Who's right; PSA or Haynes?

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AlanS
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Who's right; PSA or Haynes?

Post by AlanS »

I don't know if I've just stumbled across a major boo boo by PSA or another monumental ballsup by Haynes, but when I pulled the engine down out of the TZi, a DKZ engine, I commented at the time that it appeared strange the way the rings were designed, very much akin to the old "Perfect Circle" rings of many years ago, where the oil ring was a one piece with a spiral stuck in behind and the top ring had a small piece taken out of the upper outer edge which (in the case of the old Perfect Circles) was there to allow for any lip at the top of the bore to prevent ring breakage. Second ring was just a normal square (cross)section ring.
The replacements had a taper on the inside edge IIRC which presented a full ring face to the bore.
Last night, I was scanning through a Peugeot 405 manual of Haynes, the blue cover version, and on page 2C*16 in illustration 17.10 Piston ring fitting diagram (typical) it shows a crossection of the side of a piston and rings and in it, you can see the one piece oil ring with the coil behind it, as ring #1, the square crossection ring as the compression ring at the top as #3 but it then shows #2 with the small cutout at the lower side of ring #2 which it also shows having a slight taper, so this would be what we used to refer to as a "scraper" ring. Set as shown in Haynes, I can understand the reasoning as it would tend to scrape any oil off the bore as the piston travelled down and force it back towards the oil ring but on our engine (untouched from when it left the factory as far as I know) this ring is located in the top groove and is facing the opposite direction with the taper going upwards and the cutout at the top.
It has often been claimed that the majority of these engines, particularly low mileage ones for their age were prone to using oil and I have heard it said that the Peugeot 205GTi did the same although some of them were taken in and repaired under warranty, so I wonder if this explains why this has been.
To my knowledge, the rings in these are the same as the ones in the 16V engine which might compound the mystery, unless of course, the TZis and the 16Vs were engine assembled in different places and one's made a blue which hasn't been discovered until it was too late.
Anybody else had an engine down and can remember this phenomena?
Too late to be claiming any warranty now, but handy to know if you own one and are going beserk trying to get it to stop using oil mysteriously as they do.


Alan S
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AndersDK
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Post by AndersDK »

No idea on the subject - except that I've just removed the exhaust manifold from a 19tri (monopoint) DDZ engine.
The beltmost exos port was 20% clogged :shock: by carbon and some white hard mass :?

The white deposit I'm quite sure is a mix of bonded tephlone particles and carbon sooth, as I've tried making this engine run quiter and with less oil consumption - using a "snake" oil containing tephlone.

This engine has run some 230K km, not a whole lot. But still it was a serious blue smoker when I got it. The tephlone has done its magic now : the engine runs much smoother and quiter, also the blue exhaust smoke has been reduced to almost nil, but it still has that nasty exhaust smell from a worn oil burner.
No doubt on the positive effects of this snake oil then, which I've used for years with very good results on hopelessly mistreated engines.

The thing to really note here, is the massive oil leaks into the exhaust on the 19engine, which IMHO can not be explained purely by leaking valve stem seals.
I've been running 2 different 16engines (one still a daily runner) which had even higher mileage - 320K km - and had some bad knocking from worn internals. But in no way a serious smoker like the 19tri.
This 16engine likewise returned very positive effects on the snake tephlone oil treatment, but no noticeable changes in oil consumption or symptoms.
Also a couple of swedish "motorheads" have tried replacing valve stem seals to get down oil consumption on 19 engines for MOT results. Results were disappointing - again on relatively low mileage engines.

That seems to support your obervations Alan.

Also note, that Haynes dont think. He copies what he gets from manufacturers and own observations on dismantling.
That would explain why Haynes haplessly in one case telling things to be upside down, in another case the same thing to be downside up - both being the truth, and the only truth.

If you dont get into deeply detailed discussions between Peug and Cit engine heads, no one will ever think about the oil rings issue as a problem. That would explain why the problem has never come up before - except that Citroen XU9 engines are known and accepted as oildrinkers, despite the fact that this is an unknown issue on 405 with exactly the same engines.
C U / Anders - '90red16riBreak - '91GrisDolment16meteor - Project'88red19trsBreak
dead cars : '89white 16RS - '89antrasitTRDturboEst - '90white19triBreak

AlanS
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Post by AlanS »

Thanks for the response Anders.

