Timing Chain Failures and Oil Filters

[lookskyward1]

That poll shows an spread through the earlier years but that could also be explained by age or distance "wear and tear" - doesn't make it right, the timing chains aren't supposed to have a "best before" date!

It still seems to be the case that it's not the chain failing, it's the tensioner.

As I said above Dave at Billcar (The No.1 UK YD25 independant specialist) has never known the lower tensioner to fail.

The same tensioners are fitted to the YD25 engine in the D22 and there is no problem with the ones fitted with the lower duplex chain (2001-2005). The problem is the single chain being used on a more powerful engine.

As for the poll and the age of the vehicles involved. The extended (hidden warranty) on the timing chain has no doubt given owners of newer vehicles a fall back and peace of mind should the chain fail within the warranty period.

There was a Kiwi that joined the forum who said he worked for Nissan and that it was caused by the EGR turning the oil acidic. He reckoned there was a software update to fix it but wasn't sure what it did. Here http://www.navara.asia/showpost.php?p=263491&postcount=38 and here http://www.navara.asia/showthread.php?t=17517

I blanked off my EGR valve at 80k miles.

 

[kernels]

So how impossible would it be to change the sprockets etc and put belts on a yd25?
Just out of interest...

No chance, timing belts run 'outside' the engine, chains run inside in the oil.

Realistically, the only solution is to fit a dual row replacement chain when the stock one needs doing. Budget $3k extra for (hopefully) somewhere past the 100k mark.

 

[Hatchy]

It's to much load on a single row chain. Should never have been designed like that. Single chain that runs hp injection pump and also drives the cams dual row chain. We have a customer that blocked his egr the day he got it only ever used genuine parts but changed his oil every 5k. Still had the death rattle. The bottom chain had stretched so much the tensioner was sitting against the crank sprocket. We fitted dual row kits claimed under warranty now has 450000km still going strong.

Also there are about 6 different yd25 motor variants iirc.

 

[Old.Tony]

So in summary:

* The upper tensioner is a possible weak point
* The lower chain is a definite weak point

Best option for preventing major damage is:

* Replace both tensioners
* Replace both chains with double-row (or better?)

Question: why not use a hy-vo chain? I had a hy-vo on my 1977 Bol d'Or (actually both the cam chain and the main drive chain were hy-vo chains).

Further question: Is the upper tensioner a weak point and what can be done to improve it, or was the experienced failure an aberration?

 

[Iceman]

That hyvo looks nice. Would a duplex one be available for the yd25?
This and upgraded tensioners should sort the chain issue!
If i was buying a new d40 i would say yes i will sign on the dotted line... If you put one of these in it first! Be interesting to see thier response

 

[Iceman]

Pulled apart a qd32 a little while ago and everything is gear driven. It had 300,000 on it and they were like new. It was a broken con rod that killed it.
Now why didnt they just use those bits for the yd25. Cheap and proven reliable. Every day i am more filled with doubt about 'progress' in car design!

 

[steel d40]

Just tossing it up there but another question might be manual vs auto.
Mines a manual and being a little lazy sometimes I may have let it "labour" a little in too high a gear at times. Sounds terrible when it happens, all rattle and shake.
Was also worse when stock and the motor was prone to falling into a no boost hole that needed revs.

 

[roscoe07]

I dont understand. I thought that the "non return valve" in the ryco would mean that the filter retained the oil and did not drain out.

 

[4 naving]

The non return valve is not as good as the genuine or different in some way and it allows oil to seep back out.
It seems not all non return valves are the same....

 

[roscoe07]

Where can you get a Hy-Vo kit for the D40 diesel?

 

[abouttogobush]

In reply to a few earlier posts in regard to the same tensioner fitted to the yd25 in d22 form and not failing as often due to the lower output as opposed to the d40, how is this possible?. The chain only drives the cams and pump, the horsepower difference is measured at the flywheel. Surely one can surmise the same strain is experienced by the chain in either engine variant. There are many properly "worked" d22's in yd25 form exceeding 150kw without a problem. Or am I still living back in the old pushrod day's?.
Cheers.

 

[camo.b]

According to baileys diesel group you tube vids its take a 15kw elect motor to spin up a diesel pump to max pressure. Fair constaint load!

 

[Old.Tony]

15kW is somewhere in the 20Hp region. That's a fair amount of power just to turn the pump over.

As for the D40-D22 differences, that's a good point. Perhaps the tensioners in the D22 are an older style (where perhaps not as many short-cuts were taken in manufacturing?) which is also more robust - who knows. Maybe someone thought it'd be a neat idea to replace the steel sections of the tensioner with plastic.

 

[camo.b]

If the d22 has no tchain issues why are we not running d22 when replacing?

 

[abouttogobush]

That's 20hp to run a pump Cam?, seems very high for a little 2.5, did the clip say what type of pump they were spinning up?, perhaps a Make truck lol
Cheers.

 

[camo.b]

Nah they were talking just everyday vehicle common rail pumps...ill see if i can find the link....

 

[camo.b]

http://youtu.be/kaga5cbOjns

 

[camo.b]

Here ya go....
Baileys diesel has some top products.

 

[glennm]

I had mine checked at 115k and there was a link showing signs of wear. Not a problem however the tensioner was showing signs of the spring weakening and Paul did a mod on it to prevent the tensioner becoming too slack and allowing the chain to flop around unabated. At around 140k i had it checked again and the number of links showing wear was up to 6. The original one a lot more than the others. Was over worrying about it and had the duplex unit put in. Paul said at the time the top chains he felt were good for 250k but i had him replace it all.
I have also given some thought to vehicles parked nose up/down/level. If there is a line of thought in oil delivery delays to the chains being an issue could this be a contributing factor? Mine seemed to be noisier if it was nose up overnight rather than nose down. Of course it could be just my imagination.

 

[roscoe07]

Bought nissan filter today. Deep Breath $30.00 Will change oil this week and see if filter changes anything. I already had a new Ryco and have them sitting side by side. different design Ryco has 8 inlet holes while Nissan has 4. Both have the valve behind the holes.