JCB 3.8 BMC

[Dar Kuma]

since I've found out today my engine is dead, I don't fancy chucking money at it so will this one do for my narrowboat.

 

http://www.ebay.co.uk/itm/JCB-3-8-4-CYLINDER-BMC-DIESEL-ENGINE-RUNNER-/251364053736?pt=UK_CarsParts_Vehicles_CommercialVehicleParts_SM&hash=item3a867712e8

 

thanks in advance.

[ditchcrawler]

Don't forget you will need to marinise it, if you can get the bits.

[Bee]

I`ve seen them fitted in at least 2 narrowboats, nothing especially wrong with them but they are a bit old, hefty and probably thirsty, really 3.8 is about twice the size you need. What is your dead engine? unless its got a hole in the crankcase and a cracked head it is probably ok to recondition and the gearbox, bellhousing, engine bearers, wiring, pipes, hoses, fuel lines etc. etc. will just fit straight back on again.

Edited November 29, 2013 by Bee

[Dar Kuma]

Bee, it would be too expensive to recon and I don't have that sort of money so I'm looking at alternatives.

 

my engine, as far as I'm aware is a dead mitsubishi thorneycroft 4 cyl, the pistons are seized and probably rusted and no, I didn't do it.

 

Dcrawler, yeah i realise that how much would that cost, still probably a better price than getting my old engine recond..

 

twice the power twice the speed....

Edited November 29, 2013 by Dar Kuma

[alan_fincher]

It is ridiculously large for a narrow boat.

 

Just completely over the top.

 

If cash is tight, you are surely better looking for an engine that is already marinised?

 

Taking on something like this, and then trying to buy the marinisation parts will surely be no cheap option.

 

Then, if you manage it, you have a boat with a far too big engine.......

[ditchcrawler]

How about this http://engines.apolloduck.co.uk/feature.phtml?id=335864

http://engines.apolloduck.co.uk/display.phtml?aid=334838

http://engines.apolloduck.co.uk/display.phtml?aid=334713

And so the list goes on at http://engines.apolloduck.co.uk/listings.phtml?next=0&sort=0&fx=GBP&limit=10&cid=262

[Dar Kuma]

thanks ditchcrawler, i forgot about apolloduck

[Arthur Brown]

If you are really certain that the pistons are seized then look at finding another short engine of the same type, then all the marinising bits should fit. Fitting a replacement engine of a different type can mean replacing the engine bearers even if the prop shaft will line up.

 

That Ebay engine is too big for a narrow boat and already has a warning that the injector pump is suspect

Edited November 29, 2013 by Arthur Brown

[Beaker]

It is ridiculously large for a narrow boat.

 

Just completely over the top.

 

That was my first thought, our engine's less than half that capacity and is more than adequate.

Edited November 29, 2013 by Beaker

[Theo]

 

That was my first thought, our engine's less than half that capacity and is more than adequate.

Having an overlarge engine must be a real pain. If it is propped for its power it will push the boat along far too fast even on tickover. You will always be taking it in and out of gear to keep your speed down.

 

N

[cereal tiller]

It is ridiculously large for a narrow boat.

 

Just completely over the top.

 

If cash is tight, you are surely better looking for an engine that is already marinised?

 

Taking on something like this, and then trying to buy the marinisation parts will surely be no cheap option.

 

Then, if you manage it, you have a boat with a far too big engine.......

 

On the subject of engine size,am i right in thinking that a Lister JP2 is nearly 3 litres cubic capacity and a JP3 is nearly 4 litres?

 

Both these engines are often used in narrow boats?

[Mike Tee]

JP2 - 2868cc

JP3 - 4312cc

[BD3Bill]

 

On the subject of engine size,am i right in thinking that a Lister JP2 is nearly 3 litres cubic capacity and a JP3 is nearly 4 litres?

 

Both these engines are often used in narrow boats?

BD3 Beta / Lister CRK3 is 3.14 litres BUT they are derated and modified with different fuelling and oil pumps, to run at a lower tickover.

I.e. the OP would need to do this to the JCB engine in question as well as the marinisation parts OR fit a 3:1 reduction gearbox ??? Plus the OP will need to fit a large prop to convey all that torque, which means possibly modificaions to the stern gear/skeg/rudder…..

Oooh it all adds up dunnit?

[cereal tiller]

JP2 - 2868cc

JP3 - 4312cc

So why would a BMC3.8 be considered to large for a narrowboat?

[ditchcrawler]

So why would a BMC3.8 be considered to large for a narrowboat?

Probably the BMC 3.8 wont run at below 800rpm. I cruise at 800 rpm.

[Geoff Taylor]

Hi, I know this engine pretty well and this particular unit is a very early unit (JCB 3C mk 1 or 2 or Nuffield tractor) the later models had a CAV DPA injector pump as opposed to the Simms inline. I wont dispute its suitability for the job but wish to point out that the JCB engine has no normal flywheel bell housing as such and would be a devil to adapt. Much better and cheaper to strip and assess the damage to your original engine I would think before jumping to an alternative.

[RLWP]

So why would a BMC3.8 be considered to large for a narrowboat?

 

They're all too large for a narrowboat.

 

You only fit a JP2 or JP3 for the sake of the engine itself - not for it's appropriateness

 

The BMC 3.8 is too big, and doesn't have any historic or aesthetic appeal

 

Richard

[BD3Bill]

Probably the BMC 3.8 wont run at below 800rpm. I cruise at 800 rpm.

Agreed Brian, the OP will get shouted at if they hook the JCB up to a 22" x 22" and end up up doing 6

knots at a tickover!

[cereal tiller]

Agreed Brian, the OP will get shouted at if they hook the JCB up to a 22" x 22" and end up up doing 6

knots at a tickover!

IIRC the 3.8 BMC has an idle speed of 550 rpm

 

As does the 1.5 and 2.5,cant remember numbers for the 1.8

 

My 70 foot narrow boat has a BMC 2.5 with a 3 to one reduction and tick ,over hardly moves the boat,canal speed is 3 MPH at 950 rpm

 

Thames speed is 5 MPH at 1500

 

Getting "shouted at" speed on the Thames is 2000

[ditchcrawler]

IIRC the 3.8 BMC has an idle speed of 550 rpm

 

I did say probably

[by'eck]

JP2 - 2868cc

JP3 - 4312cc

 

 

So why would a BMC3.8 be considered to large for a narrowboat?

 

You can't compare an old JP with that of a later designed higher revving engine developing over 50hp. The JP2 @ 1000 rpm only develops around 18hp which puts it the same ball park as Russell Newberry/National DM2's fitted to working boats. Even the JP3 only develops 27hp.

[Dar Kuma]

thanks for the replys, so the jcb engine will not be suitable unless major modifications.

 

I have now found a suitable engine.

[The Commodore]

Bit late on this but I have the BMC 3.8 Commodore and it is very easy on juice and also has the power to cope with fast flowing rivers during flood conditions that i find myself in often, not sure how the 1.5 would cope with same and wouldn't wish to chance it, having recently rebuilt it completely i have great respect for it and consider it bullet proof.

[rrt2]

 

On the subject of engine size,am i right in thinking that a Lister JP2 is nearly 3 litres cubic capacity and a JP3 is nearly 4 litres?

 

Both these engines are often used in narrow boats?

Its not just the cubic capacity ( cc ) its the brake horse power and torque that is the difference. A JP2/3 does not produce a lot of horse power.

In reality its a very low power output engine. From memory a JP2 is 18 bhp and a JP3 is 27bhp