TDCi DW10 Engines: Cam Chain Oil Supply

[AlCan]

Hi Guys,

A while back AlanM and I touched on the reliability of the inter-cam timing chain when subjected to poor maintenance. Apparently, if (oil changes are) neglected, it is prone to early severe wear, perhaps in some (2.0?) TDCi engine variants more than others. Now I'm wondering, why the chain, in particular?

Can anyone comment on this, please?

I recently bought a 2013 MC Wagon (TXBB? / DW10C engine), 133,000km.

The first time I started it after buying it - after it had been sitting for a while - I noticed that the cam chain was quite noisy. I noticed this again the next time also, when I was showing it to a friend and just figured, we've got a worn chain.

However, this time, while we were standing chatting in front of the idling engine - bonnet open with "beauty cover" off - I noticed that the chain was suddenly becoming quieter. It continued becoming quieter and quieter until it was barely noticeable. This took maybe half a minute - after already running for a minute or two.

Clearly, it was suffering from either lack of lubrication, or lack of tension - or both. Based on this observation, the oil flow to either the chain or (maybe?) the tensioner is very limited - maybe almost blocked?

My question for AlanM or anyone who might know: what does the Oil Supply to the cam chain consist of? Is it a small-orifice jet or spray, or is it merely splash from some other source? What's the chain tensioner situation - is it oil pressure driven? I suspect from watching an Alan Howat video that it is, but I don't think it was confirmed in the video.

The next question: what would it take to clean / fix it?

Any suggestions, please?

[Citroënbender]

Start by looking at parts diagrams for the valve train, to identify related elements. That will show if (for example) there is an hydraulic tensioner or filter screen before one.

Then you can look up the elements using part numbers and Google Images or Fleabay, to get a clearer idea of how they are in real life. The frequency with which a valve train element is offered for sale (like the BMW N46 models for which you can almost buy timing chains at the corner shop) often is a clue about component longevity or reliability.

For example:

https://www.ilcats.ru/peugeot/?funct...4A&language=en

Then you look up part 084922…

https://www.google.com.au/search?q=peugeot+084922

(I didn’t include the Google Images link as it was chockers with identifiers.)

In this instance, there doesn’t appear a huge market for link chains and guides, tensioners; this leads you towards the notion they’re fairly durable.

There is a sprung ball check valve, Peugeot number 023527, between the block and head (these normally are pressed into the head). It’s found on the pages detailing head gaskets etc.

[AlCan]

Thanks Citroënbender for your most helpful reply!

These Russians, eh? Often, they seem to know more than anyone. I watched a Russian YouTube Video on an MPS6 teardown - excellent, despite the auto-translation not being that great.

You have prompted me to dig further into the Tech Resources section and finally have found the MC Mondeo WSM https://www.fordforums.com.au/vbport...articleid=1882- but haven't figured out how to drive it yet... Some of the "links" don't seem to work? Haven't yet got to the section in question.

Yes, it seems like cam chains etc are not a commonly failing item - except where as AlanM suggests, maintenance has been neglected, which is sounds like it has in the case of this engine. Of course, I'd like to see if I can stop this problem before it gets any worse, and I'm suspecting partially blocked or gunged up somewhere there. I guess once dirty oil gets into the tensioner, it's hard to get it out?

[Citroënbender]

Chain tensioners of fifty years ago, often used to have a mesh filter screen - wouldn’t be surprised if this detail is long gone.

Excepting the polymer tensioner shoe, the rest of a unit can usually be dismantled and solvent cleaned off the car to restore function. Ones with a strong spring element (that moves quite a bit) may suffer ageing of this part, but most designs are simply to take up progressive slack - not large fluctuations like a serpentine belt tensioner.

Always worth familiarising oneself with how to retract and then release pre-tension in hydraulic units, at least these are a simple grenade pin type.

[AlCan]

I found a 6-year-old video by Alan Howat (he looked so much younger then) that covers the whole thing - more or less. He's quite funny, ol' Alan.
https://www.youtube.com/watch?v=ewV0i9MqMb8

It looks (and as he makes clear!) like quite a mission to replace that chain - far better to just change your oil on time, like he says. There is also a very helpful comment in the Comments (where else!?) by @Sergiu_K about not getting any sealant down the hole that feeds oil to the cam chain tensioner.

Although Alan doesn't mention it, it's pretty clear in the video that there's a hole in the bottom of the tensioner "foot". This, surely, is the hole that supplies oil to the chain itself. Since it's coming out of the tensioner plunger, it must be fairly small, so as not to drop the pressure inside the tensioner cylinder, but whether my partial blockage is there or upstream of the tensioner...

