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A tale of two JP3s


Giant
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We are embarking on our next project, and are starting this thread to record progress, seek advice, and of course most important of all: to entertain you all with photos and stupid questions.

 

The concept is simple: take two Lister JP3Ms, both in dubious condition, and end up with a decent one installed in the boat, doing as much of the work as possible ourselves. The reality will no doubt be long and complicated.

 

Our boat is a Sheffield size Humber keel, she had a JP3M fitted when built in 1953 and the engine room is in original condition (to the extent we don't think it's really been cleaned since then...)

 

Engine #1

 

 

This is the engine currently in the boat, serial number 473JPMP7, built 1957 (so must have replaced the original engine at some stage). We had a long thread on here about this engine when we first bought the boat and were preparing her for a sea passage. We rebuilt the top end including cleaning up & skimming the heads, regrinding valves & seats, injectors rebuilt by Peter Slater, renewed all gaskets, redid the fuel system, and cleaned out a great deal of rust & mud from the water passages in the block.

 

The block however has an old frost crack to the water jacket on the port side, and some hairline cracks propagating from there. It has been this way for probably 20 years, the crack is rusted up and doesn't leak, and despite some hairlines running in the direction of the crankcase there has never been any sign of leakage between water and oil. Nonetheless, we would prefer to replace this block as it's a permanent source of worry.

 

It also makes a nasty banging we've been advised is due to worn main bearings. You can hear it in the video above. It happens every second shaft revolution, so probably aligning with either the compression or power stroke of one of the cylinders but I've never really been able to identify which it lines up with.

 

In short, the top end is good but the bottom end really wants a rebuild, and either a replacement block or major welding / metal stitching work.

 

Despite all this it runs OK and we have been out on the Humber, the Blackwater and the Thames with it when we've had to move the boat.

 

Engine #2

 

post-19732-0-56034400-1486349052_thumb.jpg

 

We got lucky about 18 months ago and bought this engine (serial 15573JPM2, built 1952) from a boatyard that was closing down. They had removed it a year or so earlier from a barge that was replacing it with a newer engine. As far as we know it was in running condition when removed - it turns over and gets compression - but we know nothing beyond that about its condition or history, and it seems unlikely it would have been replaced if running OK.

 

We built a frame on an old MOD bomb trolley to take it away and have been keeping it in storage under a good tarp, visiting now and again to check on it and turn it over. Up until now we haven't been able to spend any time working on it beyond that.

 

It's missing the water manifold, but we can take that from #1 along with the rest of the top end which we already overhauled and know to be good. It's got a 3:1 reduction box rather than the 2:1 we have & need, so that 3:1 box will be up for grabs when we're done if anyone wants it. Everything else seems to be present. The flywheel has the ring gear which #1 lacks, and after some digging round the yard we even got the starter motor.

 

In short, it's a mystery engine that has some bodges on it and may well be knackered. That said, we ultimately only really need the block - which appears to be sound - anything else is a bonus.

 

The plan

 

The first step is to try and fire up #2 and see if and how it runs. In the unlikely case that it runs perfectly, we would probably just go ahead and put it in the boat after transferring some already-overhauled parts from #1. More likely, we will need to do some other work to get a good runner before doing that. Worst case, we will end up stripping down both engines and choosing the best parts from each to use in a full rebuild.

 

We are not trying to achieve perfect factory condition as offered by the likes of Martyn & Geoff - just a working engine that we can take out on the river with reasonable confidence. We'd like to do as much as we can ourselves, although obviously if it comes to things like grinding crankshafts and remaking bearings, those will be going away to the professionals. This isn't motivated by saving money, but rather that we've found we both like working on engines!

 

First steps & questions

 

We are currently putting together a plan for all the plumbing we will need to set up to run engine #2 out of the water on its trolley. Fuel and water supplies seem fairly obvious but we're less sure about a temporary solution for the oil tank. Would a simple container and an inline oil filter of the right grade suffice, if everything is placed at the right heights, or are there pitfalls to watch for here? We'd rather not remove the tank that's currently fitted to the boat with engine #1.

 

Our other main question at the moment is: given a JP3M in unknown condition, what obscure things might be wrong that could actually cause damage if we try to start/run it? Aside from basic visual checks, turning over, checking compression and changing the oil, is there anything you would investigate more carefully before trying it?

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I admire your optimism, however experience has shown (time and again) that what you'll find is the same parts worn or knackered in both engines.

 

The age old 'make one good engine out of two knackers' just leaves you with two sets of the same broken bits and two sets of serviceable ones.

 

Nevertheless, given enough time and money there's no aspect of the JP that can't be repaired or, pockets allowing, remade so...