I've posted this on a couple of other forums with an expected "Huh?????" on one and the usual "valve stem seals are the problem" on another but the point is that over the years this problem has reared its head often and been explained as being valve stem seals, breather problems and a series of other ideas.
I've seen countless valve stem seals replaced with varying degrees of success or claims of success, even an elaborate catch can method suggested to get rid of the standard breather system, none of which have made sense to me.
The Tri engine 98 bhp IIRC has never had much of an issue and whilst it hasn't been a problem on 405 engines, it has on the 205GTi which run the DKZ (TZi) 122 BHP motor I understand.
Rings I believe are interchangeable between the standard DKZ engine and the 16V and I have a 16V engine almost apart in the workshop, so interested to see how the rings were fitted in that.
Spoke to a couple of engine men yesterday and asked the question and both agreed (without any prompting from me) that #2 ring is a "scraper ring" and should be fitted with the cut out pointing downwards on #2 groove and not pointing up on the top groove.
I'm hoping to get some confirmation from someone that they have stripped an original engine and found what I did just in case this engine had been pulled down before, although, I doubt any mechanic over here could strip and reassemble an engine without leaving a few tell tale marks somewhere along the way.

Alan S
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Doz
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Post by Doz »

16's will run and run until it hurts the ears to rev them!

Interestingly enough, the 16 engine in a pug is a smoker! The only major issue I had with 16's was it's ability to eat a camshaft every 100,000.

I wonder if it's down to cooling between the two cars???
Doz

2007 Citroen C1 (it's not a real Citroen)(With a complete set of wheel trims)
2006 C4 1.6VTR+ (Alloys no wheel trims)
1982 Mini HL (No wheel trims, no wheels)
1993 Kawasaki GPZ500

prm
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Post by prm »

Alan - this one has puzzled me.

Initially, I would presume your engine at some time, had been rebuilt/repaired, and the oil scraper – No 2 ring, had been fitted the wrong way. But most of the replacement ring packs are usually quite specific with fitting instructions.
But we can presume this engine is an OE build.

One theory??

I wonder if this ring configuration was PSA conforming to, or highlighting their emission levels, for certain global areas with new diesel (petrol??) vehicles.
Rings set in this way, I should imagine would initially, reduce the amount of particulate exhaust emissions from the lube oil (sump) contamination.
With new bores and oil rings, after the run-in period, the amount of oil carry-over should be at a minimum, enabling the scraper ring to be inverted.
No doubt., to see the warranty out at least.

You could try a claim. :lol:

I wonder how many smokers - valve stem seals and rebuilds, have been carried out due to this configuration, if this is the case.

Possibly, several components worked there way onto the 8v petrol side?

AlanS
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Post by AlanS »

Peter,

This is the point; I'm almost positive this engine has never been apart as it had full service records and was in the one family until we bought it.
It only had 90,000 klms on it when bought, but used oil right from when we got it.
Other TZis with low mileage also seem to have the same problem, yet the Tri, the lower horsepower model, don't do it and neither do the 16Vs and I've run 0W40 oil in my 16V for years and it never uses one drop between changes.
When I took the head in to the machine shop, the guy commented on the black goo in the ports and asked what I'd been using in it to get them looking like that. so I got the impression, this oil vapour had been passing through for a long time. It never displayed signs of oil burning such as blue smoke or an oily smell in the exhaust, yet a guy in Germany who I understand is a Citroen mechanic. claims on another forum to have never heard of such a thing happening, so I suspect it may have been engines assembled in a certain place, although that falls on its ear too when Anders is aware of it in Denmark as you'd have to suspect the Danish engines would be put together where the German ones were and LHD or RHD doesn't seem to make a difference.


Alan S
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jeremy
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Post by jeremy »

Alan - what's the bore finish like? Is there a heavy build up of carbon round the top ring?

