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JP2 manufacturing date confusion


tommylad

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Here's a good one for the JP aficionados...

My JP has the following stamping on it: 127JP2ME12

So, by my understanding that makes it the 127th Lister made in the year of manufacture, a 'JP2ME' which I take to be correct as my engine is a semi-marine unit. All good so far...

However, I understand the '12' means 1950 + 12 = 1962. This is confusing, as from what I can find online, the JP2 finished production in 1952!

 

Can anyone shed any light on this for me? Maybe they continued manufacturing semi-marine JPs after '52?

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There are Lister experts on here, of whom I am not one. But I found out that Lister revised their numbering system in 1952, along the lines which you state. The JP2 seems to have been in production, as you say, from 1930 to 1952. So I suggest that yours is numbered according to an earlier system, of which I have no details.

Not sure what the E means either: Electric start?

Now an expert will come along, tell me I'm talking cockalorum, and give you the correct answer.

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Here's two useful guides (although contradictory!) Neither offer any explanation for what 'E' denotes, however, as I already know my engine to be a semi-marine (intended for a boat, but not the main propulsion engine - mine was a pump for deck washing on an IoM ferry!) I'm therefore assuming E to mean semi-marine. Mine certainly isn't (and hasn't ever had) electric start.

Lister engine dating.jpg

Dating.JPG

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1 hour ago, Athy said:

Yes, the top one is what I found.

I wonder about the logic of starting a numbering series in 1952 but taking 1950 as the base year for dates.

 

Makes the mental arithmetic easier, with the last digit of the serial number and year of build being the same.

 

 

Looking at the pre-1951 numbering, does the number 127 make your JP2 (or 18/2) an early 1931 build?

buildnos.jpg

Edited by David Mack
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14 minutes ago, David Mack said:

 

Makes the mental arithmetic easier, with the last digit of the serial number and year of build being the same.

 

 

Looking at the pre-1951 numbering, does the number 127 make your JP2 (or 18/2) an early 1931 build?

buildnos.jpg

I don't think so, as they weren't known as 'JP's in 1931 (either 9/1 or 18/2) but my serial marking includes 'JP2' in it

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  • 2 weeks later...
On 24/08/2018 at 18:01, tommylad said:

I don't think so, as they weren't known as 'JP's in 1931 (either 9/1 or 18/2) but my serial marking includes 'JP2' in it

Nope you are correct in your original post with 1962

 

Lister stopped mass production of the JP's in 1952 but didnt stop mass production of the later JK until 1969 and did build engines to either spec in that interveining period. we have had many JP spec engines come through that have been build after the 1952 date. 

 

The M denotes a marine engine, the E denotes its an Auxiliary spec.

  • Greenie 1
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Anyone have ideas on how to date at JP2M when the plate is missing....and the flywheel is from a JP3? 

 

There is a plate on the reversing box but it’s tricky to read properly. There’s also some casting numbers inside the block but I don’t know if these relate to dates. 

 

Any thoughts? 

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2 hours ago, Athy said:

Excellent info Martyn, mystery solved!

What would be different about an "auxiliary spec"?

That is a how long is a piece of string question. As a generalisation the ME means it has all the marine gubbins like water cooled exhaust, manifolds etc but does not have a marine type gearbox. however from there they vary alot depending on what the engine was originally for. we have had some with flywheels at either end unlike a marine propulsion which has it at the injector pump end, we have also have them built for gensets (fixed speed governor) and for driving pumps all of which have variations in the ancillaries fitted.

2 hours ago, frangar said:

Anyone have ideas on how to date at JP2M when the plate is missing....and the flywheel is from a JP3? 

 

There is a plate on the reversing box but it’s tricky to read properly. There’s also some casting numbers inside the block but I don’t know if these relate to dates. 

 

Any thoughts? 

 

You will struggle to do it accurately in that case as those places are the only places where the actual engine number is stamped. however if it is a pukka marine engine (read as has a marine crank) then if it was a sea going commercial engine when new then the cranks are stamped with the test date if lloyds inspected. and you can also date the injection pump from the full serial number so if these match in year ish then its either a coincidence of the engine would have been build around that time.

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18 minutes ago, martyn 1 said:

That is a how long is a piece of string question. As a generalisation the ME means it has all the marine gubbins like water cooled exhaust, manifolds etc but does not have a marine type gearbox. however from there they vary alot depending on what the engine was originally for. we have had some with flywheels at either end unlike a marine propulsion which has it at the injector pump end, we have also have them built for gensets (fixed speed governor) and for driving pumps all of which have variations in the ancillaries fitted.

 

You will struggle to do it accurately in that case as those places are the only places where the actual engine number is stamped. however if it is a pukka marine engine (read as has a marine crank) then if it was a sea going commercial engine when new then the cranks are stamped with the test date if lloyds inspected. and you can also date the injection pump from the full serial number so if these match in year ish then its either a coincidence of the engine would have been build around that time.

Well I’ve also had a recon pump fitted so that won’t help. By a marine crank do you mean has a 3G box and the flywheel on the injector pump end? Where should I look for the number? 

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Arhh, well in that case your pretty much b!"£$%ed then ;0)

 

By crank I mean one destined for commercial marine use when new. so could be any type but will only have been Lloyds stamped if used in commercial marine from new. As the stamping was done by hand the location varies but is normally stamped on the side of one of the crank webs, however I have seen one with it stamped on one end of a web so only visible with the crank removed.......

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  • 1 month later...
On 03/09/2018 at 14:09, martyn 1 said:

Nope you are correct in your original post with 1962

 

Lister stopped mass production of the JP's in 1952 but didnt stop mass production of the later JK until 1969 and did build engines to either spec in that interveining period. we have had many JP spec engines come through that have been build after the 1952 date. 

 

The M denotes a marine engine, the E denotes its an Auxiliary spec.

 

Many thanks Martyn - very interesting to clear that up!

My Dad bought my engine in the early 80s and was told that it was an auxiliary engine in an IoM ferry (which I therefore assume was its original installation). It was supplied with the copper oil tank and has water cooled exhaust (manifold and silencer) and has the flywheel at the non-pump end. It didn't have the marine gearbox, so it's now running a PRM gearbox.

It's very strange to now know that it's been installed in our canal boat for longer than it was in the ferry for!

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  • 1 year later...
On 03/09/2018 at 17:51, frangar said:

Anyone have ideas on how to date at JP2M when the plate is missing....and the flywheel is from a JP3? 

 

There is a plate on the reversing box but it’s tricky to read properly. There’s also some casting numbers inside the block but I don’t know if these relate to dates. 

 

Any thoughts? 

Hi Frangar,

 

I was taking my flywheel off the other day (like you do) and noticed a stamp in my crankcase that I've never spotted before - it reads 'RUNNING TEST 19 6 62' - which I guess is the engine equivalent of a date of birth! I was very chuffed to find it, and means the stamps on the crankcase door, flywheel and now crankcase all match which 20191108_150003.jpg.b097976b32d6595da2068503509192d0.jpgis nice.

Worth checking on yours if you're still looking for something?

20191108_152200.jpg

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