Exhausted!

[1577Participant]

Hi
A real problem with our 55 lt15 which emits vast quantities of steam from the exhaust.
First thoughts are obviously the head gasket but I have just completed the third replacement using the Club copper gasket to no avail. Before the last attempt, I had the head pressure tested to 4 bar and alignment checked.When dismantled,it seems that water is getting into no4 cylinder and to a lesser extent no3. There was some corrosion on the threads of the spark plugs to these two cylinders. As far as I could see, the liners in the 11D block look fine but I didnt want to turn it over for a thorough check for fear of uprooting them.
The odd thing is that the problem is intermittent, hot or cold, it will suddenly start or stop and the quantities of steam can be quite spectacular.There is no sign of water in oil or vice versa.
The car goes like the clappers with no performance loss and the situation is a mystery.
I can only think there must be a problem wirh the liners not sealing somehow and I should be very interested to know if others have experienced similar problems.Regards,
Michael Bromley.

[David FaulknerParticipant]

As far as I could see, the liners in the 11D block look fine but I didnt want to turn it over for a thorough check for fear of uprooting them.

Use some bolts and washers to hold the liners down while you turn the engine over aka:

How much water disappears from the radiator when the car is ‘steaming’

[ChrisParticipant]

some thoughts – you probably know all this but here goes anyway…

Steam must be from water. It’s either coming from the coolant or from some other water source – see below.
If the water is coming from the coolant it’s either the head gasket, the bottom liner seal or a crack somewhere.
If it is intermittent I would think it is least likely to be the head gasket – and more likely to be a crack in the metal.
The only thing I know about the bottom liner seal is that they don’t like being disturbed – hence Dave’s recommendation. Do they fail otherwise? – I haven’t heard of it but that doesn’t mean much.

So – I would think about there being a crack somewhere – which I guess would most likely be a liner – would a crack in the head result in water getting into the combustion chamber? This would need something like a UV dye penetrant test. See – https://en.wikipedia.org/wiki/Fluorescent_penetrant_inspection. But you’ve had the head pressure tested so that sounds unlikely. So that leaves the liners.
There’s a kit you can get to test the coolant for CO2 content – based on the premise that, if coolant can get into the combustion chamber, then combustion gas by-products can get into the coolant. Given that the cooling system is not pressurised I would think this is a fair assumption. Here’s an example of such a kit – others are available.
http://media.wuerth.com/stmedia/shop/masterpages0000/std.lang.all/07234.pdf

Where else can the water be coming from? A silencer full of water might give a similar effect. You would only get steam when the exhaust is hot enough to start boiling it off quickly. Then you see the cloud of steam and you slow down and the exhaust cools off again. Why would a silencer become full of water? Condensation / rain? Don’t know really but it might be worth checking this is not the case before ripping things apart too much.
In a previous life I did some emissions work on diesel engine development – there was a problem with the vehicle’s exhaust giving off a cloud of steam after sitting idling for a while and then accelerating. This was because the engine produces water as a by-product of combustion and that water was condensing in the cool exhaust and forming a puddle somewhere. Then, when roaring away from the lights it would be boiled off. It was worse on cold days.
In which case your corroded spark plug threads could be a red herring. Or not.

Chris

[1577Participant]

Many thanks for the responses.
A very clever hint on retaining the liners..never thought of that one! The car has always had a liking for losing water but we shall see in the next couple of weeks on a planned trip with our French club pals.
I wasn’t aware that you could obtain a kit for testing for combustion gases in the coolant and that seems a really useful check. I see Amazon do a kit for about 30 pounds and I shall order one. I’m pretty sure that the vapour is not due to water in the exhaust system as it can happen any time even after a long drive.
The liners remain the main suspect but again,as the moisture softens the carbon in two cylinders,this may not be the case. The other possibility is a warped block, heaven forbid!
Many thanks again and I shall update in the future.
ps We were thrilled to see our car in the photos on the club site. It’s the French reg one in the field taken at the tour De Dordogne in 2015 which we helped organise. The car was fine then!

[ChrisParticipant]

Hi Michael – This one from Amazon?

 

Actually this is as much about testing I can insert a picture.

I hope you get this leak sorted.

Chris

[1577Participant]

Hi Chris,

Thanks for the info. I haven’t gone down this road as yet but gave the car a good run yesterday on a ‘ballade’ with our local club. Lots of head scratching with fellow members particularly with the guy who was following us in the cloud of steam.