This excerpt comes from a large book on diesel engine design I downloaded the other day
14.4.6 Bore polish
One of the most serious and difficult-to-overcome problems
regularly encountered in diesel engines today is bore polish
leading to early life loss of oil control. The polish arises from
the formation of hard carbon on the top land of the piston which
builds up to the point where it rubs against the bore under the
natural transverse motion of the piston and removes the honing
pattern leaving a polished region usually on the non-thrust side.
Although the local bore wear is small the rings seem to have
difficulty in controlling the flow oil in this region, perhaps due
to lack of conformability or character of the surface, and the oil
consumption begains to rise. This can happen after a period of
from 50 to 500 hours depending on the severity of the carbon.
If the top land is cut back by the order of 1 mm, the carbon is
of a soft form and readily flakes or breaks off but such cut back,
much practised in the USA in the past, is not acceptable today
because of the increased 'dead volume' and consequent higher
emissions.
Apart from the use of articulated pistons which do not have
the same high order of side load on the crown, two solutions are
in use in production engines today:
(1) A steel or cast iron ring is located at the top of the bore
projecting into it slightly in the region of the top land at
TDC. The piston top land is cut back to compensate for
this projection and there is no increase in 'dead volume'.
The 'cuff or 'carbon cutting' ring as it is called prevents
a build up of hard carbon beyond its inner diameter and no
polish can take place as the carbon is always clear of the
bore as it moves away from the TDC position.
(2) Ceramic particles are pressed into the bore surface in what
is termed the 'Laystall Process' and the resultant very
highly wear resistant layer is not subject to polish when
rubbed with the hard carbon on the land.*

The whole book can be downloaded from here:
(Under sub directory Diesel)

http://sitruuna.unk.fi/pub/korjausoppaat/

AlanS
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Post by AlanS »

No mate, it wasn't all that shiny, in fact, glazed bore was our first thought, but far from being glazed, this one actually had signs of wear, so I had to hone it fairly savagely to get rid of the lip.
I had previously given it the brake fluid down the plug hole trick as is done in Europe apparently and it gave it a really big boost in power which we suspected was due to freeing sticky rings, but the more people I ask, the more I'm convinced, some of these engines were assembled incorrectly.


Alan S
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AlanS
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Post by AlanS »

Well, I had some photostats arrive here last night from a guy I know who used to run a Citroen workshop, and sure enough, I was right; all the cut outs even back to CX and GS show the system as shown in Haynes with the cut out ring, the scraper in #2 groove and facing downwards, so perhaps it's a pity in many ways this wasn't noticed about 10 years back, in which case there might be a lot more Tri 122 and TZi models still running around. #-o ----^


Alan S
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prm
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Post by prm »

Alan,

I can’t believe PSA would make such a monumental c—k-up as that.
Fitting ring packs the std way is almost second nature with engine rebuilds

They must have known about this for some time. That’s the way to drum up new business.

I wonder if it was a disgruntled employee.

Do you think this all happened with one batch, at a set time, or over several months/years??

Found a few sites covering engines with inverted scraper rings but mainly on test bed applications and large diesel engines.

Also one site shows inverted scraper rings for military use. Why ?? - I don’t know.
Multi fuel application???

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Post by AlanS »

Peter,

There's been no rhyme nor reason to the ones we know of/suspect as having this problem.
I did hear once that they were "experimenting" with a different type of ring and was told the other day by a car wrecker I know that he thought is was done only in early Tri 122 applications (which is the DKZ engine) but hadn't heard of it in TZi models, yet I've constantly heard it about both. The thing that is weird is that it always seems that the problem is more prone on low mileage models than high mile cars.
Even more strangely, it is almsot unheard of on the low HP Tri engine.
It was also known about on the 205 Peugeots with owners reporting that they had their cars fixed under warranty and the handbooks "advised" owners that oil consumption was "acceptable" due to the design of the engines, yet the ones that didn't have the problem burnt none at all yet the ones that did found that 1 litre per 1000 klms was not uncommon.
Ours now burns absolutely ziltch so that story doesn't hold water.
It's pure speculation, but the fact it seemed to have lasted over such a long period and been so spasmodic, you have to wonder between slack quality control, experimentation or one particular shift that the factory manager for that shift or one of the assemblers had this idea that this was the way they should be done. It appears that Peugeot were prepared (begrudgingly possibly) to admit to a fault and if a customer screamed enough would rectify it under warranty, whereas Citroen just turned a blind eye to it.
I know of another TZi that is owned by a friend of ours that exhibits the exact same symptoms as ours did, so little doubt, it's a repeat dose of the same problem there.
The thing that initially "threw" me was that many years ago, 'Perfect Circle' used to produce a set of rings that were made with a step in the outer top section of the top ring to allow for any lip that may have existed in a worn engine and my initial reaction was to ask why a ring designed for worn engines would be used in a new one. It could also well be that someone in the engine assembly also remembered this style of ring and fitted it as you would one of the earlier ones not realising that this ring, unlike its earlier counterpart, had a gentle taper to its outside edge.