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Good luck with the engines, should be an interesting project. I have heard that occasionally water can find its way into the injector pump and partially seize the camshaft inside, May be worth checking?

the jp3m in Hawkesbury might have started out in a humber keel. It has humber stamped into the brass cover on the rocker cover - not definitive but I can't think of any other reason for this stamp to be there.

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Wot James said.

Dont wastetime trying to run No2. If it runs you will be no wiser about the real state of the crank and bearings and if it doesn't you may well harm something.

Take the doors off and have a look in the crankcase for bits of whitemetal etc. The take a big end apart and have a look at that. Measure the crank for size and ovality. Do the rest of the big ends similarly. Then drop a lower main bearing cap and have a look at that.

 

Lever the flywheel up and down to see if there is play at the front bearing.

If all that lot are OK then (apart from having a surprise) it might be worth a tty at a start.

If there is wear etc you can now start to budget for the work needed.

 

No point in doing half a job either. The East coast as a lee shore with a dodgy engine is not my idea of a game of soldiers.

 

N

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To repeat what has been said so far and to add a little more

 

Save yourself the time of trying to get the second engine running as it will tell you little about its overall condition (JPs will run ok even when very knackered). check the end float on the crank and as previously mentioned check the crank for lift and if either show issues just strip it down for a measure up. very commonly the bearings start to fall to bits on these if left sat for long periods of time so if the history of this engine is unknown you will need to dismantle the bottom end to check it over anyway. Running it on duff bearings may well turn an engine that just needs a couple of replacement bearings to one that now needs a crank grind as well.

 

If you need the wear tolerances for the various bits let me know as many are not in the manuals and we have them on record from Lister's JP factory overhaul specs. these state the as new, max limits and the tolerance at which Lister deemed it required replacement during an overhaul. I think I posted these for the crank bearings a long while ago but cant find the thread at the moment

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To repeat what has been said so far and to add a little more

 

Save yourself the time of trying to get the second engine running as it will tell you little about its overall condition (JPs will run ok even when very knackered). check the end float on the crank and as previously mentioned check the crank for lift and if either show issues just strip it down for a measure up. very commonly the bearings start to fall to bits on these if left sat for long periods of time so if the history of this engine is unknown you will need to dismantle the bottom end to check it over anyway. Running it on duff bearings may well turn an engine that just needs a couple of replacement bearings to one that now needs a crank grind as well.

 

If you need the wear tolerances for the various bits let me know as many are not in the manuals and we have them on record from Lister's JP factory overhaul specs. these state the as new, max limits and the tolerance at which Lister deemed it required replacement during an overhaul. I think I posted these for the crank bearings a long while ago but cant find the thread at the moment

What causes the bearings to fail when an engine is laid up?

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Looking forward to seeing how you get on, they are pretty simple engines to work on and there is lots of good advice from the more experienced on here. Big end bearings seem in short supply, I had my shells re-metalled by JEL bearings @ £125 per journal.

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  • 2 weeks later...

We went over to have a quick poke around the bottom of engine #2 today, only briefly as it was towards the end of the day, but should be back soon.

 

Levering the crank back and forward with a bar and measuring the play with a DTI, we get an end float of just under 0.010". Will need to come back with more leverage to try and lift the flywheel.

 

Didn't get a big end off yet as the engine is up against a wall at the moment so didn't have good access to the bolts at the other side.

 

Interestingly though, all the big end bearings are retained by modern nylock nuts, rather than the original castellated ones.

 

It looks like this bottom end may have had some work done already.

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We went over to have a quick poke around the bottom of engine #2 today, only briefly as it was towards the end of the day, but should be back soon.

 

Levering the crank back and forward with a bar and measuring the play with a DTI, we get an end float of just under 0.010". Will need to come back with more leverage to try and lift the flywheel.

 

Didn't get a big end off yet as the engine is up against a wall at the moment so didn't have good access to the bolts at the other side.

 

Interestingly though, all the big end bearings are retained by modern nylock nuts, rather than the original castellated ones.

 

It looks like this bottom end may have had some work done already.

 

 

 

Not necessarily. When I entered the world of engineering in about 1975, Nyloc nuts were widely used IIRC.

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What causes the bearings to fail when an engine is laid up?

 

Electrolytic action between two dissimilar metals will cause the softer material, in this case the whitemetal, to erode away. It causes pits in the bearing face which fail rapidly when loaded. It seems to be a common thing with Lister and Gardner engines (and many others) that have been laying around for a while. It seems to be worse in older engines with lower quality whitemetal than is commonly used nowadays. The magnetic influence of the planet also has a hand in this and it's pretty common to round up these effects under the term "brindling"

 

The higher quality white metal in use today is far less prone to it but rest assured that even now engines can fizz away if the conditions are right.

  • Greenie 1
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Not necessarily. When I entered the world of engineering in about 1975, Nyloc nuts were widely used IIRC.

 

Sure, but this engine was built in 1952 and even our other one, a very late JP build at 1957, still has the castellated ones.

