (none of us here clearly) simply not look after their vehicles at all or as they are supposed to - and then wonder why? Yes - categorically. Are there lemon engines and unlucky people? Yes. See above.

Based on the condition of the old timing chain/guides I pulled out of my engine, they simply did not need to be replaced. Did the oil filter have something to do with the racket at start? I am 99.8779% sure it did. Could a tensioner have been a bit tired and not kept tension up well enough without that quick oil pressure? Likely. Am I just lucky? Maybe - but again, the FUD would more or less stipulate that I should have found a whole lot of nasty in there and it should not have been a surprise to do so. And I think this is an important point to highlight.

Is the level of FUD justified? All evidence, really, is anecdotal. Am I a victim of that FUD anyway? Yes - as I suspect a lot of others who have been down this same road might be as well. But, as I am now and others before me and others to follow will attest to - having done it gives one a sense of relief. No need to worry about it - which is just fine...

Anyway, take this as you will - constructively. I'm not out to get up anyone's nose. I'm just being pragmatic. From someone who bought one. And spent a weekend up to his elbows in crappy black oil and gunk from one....
 
Tensioner failed, wore through the guide and sounded like i'd done a Big End such was the noise.

Pretty much the exact symptoms that convinced me to take my truck off the road. Found this when I opened her up:
 

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Aaron
Well said
From my experiences I learned that the 07-09 spanish built stx d40s have a yd25 with a wrongly specified french made timing chain known to be more prone to failure than all other yd25s in other nissans
Simply an under-engineered part for the loads applied to it
All other yd25s are as likely or unlikely to fail as any other timing chain driven common rail diesel engine

My local garage worked with me, with the help and parts from Paul from yd25.com.au, to fix my bus when the chain snapped

This garage has also repaired busted motors from snapped chains in 3 litre isuzu powered holden colorados

Common rail turbo diesels put out a shite load of torque for the size of the internals and drive train, which makes them likely to go boing when pushing a large vehicle at speed
 
This has been a very informative thread, Aaron well said mate. I'm suprised the Isuzu has had problems that motor has been highly regarded. At the end of the day the chain is only driving the cams and the pump so you would think the load would be not too great. Always heard Paul at YD is a very helpful fellow too.
 
Cheers all.

Again, if anyone is looking for some moral support in DIYing this job in Melbourne's east, let me know.

Looking at those pics from Murph289, I (at least) have a new level of respect for the lower chain!

My theory is that the tensioners were pushing up far too hard - could it have been the bleed out of the lower tensioner was blocked? Either that or the lower GUIDE was basically made out of flour and water (or the crap quality aluminium equivalent) - but I think that is unlikely.

Either way, the fact that the chain over a period of time (how long?) basically sawed through that lower guide to the extent that it did should give people some level of confidence in that its not made of cheap chinese pig iron - at least.
 
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I have been following this problem for years and think we've finally got the reason why these failures occur. Mostly everything has pointed towards exactly your findings. Good work Aaron!!!.
 
^ Agreed, John. We even tried a poll of oil filter choices in case there was something in the non-return valve in some oil filters but that was very indecisive in the end.

We did get the impression that the tensioners were more likely to be responsible, but what didn't (and still doesn't) make sense is why the replacement tensioners are still standard Nissan tensioners - even in the double-row chain kits. Although, now that I put my mind to that, maybe it was a particular source within Nissan for the tensioners?

At any rate, an excellent thread.
 
The genuine nissan tensioners in my double row kit from paul at yd25.com.au were made in japan, and were slightly different to the ones that came out
I think the oil channels on the back of the tensioner itself were different

07 spainbuilt stx
 
Awesome thread.
just about to do my timing chain, bought a yd25.com kit off lubeup.com.au's website.
so thanks for all the info :)
 
Cheers all.

Again, if anyone is looking for some moral support in DIYing this job in Melbourne's east, let me know.

Looking at those pics from Murph289, I (at least) have a new level of respect for the lower chain!

My theory is that the tensioners were pushing up far too hard - could it have been the bleed out of the lower tensioner was blocked? Either that or the lower GUIDE was basically made out of flour and water (or the crap quality aluminium equivalent) - but I think that is unlikely.

Either way, the fact that the chain over a period of time (how long?) basically sawed through that lower guide to the extent that it did should give people some level of confidence in that its not made of cheap chinese pig iron - at least.
Couple more photos for interest.

The missing tension guide was found in about 20 pieces in the bottom of the sump.

I will own up and say I drove this for far too long after initially noticing the rattle, chasing all other options before finally accepting it as a timing chain issue. Denial I guess.

The final straw was a sound very similar to a bottom end knock, which I believe was the chain rapping on the rear timing cover. That happened about 20km before I put it in the shed and pulled it to bits.

Lesson learnt. Don't put this shit off.

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Sent from my SM-G935F using Tapatalk
 
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Has anyone else had an experience like mine where there was absolutely no rattle or other sign of problems and the chain just clean snapped?

It was ridiculously early in the engines life 70,000k

2007 d40 stx
 

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