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Badminton355

Kelvin J2 - Water from No2 cylinder spark plug

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Good day all,

 

I was hoping someone may be able to shed some light on my problems.

 

The boat is currently moored on the south side of the Harecastle tunnel with a poorly engine.

 

Arrived at the tunnel on Sunday, had a 30 min wait so i dropped the revs and the engine stopped. Had been going for a round 2 hours with no sign of problems. I managed to get the engine going on petrol, tried to turn over to diesel, the engine stopped, there was a louder than normal clunk when operating the changeover leaver after winding in the injector valve. Tried and tried to restart to no avail, removed the plugs to clean and noticed water on No 2 cylinder plug. Removed both plugs and spun the engine. Water was spurting out of the plug hole, the header / over flow tank water supply was spurting ever time i tried to start the engine. I rang the guru of Kelvin engines, Dick Gobel. He was unsure of what the problem was, he will be coming to have a look once I get it back to the marina at Heritage.

 

Has anyone got any ideas as to what the issue could be. I suspect cracked cylinder head.

 

I have managed to arrange a tow from a chap called Chris who is on a boat called Atomizer for Sunday the 9th.

 

Any help greatly appreciated.

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I agree with your diagnosis.  A vertical fountain from the plug hole is typical behaviour after a head has cracked.  The only other source of water would be a crack into the cylinder water jacket.  A crack like that would have to go through the liner and the cylinder itself so is unlikely.  The heads commonly go between the valves after the cooling water has dissolved away enough iron.

 

If you don't have a replacement head it  may be possible to get the head repaired.  Talk to cast iron welding services  in coalville. 01530 811308. Usual disclaimer.

 

N

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Thanks for the reply BEngo. 

Dick thinks there are a couple of Chinese copy heads available but says they are not very good and he doesn’t like them. 

 

Have you any idea what may have caused the head to crack if in fact it has. 

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Assuming that there is a crack between the valves, and I have not seen one anywhere else,  the heads crack because the space between the valves is the hardest worked part of the head and there is not a lot of supporting metal when the head is new.  This, in turn,  is because the valves (exhaust mainly) are usually  the hottest part of an  engine, and the heat from the valves has to be conducted into the head through the valve guides and the valve seats.  These then need as much cooling as possible so there has to be a water passage round the valve seats and between them.  In the model J this weakens the part of the head which has to take all the combustion pressure.  The cylinders are designed for at least  1000 psi, and were available certified as tested to that,  so the head has to be able to stand the same pressure.    All is fine when new-there is enough metal and enough water space for it all to work.  Once the cooling  water is in there, particularly sea water,  it slowly dissolves the iron out of the cast iron  head, leaving just the carbon part of the cast iron.  The remaining iron  eventually has insufficient strength to support the firing loads and a crack  results.  The preventive  is to ensure there is plenty of corrosion inhibitor in the cooling water and to top it up regularly using central heating corrosion inhibitor suitable for cast iron.  You can test for effectiveness by putting a few ordinary iron nails in a sample of the cooling water in a jam jar.  If they go rusty after a few days the inhibitor is getting tired an needs a top up.

 

You are perhaps fortunate in needing a petrol start head.  They are much more common than the cold-starting heads.   I had some new heads from Agra Engineering (in  India)  about 2001.  They were exact copies of one of the batch of  heads from the factory with the petrol combustion chamber depression on the top of the head offset to one side, leaving a very narrow land for the bolted on portion to seal to.  They worked quite happily though.  I have no idea what Agra's minimum production run might now be but it will be at more than 20 items.

 

There are other suppliers' heads about, mainly from India,  but I have not examined them so could not say what problems they might have.  The general problem with Indian engine  items is that Quality Control is unreliable and finishing standards are low.

 

I am not aware of there being a pattern for a head in UK,  nor of a  finished part drawing  which would be needed for the machining up once the base castings have been made.       Dick was at one time looking out for a pattern maker with some time on his hands and who might make us a pattern.    Once we have a pattern maker I would happily produce a machining drawing.  There are  now several foundries catering to the 'heritage' market,  mainly for road or rail steam engine parts so getting a pattern turned into machinable castings should not be a problem, but will not be cheap either!

