Oil & Timing Chains?

[user 10312]

I've been thinking, yeah I know, dangerous.
But I have been wondering with the greater incidence of timing chain issues/failures on D40's. Perhaps the oil having somthing to do with it? Are the timing chain failures more prevailant on the D40's with DPF's fitted? i.e. the use of enviro oils.
Does the similar engine in the D22 have the same valvetrain?

I have been doing some reading up on oils and came across some interesting info.

Here is a few bits and pieces-

The question of phosphorus and zinc.
Phosphorus (a component of ZDDP - Zinc Dialkyl-Dithio-Phosphate) is the key component for valve train protection in an engine and 1600ppm (parts per million) used to be the standard for phosphorus in engine oil. In 1996 the EPA forced that to be dropped to 800ppm and then more recently (2004?) to 400ppm - a quarter of the original spec. Valvetrains and their components are not especially cheap to replace and this drop in phosphorus content has been a problem for many engines (especially those with flat-tappet type cams).

The US government mandated a 150,000 mile liftime on catalytic converters and the quickest way to do that was to drop phosphorous levels and bugger the valvetrain problem. Literally.

One of my readers found out when he went to buy oil for his (modern 4V common rail diesel) Nissan that they expressly prohibit the use of CG or higher rated oils. Nissan mandate that owners use CF oils in these engines. It's worth noting that the CF spec was already out of date when these engines were built but Nissan did not use the latest API spec because it wasn't good enough!
The fact that API have dropped the CF tests/standard does not in any way improve the later oils that do not meet this standard.

Read more: http://www.carbibles.com/engineoil_bible.html#ixzz2FRL2jAon

 

[180degrees]

You rarely see D22's with the problem, I have only read of maybe 2 that I can remember and there are more D40's with it however I beleive there to be more D40's running the YD25DDTI engine then D22's worldwide so therefore you will hear about more of them having problems. There are just so so many factors that any study into what causes it would be pointless IMO unless you had hundreds of control test cars running the same setups doing the same drives and getting serviced exactly the same ect.

Ideally nissan just needs to fit a stronger chain and tensioner though if it is infact a problem.

 

[tweak'e]

they didn't prohibit CG and higher rated oils, just CG rated. i suspect that at the time CG spec came out is that diesels where getting very clean and didn't need a lot of additives, which then was dropped in the CG spec. but high egr made diesels very dirty again and oils specs changed to handle that.

the only thing that bugs me is there is very few proper jap spec oils on the market.

the other problem that i think would effect oz more is using thick diesel oil. that generates massive amount of oil pressure when cold and may be putting to much pressure on the chain tensioner.

 

[Krankin]

And a low zinc or high zinc levels would not be the cause of the YD25 chain/tensioner failure....

1/ these types of chain/tensioner systems DO have a limited lifespan...tho ours is somewhat shorter and all over the place mileage wise and commonly fail in ALL makes of car and bike engines.

2/ The YD25 chain & tensioner system is PISSWEAK.


High zinc levels are especially good/designed for 'flat tappet cam' systems.

If you want good/high zinc levels in your engine oil....Penrite is the best
or for the older engines...Castrol Super RX.

 

[user 10312]

No DPF and run HPR 5 here.

Seems to run a little quiter than the genuine Nissan oil.

 

[seventies47]

Its the EGR function that causes soot build up and high acidity levels in the engine oil, this eats the chain. There is a ECM reprog available to combat this fault

 

[ST-R]

My understanding is that the D40 has a balance shaft and the D22 does not. Logic would say that driving this shaft puts additional load on the chain.

If this is true, I guess that is why the D22 seems less prone to the problem.

Regards

Greg

 

[seventies47]

Only the auto d40s have balance shafts, It is oil quality that causes the issue

 

[seventies47]

Sorry, only the 4wd models that have balance shafts

 

[Rumpig]

Its the EGR function that causes soot build up and high acidity levels in the engine oil, this eats the chain. There is a ECM reprog available to combat this fault

What is it the ECM reprogram does? Run the EGR less often?

 

[tweak'e]

My understanding is that the D40 has a balance shaft and the D22 does not. Logic would say that driving this shaft puts additional load on the chain.

If this is true, I guess that is why the D22 seems less prone to the problem.

Regards

Greg

i dare say most engines these days have balance shafts. zd30's do and no timing chain issues with them.

is it the chain that wears or the guide/plunger that wears?
the few pics i've seen show the guide worn through.

if its is an oil problem then a higher TBN oil would also help.

 

[seventies47]

Yeah it runs a different EGR strategy, probably less opening time. Also affects DPF regen strategy on equipped vehicles. DPF equipped vehicles suffer more from oil degradation unfortunately

 

[seventies47]

i dare say most engines these days have balance shafts. zd30's do and no timing chain issues with them.

is it the chain that wears or the guide/plunger that wears?
the few pics i've seen show the guide worn through.

if its is an oil problem then a higher TBN oil would also help.

2wd D40s do not have balancer shafts. the chain wears and stretches which causes over extension of the tensioner and contact with guides, Chain stretch is the primary fault

 

[Krankin]

i dare say most engines these days have balance shafts. zd30's do and no timing chain issues with them.

is it the chain that wears or the guide/plunger that wears?
the few pics i've seen show the guide worn through.

if its is an oil problem then a higher TBN oil would also help.

over the many yaers Ive seen this problem and on all different engines is....

it will always happen

the whole design is shite

95% of failures.... was due to the tensioner guide wearing out from the chain riding on it..WHY????? apart from the shite design of the overall system, prolly if you look at the the entry and exit angles re the chain on the tensioners...will give some insight

the worst were single row chains

yes...chain stretch and failure on single row chains only

and bad sprocket tooth wear..


A fix?????? ...oh thats TOO easy.............a GEAR DRIVE!