 

So what I'm thinking is that the big end bearings have probably been replaced at least once in its life. Given that the end float seems to be within spec, I wonder if the mains were done too.

 

Grebe: we certainly won't be reusing the nylocks, and I think I'd rather replace them with the original castellated nuts and locking pins from engine #1, although will need to take into account the stuff in this thread.

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Electrolytic action between two dissimilar metals will cause the softer material, in this case the whitemetal, to erode away. It causes pits in the bearing face which fail rapidly when loaded. It seems to be a common thing with Lister and Gardner engines (and many others) that have been laying around for a while. It seems to be worse in older engines with lower quality whitemetal than is commonly used nowadays. The magnetic influence of the planet also has a hand in this and it's pretty common to round up these effects under the term "brindling"

 

The higher quality white metal in use today is far less prone to it but rest assured that even now engines can fizz away if the conditions are right.

 

Can you cite evidence for much of this?

 

The Galvanic or electropotential series as per:

https://en.wikipedia.org/wiki/Galvanic_series

https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page)

 

suggests that Zinc (-0.76V) should go into solutions before iron(steel) (-0.44) which I think we all here accept, but that steel(-0.44) should go into solution before lead(-0.126V) and tin (-0.13V). Therefore I was wondering why you might think the whitemetal should corrode first?

 

It would require moisture in the oil for any electrolytic action to take place. Engines I have dismantled, even with little protection from the environment have typically retained an internal film of oil on bearing surfaces, preventing this kind of corrosion.

 

There has been a lot of assertions made on magnetic fields on corrosion, hard water and soft water, but simply nothing has even been proven. While there might be an North, South, East or West difference in orientation, it's more likely to be the effects of weather.

 

BICBW of course.

Edited by Mikexx
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Electrolytic action between two dissimilar metals will cause the softer material, in this case the whitemetal, to erode away. It causes pits in the bearing face which fail rapidly when loaded. It seems to be a common thing with Lister and Gardner engines (and many others) that have been laying around for a while. It seems to be worse in older engines with lower quality whitemetal than is commonly used nowadays. The magnetic influence of the planet also has a hand in this and it's pretty common to round up these effects under the term "brindling"

 

The higher quality white metal in use today is far less prone to it but rest assured that even now engines can fizz away if the conditions are right.

thanks, very interesting

 

 

Sure, but this engine was built in 1952 and even our other one, a very late JP build at 1957, still has the castellated ones.

 

So what I'm thinking is that the big end bearings have probably been replaced at least once in its life. Given that the end float seems to be within spec, I wonder if the mains were done too.

 

Grebe: we certainly won't be reusing the nylocks, and I think I'd rather replace them with the original castellated nuts and locking pins from engine #1, although will need to take into account the stuff in this thread.

mine is a late model and has the castellated nuts, I'm sure you're correct regarding work having been carried out

 

 

Can you cite evidence for much of this?

 

The Galvanic or electropotential series as per:

https://en.wikipedia.org/wiki/Galvanic_series

https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page)

 

suggests that Zinc (-0.76V) should go into solutions before iron(steel) (-0.44) which I think we all here accept, but that steel(-0.44) should go into solution before lead(-0.126V) and tin (-0.13V). Therefore I was wondering why you might think the whitemetal should corrode first?

 

It would require moisture in the oil for any electrolytic action to take place. Engines I have dismantled, even with little protection from the environment have typically retained an internal film of oil on bearing surfaces, preventing this kind of corrosion.

 

There has been a lot of assertions made on magnetic fields on corrosion, hard water and soft water, but simply nothing has even been proven. While there might be an North, South, East or West difference in orientation, it's more likely to be the effects of weather.

 

BICBW of course.

It is not unusual for oil in an engine to contain a small amount of water.

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It is not unusual for oil in an engine to contain a small amount of water.

 

It certainly does, but detergents are added to remove the likelihood of emulsions that do the damage.

 

If using a classic motor oil without any modern additives I would agree. New oils are very different and have all manner of corrosion inhibitors where the crankcase is bathed in water vapour.

 

While an oil might degrade over time, it degrades much slower at low temperatures than working temperatures.

 

Given that oils are designed to have an intermittent working life of at least 1 year, and are often used for a number of years without serious harm, I don't see the difference between laid up for a number years and being worked for those years in terms of corrosion.

 

Perhaps I'm biased, as I've only seen corrosion in bearings and journals where the oil has been displaced by water.

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I'd imagine some of these older engines could be laid up for decades, probably not serviced beforehand, maybe this could be the case. Not something I have experienced personally, but an interesting concept.

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Interesting thoughts on corrosion.

 

This doesn't seem to be an engine that's sat around for decades - everything suggests it was last running around 3 years ago, and then sat around outside for about 12-18 months before we bought it and put it under cover.