After eliminating the cylinder head from the list of suspects, I am now convinced it’s the bottom half which is the problem and have now discovered that there is enormous back pressure being generated in the crankcase and evident in the rocker cover. The latter is in fact connected to an oil bath filter by a non standard hose breather connection. So, it looks like a failed piston or liner or both is the root of the problem and I shall have to strip it right down to find out. I am not familiar with wet liner engines and I shall have to see what info I can find on liner replacement, particularly how the seal at the base is dealt with. I note that the club spares list includes liners and pistons. There may be a tech article in the club on line archive if, ahem, I can get into it.Thanks again for your kind interest.

Best Regards, Michael.

 

[David FaulknerParticipant]

I am not familiar with wet liner engines and I shall have to see what info I can find on liner replacement, particularly how the seal at the base is dealt with.

The owners manual gives all the details of how to build an engine bottom end including the heights at which the liners need to be above the block to ensure they are clamped down properly by the cylinder head but are done with basic ‘line’ diagrams, for a few real world pictures, you can see some online at http://osl282.info/page.php?18 

Ian’s long thread ‘project’ forum on site: https://traction-owners.co.uk/forums/topic/1955-traction-11b-barn-find-project/ is also a good source of information

[BernieParticipant]

I offer two contributions to your dilemma:

1) My observations – I do not believe a leaking liner seal can possibly allow coolant to get into the combustion chamber.

The seal is between the liner and the block so any coolant getting past it will go directly into the crankcase/sump.  Even if a large leak leads to a sump full of coolant/steam I cannot envisage how it might possibly by-pass the piston (from below) to get into the bore.  On top of that, there is apparently no coolant in the oil so, again, I think the liner seals must be intact.

My next thoughts are therefore that the problem is either a cracked head or blown gasket.  In my mind a third possible solution would be a split in the liner wall, between the water jacket and the swept section of the bore, but I have never ever heard of that happening.

2) If you do need to remove and refit liners – At the time the manual was written, the standard engine was the “Perfo” and the liner gaskets were a relatively thick, spectacle shaped, wire-reinforced composite construction, each of which sealed two liners.  Their thickness meant the barrels had to be significantly shorter than the height from the seats in the block to the head surface of the block.  The design changed with the introduction of the D engine when liners were taller and the thick gaskets were replaced by a much thinner shim-like paper or polymer item.  The latter are normally single cylinder gaskets but I have also seen them cut in pairs.  As long as they are correctly fitted without rupturing or overlapping, they create a very good seal.

If you still have original Perfo liners and intend to refit them you will need to obtain the correct style gaskets and follow the procedure in the manual whereas a new set of liners will normally be supplied complete with gaskets.  In the latter case, new piston/liner sets plus the gaskets will be those for a standard (un-modified) D type block.  If you obtain an “old new-stock” piston/liner set you should first determine whether they are Perfo or D.

Phil Allison and I have recently rebuilt a pair of 6-cylinder engines – the liner assembly is the same as that of the fours. The method we used was as follows:

Having cleaned the liner seats in the block the liners were fitted without any gaskets in place and the whole of the head surface of the block/liner assembly was machined flat.

The engines were then assembled with new liner gaskets of the correct thickness to give the specified stand-off.  The book states the liners should stand 0.05/0.10mm proud of the block surface so we used 0.08mm thick gaskets (obtained from Darren Brownhill of Citroen Classics) and my rebuilt 6 engine has now done about 3000 miles without (gasket) problems.  Over the years I have assembled a number of engines in this way and have never experienced any failure of either the liner gaskets or the head gasket seal at the top.

N.B. – A key factor during assembly is to align the flats on the OD of the gaskets so there is no overlapping and then ensure the liners are firmly secured until the head is fitted so they cannot be disturbed possibly damaging the gaskets.

B……………………

[1577Participant]

Many thanks to all for the suggestions and advice.

I shall remove the head again and do a more thorough check of the liners with them clamped down as Dave has illustrated. Water penetration into a cylinder via the lower gasket is, I agree, unlikely or even impossible but I did see an entry on YouTube which showed a penetration failure due to cavitation.

In an effort to see if there is a reason for the pressure in the crankcase, I treated myself to a cheap combustion pressure tester. After a warm up of the engine, I recorded between 6 and 7 bars on all so no problems there I guess. What I did notice however was wisps of vapour from the spark plug hole on no 4 cylinder. This must mean that water is somehow finding its way into this suspect cylinder and it must in all likelihood be from the seal between block and head despite the fact that the gaskets I have removed show equal and effective compression.

I shall have the geometry of the head checked again and also check the projection of the liners as detailed by Bernie. Failing this, I shall somehow have to see if the block itself is distorted.

Thanks again.

 

 

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