The link again
https://www.youtube.com/watch?v=ewV0i9MqMb8

Although it's apparently (Windscreen sticker) not due for an oil change, I think I'll do that first and see if it helps.

Oh, regarding the TechResources WSM - it looks like the way to navigate it is to find what you're after in the Index, then go to that section then manually scroll down the page (or search by section) to find what you're after. There's a lot of great info in there, but the Alan Howat video is the best overview.

Thanks CB for your excellent insights.

[AlCan]

Hole in foot: Alan Howat vid at 3:34

[kevino]

Wouldn’t worry about it.
Had a Ford tdci 2 litre sold it at 278000kms
Never was the quietest engine at start up
All those Ford engines even petrols (Refer to Euro s) noisy on start up then quieted
Of that era.

You can keep driving those engines till the wheels fall off

Also they are a shared Peugeot - Ford design - I had the chain tensioner replaced at 180/200000 what ever the book said - by a Peugeot specialist.


Franco Cozzo on here had one too and his with another owner and neglected is over 250000kms

[AlCan]

Originally Posted by kevino

Wouldn’t worry about it.

Thanks! Would love to be able to take that advice!

However, I have a 2011, done 259,000km, one prior owner, fully maintained, no noticeable cam chain noise.

In contrast, the 2013, 133,000km but already 4 or 5 prior owners, (was cheap, but) probably badly maintained, already has this problem. I was hoping the 2013 would replace the '11 as that one has clutch/gearbox issues...

You know what they say - the best laid plans... But I was hoping the '13 would keep us on the road. I'm hoping that if I can get the tensioner sorted, it might be ok.

Oh, and, I've watched too many Alan Howat videos...! It looks to me like lack of clean oil causes these issues, and it seems, once it starts, it's one way.

[AlCan]

Originally Posted by AlCan

Oh, and, I've watched too many Alan Howatt videos...!

Like these:

https://www.youtube.com/watch?v=UBs1FLVyxdk

https://www.youtube.com/watch?v=aVFa8H1RpSY

https://www.youtube.com/watch?v=-jLzRoDQdyo

https://www.youtube.com/watch?v=08VYLAQ5xr0

It looks like the MD has many more cam chain issues than its predecessors.

The cam chain is a redesign, which on the face of it, looks like it should be good. It saves space by turning the tensioner the other way up, allowing an oil filler / handy cam chain inspection hole to be placed in the rocker cover, but this may be also be why it seems to fail so often.

In the earlier models, the cam chain tensioner presses down on the upper pass of the chain. This causes the chain to wrap further around the sprockets as it wears. However, the new design pushes UP on the upper pass of the chain, which has the opposite effect. I can't see that that's a big deal because either way, it's on the slack pass of the chain, and because the presser foot is facing upward, you'd imagine, if it's still pushing oil out through a hole in the foot, that this would lead to improved oiling of the chain, but they seem to snap more often. Maybe they reduced the oil supply at the same time, making it more prone to blockage?

However, when you look at the way the chain sits when the tensioner is not tensioning, such as at 7:48 in the https://www.youtube.com/watch?v=aVFa8H1RpSY video, you start to get an idea of what might be happening.

With the tensioner pressing on top, it's working in the same way as gravity. The chain will naturally hang down even if there's no tensioner, and the tensioner plunger itself will come to rest after a stop, hanging down on the chain after the oil has drained away. The spring inside it will ensure that too.

However, in the case of the tensioner pushing upwards, once the internal spring breaks, the tensioner will drop over time causing the chain to take on an M shape as per 7:48. It's easy to imagine that when the engine starts from cold with no oil pressure, the slack chain coming off the driving sprocket (LHS, [rear] exhaust cam) is going to crash into the side of the tensioner foot, and if it's a bit worn and stretched, it's likely to jam and be dragged between the tips of the sprocket teeth and the side of the tensioner. It can only break...

I would almost guarantee that's what's causing these chains to snap. I haven't surveyed it, but I'm willing to wager that snapped MD chains always have broken tensioner springs (first). And that they always break on startup, after a longer period of not running.

Howzat, Alan Howatt?

[kevino]

Maybe post on whirlpool automotive it’s a bit quiet on here unless it’s falcon- ranger- Everest

[AlCan]

Originally Posted by kevino

Maybe post on whirlpool automotive it’s a bit quiet on here unless it’s falcon- ranger- Everest

Very true, will take a look - not signed on there yet.

