Seized JP2

[Tunneltug]

I have a friend who's JP2 seized on a recent short trip. On inspection an oil union had failed and the oil lost into the bilge so its fair to assume the seizure is oil starvation caused.

 

I have not done a great deal of work on small engines like this but will try to help my friend out over the next week or so to see if we can get his boat to the Braunston show.

 

Does anybody have any experience of a seized lister JP2. My experience on larger engines was that the big end bearings were the most likely culprits but I have no idea on this model can anybody with actual experience help please.

 

Thanks

[monkeyhanger]

I have a friend who's JP2 seized on a recent short trip. On inspection an oil union had failed and the oil lost into the bilge so its fair to assume the seizure is oil starvation caused.

 

I have not done a great deal of work on small engines like this but will try to help my friend out over the next week or so to see if we can get his boat to the Braunston show.

 

Does anybody have any experience of a seized lister JP2. My experience on larger engines was that the big end bearings were the most likely culprits but I have no idea on this model can anybody with actual experience help please.

 

Thanks

My JP2 is at Braunston awaiting work from Johnno at Union Canal Carriers. He was highly recommended to me, so if you can get the boat to Braunston, he's the man to speak to!

[frangar]

I too would suggest main bearings....but if it seized suddenly that's a massive load on the crank from the flywheel.....

 

Steamraiser or Martyn from marine power services would probably be more able to give you a better idea of what would be needed...sounds expensive though!

 

It would be handy if you could keep us posted with findings as any shared JP knowledge is helpful!

 

Just out of interest what Union failed and was it a dry or wet sump?

 

I really must check my oil pressure etc more often when I'm cruising!!

 

Cheers

 

Gareth

[Mrs Tawny Owl]

Is the boat moored where Hasty is?

If so Richard and I are coming up at the weekend so he could have a quick look and do some initial diagnostics.

Drop us a PM if that's helps and we'lol arrange a time.

Sue.

[martyn 1]

Obviously its virtually impossible to say what will be damaged without a lot of diagnosis, if your really lucky it will have only done damage that can be fixed in situ.

 

But as a starter unless the owners engine room has about 4ft to spare in front of the engine, the engine will have to come out to diagnose it properly. The oil is fed to the crank via the injector pump end main bearing so if it has been run with no oil pressure to the point of seizing all the bearings will need inspecting including mains which will require the removal of the crank. As long as it hasnt damaged the crank (broke it which they have a tendancy to do) then all is not lost. But unfortunately even if you find for example one torn up big end, the engine will need pretty much fully stripping down to get any debris out of the oil ways as some of them you can't clean out without removal of the end housing, camshaft and crankshaft.

[Tunneltug]

Thanks all for your help and suggestions, Getting the engine out would be the only way of getting the crank out to change the mains.I haven't actually examined the engine yet but am going by what the owner told me. It all sounds a bit serious really and perhaps she isn't going to Braunston this year.

 

I've just got back from a long break in France but hope to get in the engine room tomorrow to have a sniff around.

 

Incidentally, soon after Hasty's launch all the bearings were new and perhaps a little under shimmed and when we were coming through bridge 13 on the Coventry the engine squeaked a bit then seized solid. I slackened the big ends off a little,squirted a bit of oil in and off we went. I checked them out later and there was no damage and so shimmed them properly but I guess this is the advantage of gun metal bearings over babbitt. Not much chance of this being the case on Egypt I guess.

[steamraiser2]

As Martyn said the cranks on Lister JPs are prone to break. This is because they are very angular and have lots of places where stress fractures can start. What is an absolute fact is that crank failures tend to occur on JPs with worn bearings. Whatever you do please don't try and run the engine on with shot bearings. A regrind and re-metalling is bad enough, the cost of replacing a cracked or broken crank doesn't bear thinking about.

Geoff

[frangar]

As Martyn said the cranks on Lister JPs are prone to break. This is because they are very angular and have lots of places where stress fractures can start. What is an absolute fact is that crank failures tend to occur on JPs with worn bearings. Whatever you do please don't try and run the engine on with shot bearings. A regrind and re-metalling is bad enough, the cost of replacing a cracked or broken crank doesn't bear thinking about.

Geoff

As a quick aside...and mainly cos I worry about such things....

 

I take it as long as you have reasonable oil pressure (20psi when running...18psi on hot idle - SAE20 oil) and no nasty rumbles then you should you be ok? I had the crank ground and new bearings fitted about 3500 hours ago and when the Pistons were pulled to sort a liner issue about 1800 hours ago the big ends were all deemed fine....mines a marine unit if that makes a difference due to flywheel placement etc.....if it was to go twang can a stationary engine crank be used on a marine unit?

 

Cheers

 

Gareth

Edited June 14, 2015 by frangar

[steamraiser2]

In car terms your engine has done around 85000 miles which isn't high but is a significant amount. As a rule of thumb it is 65% worn I would guess. Your oil pressure is absolutely fine so I can't imagine you need to worry about it too much just yet. Keep an eye on it though over the coming years and get it looked at when you notice the oil pressure is dropping off. Don't get it overhauled when the at idle oil pressure is at,all but, zero get it fixed when it is regularly between five and ten.

 

The JP (M) cranks are entirely different to the the stationary engine variant and are very hard to find these days. Generally you will have to break an engine to get a JP2M crank. We have developed a conversion crank for the JP2/3M engines but it isn't straight forward and cannot be adapted to take a Blackstone box.

 

So....Look after the crank you have!