 

The general view has always been that they are not repairable either, but modern techniques might challenge that and I am not aware that any of the specialist cast iron welders has been asked to give an opinion.  Any repair will not only need to weld up the crack, but also put back some supporting metal.   It will certainly involve machining the mended head to  renew the valve seats, and inserts might be needed.

 

Ask Dick if he still has the cracked head I cut in half for him.  If you look at that you can see the extent of the design problem and the extent to which the iron has been dissolved out by seawater leaving only a black substance which has no strength.

 

N

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36 minutes ago, BEngo said:

 Once the cooling  water is in there, particularly sea water,  it slowly dissolves the iron out of the cast iron  head, leaving just the carbon part of the cast iron.  The remaining iron  eventually has insufficient strength to support the firing loads and a crack  results. 

OFF-TOPIC

 

this can have terrible effects on cast iron parts. Unpleasant but bearable is the habit of sea water soaked parts to continue to rust under paint. At the other end of the scale are cast iron parts that you can almost pull apart with your hands

 

As you say, modern cast iron welding is pretty sophisticated, including cutting out and welding in whole new sections of castings, so it's probably worth checking out. It won't be cheap, it could be the only solution for some parts

 

Richard

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1 hour ago, RLWP said:

OFF-TOPIC

 

this can have terrible effects on cast iron parts. Unpleasant but bearable is the habit of sea water soaked parts to continue to rust under paint. At the other end of the scale are cast iron parts that you can almost pull apart with your hands 

 

As you say, modern cast iron welding is pretty sophisticated, including cutting out and welding in whole new sections of castings, so it's probably worth checking out. It won't be cheap, it could be the only solution for some parts

 

Richard

The problem of continued rusting of sea-water soaked cast-iron parts can be mitigated by removing all the paint and then soaking the part in fresh water.  It isn't a quick process though.   A thick part may take a long time- months or even years to get all the salt out.    Changing the water frequently helps,  as does agitating it. 

 

N

  

 

 

 

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Thanks for the replies guy's.

 

So I need to find new heads, Dick did mention of 2 that may be available at around £1000 each (Indian ones).

 

It is interesting to read out the water passages etc. Not long ago the other head developed a leak from the stud which holds an inspection plate on the head. The upshot was that the hole wear the stud screwed in had rusted away, the stud itself had corroded away to a fine point inside the head. I managed to get another bit of stud and install it from the back with a bolt on the back the stud to clamp it, there was just enough metal left hold the bit of stud in. Sealed up the plate and used rubber washers on the outside with a metal washer and nut. Last weeks run was a shake down to see if the fix had worked then had the issue with the other head. The 2 heads are different on mine, one has the inspection plates the other does not.

I think I need to see what the level if any inhibitors are in the water, I suspect none.

 

BEngo, I will be speaking with Dick when he returns from Scotland later in the month, I will have the boat back to the marina then. He is going to come to the boat and have a look.

Out of curiosity I bought an endoscope to have a look inside the engine, not sure if this will show anything but will be interesting to see inside.

 

The other issue will be if I can get new heads or get them replaced is to have someone do the work for me. I don't think Dick will be fit enough to do it now. I saw him in Easter and mentioned that he would not look forward to start working on engines again. Do any of you guys know of anyone who is willing to look at doing the job?

 

Thanks again guys.

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A grand for an Indian made head seems a bit excessive.   However, if you have no choices......

 

I'm afraid it is too far North for me to know who to suggest.  Tim Leech might have been a starting point, but he is sadly no longer with us.

 

If Dick isn't able to do the job himself,  (and I had heard he was cutting back hard),   I would ask if there is anyone he knows or maybe even ask him to supervise you doing the work.    A reasonably comfy chair in the corner of the engine ole, a brew now and then and perhaps some Old Pulteney at the end should not tax him too much.  Doing the job yourself  will give you a much better knowledge of your engine, if you have the time.