On this whole MD tensioner thing - the old brain is like a dog with a bone...

It's odd that Alan Howatt simply replaced that broken chain, tensioner etc without knowing what caused the chain to break. In the video with the split sprocket hub and the missing teeth, it's probably the same thing? In that case, you'd think there would have to be gouges or marks in the side of the tensioner to show what happened, if this theory is correct.

ANYWAY, another thought occurred to me.

This is going to depend on lots of things that I don't know about. Citroënbender mentions that there's a ball spring check valve in the oil gallery feeding from the block into the head. That's a good idea, to stop oil draining back from the upper oil passages during shutdown, but what if there are oil passages opening in the head, below the level of the tensioner cylinder? For example, oil passages feeding each cam journal. It looks to me that the cam lobes press downwards onto the rocker arms.

This means the cams are likely to be in a lifted position in their journals during shutdown, pushed upward by open valves. If the journals are worn, or the oil is fed into the lower side of the bearing, then oil could siphon out of the tensioner cylinder. It will be able to do this if there's (still) an oil passage feeding from the tensioner cylinder through the piston and out onto the tensioner foot. This drilling will allow air into the top of the piston & cylinder, allowing the oil to drain out somewhere lower in the head.

So, after standing a while (esp from hot), the tensioner cylinder could be largely full of air. Air, being of much lower viscosity than cold oil, on startup will simply jet out through that opening until the cylinder is completely refilled. No oil pressure will develop inside the cylinder until then. Since the inflow must be restricted, this could take many seconds - based on the time it currently takes for my MC cam chain to quieten down on startup. During that time, the tensioner will only provide spring tension - if the spring is still intact. If it's not, the tensioner won't provide any tension at all.

A Dangerous Time, given the jarring path the chain will follow leaving the driving sprocket. This all seems to be supported by the fact that in one video, the tensioner foot was broken off and the piston out of the cylinder...

So, MY SUGGESTIONS if you have an MD Diesel.

Keep an ear out for cam chain noise on startup.

If you hear it, or, maybe monthly regardless, with the engine Off - of course - look through the top oil filler hole and see if the cam chain is being held upwards under tension by the internal cam chain tensioner spring. If it's not, get a new tensioner fitted ASAP!

[Franco Cozzo]

Originally Posted by kevino

Wouldn’t worry about it.
Had a Ford tdci 2 litre sold it at 278000kms
Never was the quietest engine at start up
All those Ford engines even petrols (Refer to Euro s) noisy on start up then quieted
Of that era.

You can keep driving those engines till the wheels fall off

Also they are a shared Peugeot - Ford design - I had the chain tensioner replaced at 180/200000 what ever the book said - by a Peugeot specialist.


Franco Cozzo on here had one too and his with another owner and neglected is over 250000kms

I even bought the chain to have it replaced with the timing belt, and the workshop didn't bother replacing it

Mine was fine, car is still around with over 250,000km at its new home,

To put it into perspective, that thing survived me ripping skids in it on my Ps, hand brake up, clutch dumps, I put it down the drag strip 6x, towed overloaded 6x4 trailers with it and it carried tools around for me, thats how I treated that thing and the cam chain is still quiet.

She's a bit tired now though, last time I drove it, could tell some of the ponies have left but its probably 70%.

[AlCan]

Originally Posted by AlCan

I would almost guarantee that's what's causing these chains to snap. I haven't surveyed it, but I'm willing to wager that snapped MD chains always have broken tensioner springs (first). And that they always break on startup, after a longer period of not running.

EEeeee! Well, I got that wrong... Watched some of the video of the split cam sprocket hub again.

Having an intact tensioner spring is no guarantee that your MD chain won't break. So I guess the overriding thing is chain wear, which comes down to chain lubrication.

Franco - Thanks for your adventurous account! What a machine! Yes, I believe these engines are very durable and can take a thorough hiding, so long as the oil is maintained. Howatt's taxis have been getting much higher k's - equal numbers of MILES! Like I say, my 2011 engine has even more k's on it than yours, and is still going strong. Maybe 90% of its ponies still home. It even still has its original EGR valve still connected and working correctly (touch wood), so it hasn't had a lazy life. (Haven't tried disabling that one [no need anyway] as it has an ECU return signal so would probably throw the Mother-In-Law light...)

I've towed a fully loaded, covered 8x4 trailer to the South Island multiple times - it gets around 8l/100km on those trips but can still get 5.6l/100km on a trip through snow and ice in Tiptronic mode (without trailer of course). And the cam chain is still quiet...