Alan S
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prm
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Post by prm »

The heavy oil consumption on the low mileage ones would make some sense, as the ring to liner spring tension should still be relatively high. Dragging oil/oil vapour upwards.
Citroens way of inducing upper cylinder lubrication.

No doubt ounce the thin contact area had rapidly worn away you would loose some of upward scraper effect, which would then turn into a worn No 2 ring, and then start to bypass oil. Virtually a no-win situation.
They must have leaned those engines out to compensate for the inclusion of burning so much oil per 1000.for emissions.

Let us know when you have one apart, with the tolerances on the piston ring and groove, compared to one with a std ring set-up.

I would have thought with this arrangement, would have induced additional liner and ring wear on the compression stroke, especially on the higher HP models, also a loss of bhp output??

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Post by AlanS »

It seems that these engines had one strange quirk with them and that was that whilst they "used" oil, they never smoked and many were passing emission tests without any problems.
A guy in Germany, a Cit mechanic reckons he has a client with a Xantia 1.8 engine which is basically the same engine, and he's been going beserk back from when it was new trying to sort out the oil useage, but every year it flies through that part of the MOT test.
As far as wear in the bore goes, this car was showing wear on one side of the bore which I honed out.
Measurements were taken at the time which showed it was within acceptable limits, but don't ask me now what they were. I was a bit surprised to see bore wear at 145K klms as normally the hone marks are still visible at this stage.
My theory was that whereas leaky stem seals would send oil down the guides with a bit of a rush and rings would force oil into the combustion chamber and hence create smoke, this was left as a light film on the walls and across the valve faces etc and would mix with the fuel vapour and burn as a constant % of each mix on each firing stroke and as a result never showed as a fuming type of spasmodic event.
It had a dose of brake fluid dropped down the plug holes a couple of years back as a dodgy way of freeing what we suspected at the time was sticky rings and gained around 10% power after that.
The strange looking greasy substance around the ports was the thing the head guy commented on as it was obviously from a long term cause and this is why I tend to think the theory of the oil vapour mixing with the fuel/air mix is a reasonable hypothesis.


Alan S
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Post by mat_fenwick »

AlanS wrote:The thing that is weird is that it always seems that the problem is more prone on low mileage models than high mile cars.
Perhaps the higher mileage cars are more likely to have been fixed - after all if you are putting in a litre every week you are going to be more inclined to solve the underlying problem. But then if the problem WAS rectified, you would have expected your explanation to have come to light sooner, unless no-one ever noticed during strip downs and simply re-assembled correctly.

The fact that it does not seem to be confined to one geographical location (in my mind) does not rule out the idea of a 'rogue' employee, or shift as engines may have been shipped from any plant to any location depending on demand.

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Post by AlanS »

Whilst I've been following this through on a few forums (mainly to settle my own and a few others curiosities) it has been confirmed that Peugeot 205s were also smitten by the same problem (as I had heard previously) but in the case of Peugeot it seems that if you complained loud and long enough, they would rectify it under warranty. The story the owners were gives was that they had received a batch of "faulty pistons" which sounds like a nice way of putting a spin on "we stuffed up in the assembly" and this way, the blame can be laid at someone elses doorstep.
Citroen seemed to be more inclined to sell the story that it was Citroens policy that cars needed some upper cylinder lube and that this was an experimental way of achieving this.
Others were told they had fitted a new type of ring and if the problem persisted, they supposedly "fitted the newer type) which looks like all they did was fit the same rings but in the correct order and pointing the right way up.:roll:

Alan S
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