 

Geoff

Edited June 14, 2015 by steamraiser2

[frangar]

Many thanks for that. Puts my mind at rest a bit. I always run in low compression too as I hopes this lowers the strain a bit. I will indeed keep an eye on the oil pressure. I also make sure I change the oil every year although this might change till spring after reading your comments on the oil change thread! I always clean the sump & tank when I change the oil too.

 

When stopping the engine I always lift the decompressors just before it stops to save it rocking and stressing stuff.

 

Many thanks for the advice...I know where it's going when it needs a rebuild!

 

Cheers

 

Gareth

[Tunneltug]

Just un-seized Egypt's engine. Luckily there doesn't seem to have been any obvious damage and the big end that had locked up freed as soon as I slackened the bolts on one side. I've pumped it with oil and put it back together, on hand cranking 20psi was soon achieved on the pressure gauge although it started at 5psi.

 

The oil was lost through a union up to the oil injector one of the two pipes coming up from the beneath the flywheel was leaking. This wasn't obvious as the oil ran down the pipe and sneakily dripped into the bilge some distance away. The soldered joint at tail had at some time in the distant past had failed and one of the previous owners had bodged it up with sealant which had hardened and failed.Once this is Properly reinstated we'll fire her up and see what happens.

 

I know this isn't ideal but this engine which is tired from previous negligence and neglect and is in need of a lot of TLC won't be coming out in the near future to be rebuilt. For now its field repairs only but we will get her in good working condition over the next couple of seasons.

 

Thanks to everybody for their help and suggestions.

 

Regards - Keith

[RLWP]

Did you check the shells in the seized bearing, Keith?

 

Richard

[martyn 1]

To repeat what Richard has posted in his last above. You did fully remove the bearing in question and inspect it. Didn't you!!!

 

If not please do so before starting it back up as if its damaged you wont be getting it in good working condition over the next few seasons as you will be looking for a new crank long before that if the bearing starts to fall to bits. (I have seen many of these where the white metal has broken down on the bearing face of the bearing and by the time its noticed the bottom end and oil ways are full of white metal filings and the crank journal is completely shot. The last one had been a standard journal size crank that ended up needing a maximum undersize grind to sort it out and even then the journal still had a few marks. really the engine needed a replacement crank but one was not available at the time.

 

I would be inclined to fully remove the bearing and inspect its faces and mic the crank/bearing for clearances and if its not right fit a new bearing.

 

Martyn

[RLWP]

I would be inclined to fully remove the bearing and inspect its faces and mic the crank/bearing for clearances and if its not right fit a new bearing.

 

Martyn

 

Same here. If it has seized, it must have done so by damaging the whitemetal lining of the bearing. If you are lucky, it's galled it and made a lump, jamming the rod. If you are unlucky, it's ripped the lot off leaving a bare steel shell running on the crank journal.

 

Except I'm more cautious than Martyn. Bearings are relatively cheap, certainly cheaper than crankshafts. I'd replace the shells anyway.

 

Richard

[bizzard]

And if the crank journal proves to be ok and your putting new shells in, hoist the con rod up out of the way and turn the engine over on the starter a few times ''with the stop control on'' until oil pressure builds up to make sure oil spurts out from the journals oil hole to make sure there is no blockage which might have caused the seizure in the first place.

[RLWP]

And if the crank journal proves to be ok and your putting new shells in, hoist the con rod up out of the way and turn the engine over on the starter a few times ''with the stop control on'' until oil pressure builds up to make sure oil spurts out from the journals oil hole to make sure there is no blockage which might have caused the seizure in the first place.

 

If you should choose to do this, don't wear your best shirt

 

Richard

[martyn 1]

 

If you should choose to do this, don't wear your best shirt

 

Richard

 

In fact get someone else to stand near it while you press the starter button, then laugh loudly when they end up wearing the content of the sump

[Tunneltug]

Wise words, for the sake of a few quid I think I'll bung some new shells in. The existing one that seized isn't in an unserviceable condition, a bit of scoring on the front edge but generally not bad, I've seen worse. I'll mike-up the journals which are very good indeed and source the corresponding shells.

 

I think Egypt has been very lucky, I will also put the bodged union right before proceeding and flush the oil system.

 

Thank you all for the very helpful info and tips.

 

Just goes to show this forum is indeed a very valuable resource.

 

All the best

 

Keith

[MtB]

Keith, I hope the owner of EGYPT understands and appreciates your diligence, expertise and commitment to Doing Things Nicely.

 

 

MtB

[vulpyfox]

Hmmm This is making me want to fit an oil pressure dial as well as a light/buzzer to my TS engine.

Seems a sensible call as all I have atm is the mechanical hour counter ^.^

[Tunneltug]

Keith, I hope the owner of EGYPT understands and appreciates your diligence, expertise and commitment to Doing Things Nicely.

 

 

MtB

Mike, I know Alan appreciates it and I know once the historical neglect of Egypt has been reversed he will look after her which is the most satisfying thing

[larkshall]

If you should choose to do this, don't wear your best shirt

 

Richard

Ain't dat de truth if you do just scrap shirt and use to start clearing mess

[Tunneltug]

Can anybody recommend a supplier of big end shells and perhaps shims for a JP2? I miked the journals up and they came to 2.975" diameter which I am assuming started out at 3.00"and have had a 10 thou grind. There are a few on eBay and other sites but if there is a particularly recommended supplier I'd be grateful for details.

 

Thanks again

 

Keith

[flatplane8]

Try marine power services or stationary engine parts. Google will throw up a few others too I'm sure, but I've used both those in the past.

[RLWP]

PM sent

 

Richard

 

MORE: what are the numbers on the back of the shells?

Edited June 23, 2015 by RLWP