 

If Dick cannot be involved, a head change  is not that difficult and well within the capabilities of any  competent mechanic.  It's about a day's work.  Tools wise it needs a set of BSF Spanners- OE  and Socket up to 9/16 BSF and a big bar for the sockets plus the usual screwdrivers, scrapers etc.

 

  Mainly it consists of disconnecting everything you can see bolted to the head and then undoing the head nuts, not forgetting the small one underneath by the injector.  Then lift off head.  The injector may not want to come out of the head if it has been there for a while.  In that case take the drain valve out completely and use a small slide hammer screwed into the drain valve hole.

 

It is easier to take off the pipework etc. for both heads even if you are only going to lift one.

 

The hardest part is re-dressing the new head.  You have to swap over the venturi, the starting valve and spring, the combustion chamber, the valves and their seats and springs.  You will probably also need to transfer the special head washers too. Be careful with these -they are cast iron and snap if you are too enthusiastic with the levers etc.   Grind in the starting valve as well as the main valves, but be gentle with the starting valve.  There is not a lot of meat on the seat.  All much easier if you have a bench to work on.

 

The venturi can be a so and so to get out.  I have seen it suggested that you should drive it out with a tubular drift over the starting valve but that seems a brutal approach and bad for the starting valve.    I made a special puller.   Use the head gasket to ensure it goes back in the right orientation.

 

Refitting is then a case of putting it all back.   Use Wellseal on the head gasket.  Tighten the exhaust manifold nuts before putting the head nuts on.  Fit new copper washers to the injectors.

 

Ordinary Klingerit type gasket paper will make all the joints apart from the exhaust and I can supply new copper/asbestos substitute exhaust manifold gaskets if Dick hasn't any.

 

 

N

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Dick did some work on our J3 earlier this year. He was accompanied by a younger chap whose name I forget, the idea being that he was shadowing Dick with a view to taking on some aspects of the work himself. They share the same workshop. He seemed keen and competent in the spring, hopefully still around.

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2 hours ago, BEngo said:

Mainly it consists of disconnecting everything you can see bolted to the head and then .............................

Brilliant - info saved just in case ?

Thanks BEngo!

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All excellent info. Thanks very much for the input guys. 

First port of call is to get the boat back to the marina then see what’s what. I’ll speak to Dick and get him to come and have a look. 

 

Again thanks for all the help. 

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When you surface grind a block or head thats been raw water cooled,you can clearly see a grey zone about 1/4" wide extending from jackets into the shiny white iron.....This is a zone of chloride infiltrated iron of poor strength,and also continuing corrosion ,even when dry....

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A quick update, the heads are off. Dick Goble came along and with help from me we had them both off in about 6 hours, taking care not to damage anything. All went well. Nothing really obvious to see what maybe causing the issues. We filled the heads with water when off to see where the water may leak from, ond head showed signs of leaking from the venturie(spelling).  Dick is doing more work on them at his shop.

 

Good news is the diesel injectors were in very good condition.

 

Anyone got any spare heads???

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The most common place for a crack is in the narrow land between the two valves.  They can be hard to see so rubbing a piece of chalk over the head and filling it with paraffin can help.  Paraffin is more penetrating than water so shows up better.  

Wash any good head out with strong detergent solution afterwards though.

 

Earlier this year Tony Redshaw had a J3 which came with spare heads, cylinders and liners IIRC.  Might be worth asking after one of the removed heads if he has not sold it as a job lot.

Otherwise the Kelvin spares club (the group that bought KW's leftovers) may have an Agra one.

 

N

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Thanks BEngo. When i speak to Dick next time ill mention it to him.


Dick brought the head that you sectioned. I now have a better understanding of how the engine works.
It was enjoyable working with Dick taking the engine apart. If nothing else i can get to the areas that need cleaning now the engine is apart.


Dicks has got feelers out for some new heads. I may have got the pricing wrong before, i don’t think they are as expensive, maybe hard to find tho. There could be a couple if Indian made ones somewhere but these will need re-machining to make them fit and work correctly.
 

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