BMC engines, good or bad? Engine inside boat, good or bad?

[Pykebird]

I love my BMC. It's the second one I have had inside my boat in the last 11 years, not because of problems, the chance for a younger, better looked after one came up, so I took it!

I have had my share of "issues recently, but having just found out that the engine itself was NOT overheating, just the gauge wasn't compatible, the engine itself was not at fault.

It seems to be an engine most people are happy to work on, and I cannot thank calcutt boats enough for their helpful attitude and great service every time I call them up.

But I do know that my engine is important so I do my best to look after her. I have moved her inside the boat which makes it much easier to work on as you can get to everything, just as well!. This does mean it is slightly more noisier but if I am not cruising I only need to run her for an hour or so, something I can live with.

[alan_fincher]

Am I the only one who is confused in this thread?

 

Is it a BMC or a BD3? Is it under a cruiser stern or in an engine room?

 

What on earth are we taliking about?

 

No it's not just you!

 

i responded about BMCs because that's what the thread seemed to be about, but once we got on to Beta marinisation of a Ford I have also lost the plot.

 

I'm staggered though to learn just how unreliable and dodgy must BMCs in canal boats apparently are, This will come as a considerable shock to the huge numbers of people who have them and find them just as reliable as the many more modern offerings.

 

Is there actually a shred of evidence for this - I rather doubt it. Nosier maybe than some of the latest water cooled offerings, and maybe smokier, although nobody seems to find these reasons for damning some of the "vintage" engines that can be far worse in both those respects than a BMC.

[Proper Job]

No it's not just you!

 

i responded about BMCs because that's what the thread seemed to be about, but once we got on to Beta marinisation of a Ford I have also lost the plot.

 

I'm staggered though to learn just how unreliable and dodgy must BMCs in canal boats apparently are, This will come as a considerable shock to the huge numbers of people who have them and find them just as reliable as the many more modern offerings.

 

Is there actually a shred of evidence for this - I rather doubt it. Nosier maybe than some of the latest water cooled offerings, and maybe smokier, although nobody seems to find these reasons for damning some of the "vintage" engines that can be far worse in both those respects than a BMC.

 

Nothing wrong with a BMC engine. There are many, many of them out there giving tried and trusted service

 

I am looking forward to giving a certain 1.8 a damn good thrashing run in a couple of weeks time

 

[Tony Brooks]

The hire fleet I worked for in the 60s/70s had BMC 1.5s & 2.2s, Perkins 4-107 and 4-108, Penta MD2, Lister SL4s, and an SR (I think) 2. For inland hire work I preferred the 1.5s and about 3 years ago I met a chap on the GU with one of the boats I built in the early 70s, still with its original 1.5.

 

1.5s are simple engines with far less joints to leak than Listers with the same number of cylinders and when keel (or correctly sized tank) cooled do not suffer the overheating many of our Listers did (and one I hired years later when pushed hard and also do not have a nasty tendency to fill their sumps with diesel. Look after a BMC and it will be fine, especially if paired with a PRM hydraulic box. The downside is that to do major work properly needs two special tools. One for initially timing the in injector pump and one for torquing up the centre cylinder head nuts but in the latter case there is a way around it. There is also a hidden oil strainer and jet that needs cleaning every 5 to 8 years or when you first get the boat.

 

Far too often people blame the engine as being unreliable when they really mean something else like an inadequate cooling system or poorly specified electrics. Then there's the known reliability of a certain make of mechanical box that was frequently fitted to BMC 1.5s

 

I can't see the point of wasting internal space for an engine or fitting it so far back you have to crawl or twist yourself out of the back cabin. My boat always (apart from high summer) has a little water in the engine room bilge and its about 25 years old. (V poor cockpit drain system) and it is fine. You just have to ensure the water is pumped out regularly and that every few years the bilge is cleaned and painted. At least you can see it, unlike the under cabin bilge.

[John V]

 

I'm staggered though to learn just how unreliable and dodgy must BMCs in canal boats apparently are, This will come as a considerable shock to the huge numbers of people who have them and find them just as reliable as the many more modern offerings

 

OI !!!..........so far there has only been one anti BMC post

[Mike at Mayroyd]

Tony Brooks in post #29 referred to a "hidden oil strainer and jet" on BMC engines. Whereabouts on the engine is it?

[Tony Brooks]

Tony Brooks in post #29 referred to a "hidden oil strainer and jet" on BMC engines. Whereabouts on the engine is it?

 

The hexagons, one smaller one vertical and a larger one horizontal. Look below/under the back of of the exhaust manifold on the side of the cylinder block.

 

I think this rather neatly points out another reason why an engine type can get a name for unreliability. I am NOT having a pop at Mike because there are probably so many asking the same thing but one of the first things I did when I bought the boat was to buy or other wise get hold of an engine manual. No excuse of a BMC owner not to have one because its on a Norfolk Broads website. I then studied it for an evening to ensure there were no hidden gotyas that I did not know about. Now if the strainer on Mike's engine is blocked (its probably fine) so the injector pump and camshaft skew gears wear away does that make the 1.5 a problem engine or is it simply a lack of maintenance. This is a bit like the boaters who do nothing to inspect their drive plates and are the surprised when they fail.