 

There certainly has been water in the system though, as we found quite a bit in the bottom of the sump when we scooped out a jamjar's worth to look at this weekend, and there was also an odd smell out of the crankcase when we first opened it - I'm guessing from microbial growth. An obvious route for water entry would be the port for the oil return hose, which had been sitting open exposed to the rain.

 

There was no immediate appearance of white metal fragments in that sample, but Wren is going to poke at it in the lab and see what shows up.

 

I'm concerned that we will now have spread this water around by turning the engine over, but I don't understand the oil pumping system well enough to know. I'm guessing we may want to empty the sump and try to flush out the system with new oil as soon as we can.

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I've had an engine immersed in water for a week and it survived and still running sweet. But the engine wasn't turned over. There was an amount of 'sticktion' where (after the oil change) I initially used a socket on a long bar to free up the engine. The engine was then spun with the injectors removed to empty the bores of water.

 

As you intimate, I would be concerned that water has been drawn into the oil pump.

 

I feel you have two choices, either an immediate strip-down or empty the sump as best you can, refill with oil and turn the engine over, possibly running oil down into the bores and they will have minimal lubrication. There is a chance that the oil strainer and pipework are still full of oil.

 

The fact you can turn the engine over says a lot about the condition of the bores and rings. The first thing that happens to an engine unused and kept outside is the bores and rings rust together and the mass appears to be locked solid.

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Quick question, what are the nominal diameters for the main and crank journals? I want to be sure we have micrometers with enough reach, that I trust the accuracy of.

Edit: oops, don't mind me, just found the section of the manual that lists these as 3" each.

Edited by Giant
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  • 1 month later...

Okay, time for an update on this.

DSC_7095.embedded.jpg.4a8564b6b8611aae64b0d8c0d9e790a8.jpg

We started stripping down engine #2 in earnest yesterday; have got the injectors out and fuel pump off which we will probably just send over to Peter Slater, manifolds etc off, one head off, and one big end opened up. We haven't been able to shift the rocker shafts on the other two heads yet, nor the gudgeon pin on the accessible piston. We will need to come back with superior force - suggestions welcome.

This is the state of the bearing surfaces:

DSC_7087.embedded.jpg.fde68aaf391d1b31ad0763ec8d9214fa.jpgDSC_7092.embedded.jpg.d5ad2148d40d71ac15bc0e108cf1ba77.jpgDSC_7110.embedded.jpg.968ca51a992ee70f6a71cd293d719607.jpg

The crank journal measures up at exactly 0.020" undersize. Same measurement horizontally, vertically and diagonally. I'm guessing it has been ground down to that, fitted with an 0.020" undersize shell and then seen negligible wear since. Again, it looks like we may have got very lucky with this bottom end.

What I really don't understand is: if the bearing work was done not many hours ago, why did someone go to all that effort and not give the block a good general cleanup at the same time? There is thick layer of what looks like limescale around the port connecting over to the silencer, and dense mud and rust piled so deep in the block that water doesn't flow out with the drain tap opened, even with substantial poking. Feeling around with a screwdriver it seems inches deep in there.

DSC_7105.embedded.jpg.f234d9859354f247866323e9250fa25d.jpg

Few more photos of other removed bits - intake manifold:

DSC_7103.embedded.jpg.3b4505b7e4f41c13f1bc85c2104272a9.jpg

Silencer and exhaust manifold:

DSC_7102.embedded.jpg.939acfb1e9bd97a125b9e5da286b106c.jpg

We were pleased to find this troublesome bit in far better condition than our existing one on engine #1:

DSC_7100.embedded.jpg.8cb1f1ed41856792225be7e5f79a2f29.jpg

Injectors - the one on the left is different to the other two, it has a sort of domed nut on the top that prevents the clamp plate being removed. Is this an earlier / later type?

DSC_7096.embedded.jpg.85a6f3e42ee85a5c576f04447ed82df0.jpg

State of the nozzles:

DSC_7097.embedded.jpg.76d839c8eebcafdd17cb93c879a5a1a1.jpg

The removed head:

DSC_7094.embedded.jpg.191aa80e624c7bba49b8b4fe32656fac.jpg

Fuel pump:DSC_7093.embedded.jpg.a27fcaac7fe9f5f04b09d9457e5ac913.jpg

Piston (the bottom ring broke when it slipped back and hit the cylinder rim):

DSC_7107.embedded.jpg.165c6c41a6b90791645c56bfd67a899c.jpg

DSC_7104.embedded.jpg

  • Greenie 1
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4 hours ago, flatplane8 said:

Bearing surfaces look pretty decent, if the engine was still in a working boat they are likely to have fixed it, but not worried about cosmetics. The exhaust manifold looks good too!

The manifold looks excellent, I had to ask a friend to fill the pitting on mine with weld and reface it.

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