[Proper Job]

I would suspect to, that something like this could easilly be missed as part of a professional service.

 

The mechanic drops the oil out of the engine and changes the cartridge filter - job done. He's no idea of the finer points of every engine built (unless he's very very expirenced)

 

I've only worked on a few BMC's over the years and had no idea of said strainer

[Tony Brooks]

I would suspect to, that something like this could easilly be missed as part of a professional service.

 

The mechanic drops the oil out of the engine and changes the cartridge filter - job done. He's no idea of the finer points of every engine built (unless he's very very expirenced)

 

I've only worked on a few BMC's over the years and had no idea of said strainer

 

 

A bit like the filter in the end of Vetus fuel pumps when they first came out then. That is why I bought the manual and I suppose I am a professional engineer. I am afraid thsi says rather more about the engineer and his informal CPD than it does about the engines. How may professionals would check how long since it was last done and advise that the internal pipe work (especially the injector leak off system) be removed and annealed How many would advise that it would be a good idea to check the injector pump bleed screws for security during a service. The customer may well decline to pay for such work but they should be given the option.

 

If you want a reliable engine of whatever make there is more to the annual service than change the oil and filters and press the alternator belts.

 

When I first went to work on the hire fleet it took me a couple of months to discover the strainer and jet so we checked the fleet and a number were clogged. How did I find out - I RTFM at lunch break rather than the Sun.

Edited May 12, 2014 by Tony Brooks

[alan_fincher]

 

OI !!!..........so far there has only been one anti BMC post

 

Fair comment.

 

I suppose I was factoring in the suggestions made in the earlier posts that they might be rubbish, as well as the one post that says they definitely are.

 

It is certainly not the case generally that they have heap of reliability problems that others don't suffer.

 

Very unlikely they would have been one of the mainstays of hire fleets for many years if that were the case.

[HappyBunny]

Hmmmm I have probably the most passionate, difficult, rewarding and frustrating love affair of my life (and I have had a few over the years ) with my BMC 1.5 .... but love it is

 

Mine has been "unreliable" .... but mainly for the reasons alluded to above .... inadequate / dodgy cooling and previous long term neglect / bodging ..... that said, the parts are available, relatively cheaply off the cut, and people are happy to work on them.

 

This is my first boat, and the unreliability has, in some ways, been a bonus because I have learned a huge amount and met some wonderful people along the way, who I might not have met without my numerous breakdowns. I have had to part with a fair amount of cash BUT the boat was cheap in the first place and I reckon I have spent less, learnt more and made more friends with the BMC than I might have done with a more expensive boat and a newer engine ..... well, that is what I tell myself to ease the pain .... swings and roundabouts.

 

Also, every time I have broken down, I have met someone else broken down nearby with a newer, shinier boat with a newer, shinier engine .... just keep away from the Berkhamsted triangle and Marston Doldrums Doles

 

I have a friend who ripped out the bulk head between his BMC engine and his bed so that the last thing he sees / smells at night and the first thing he sees / smells in the morning is his engine .... now that is love, bless him

[p6rob]

I know exactly what you mean HappyBunny. Now my 1.5 is running properly I've been impressed with how easily it starts.

15 seconds of glow plug and 3/4 throttle and it fires up with barely a puff of smoke now.

 

Rob

[alan_fincher]

Our BMC 1800 has been in the boat since it was built in 1995, being a "reconditioned" unit.

The evidence from the lack of broken paint seals is that it is only under our ownership that any of it has been taken apart, and so far the only significant work done to the engine itself, was dealing with head gasket problems a few years back. (There were hardly surprising, because until we had a new skin tank fitted, the previous one was woefully inadequate for serios use, and overheating must have been commonplace for the previous owner, as well as ourselves).

 

I would say it exists on a schedule of trying to do the right things at the right time, but has taken us very many miles now, and is certainly far from cosseted.

It leaks abit at various places, (always has, and no doubt always will), but the cost of an occasional bit of extra oil is insignificant comparer to pulling it apart to try and stop it ever happening.

It is not smart, but nor is it like the filth examples that one often sees, (sometimes in boats on brokerage!).

Access is pretty good in an "engine room", particularly to the side where most of the bits that require attention actually are.

A copule of pictures of it ......

 

If there were one single feature I could easily change on this engine, then it is a particularly poorly designed marinisation part, rather than anything originally fitted by BMC.

These bloody things are expensive, and we have now been through several over the years. I keep meaning to think of ways around this problem, but at the moment just make sure I always carry a spare.

[OldGoat]

I know of one particular boat with a Forde engine mounted to the side in it's own box.

Would yours be about 70 ft. long, possibly called Tricia?

 

If so quite a clever (?) arrangement with a long cardan shaft under the floor. Very quiet from the helm position anyway. I thought it was an XLD engine - I never took the cover off.

 

IMHO the problem with these and BMC engines is a complete lack of any torque - so not a lot of good if you need to stop in a hurry. In the times when these were popular for new builds, there wasn't much else available other than air cooled Listers / Petters and some others. Then Lister produced the Canal Star which was not a lot better.

 

 

[cereal tiller]

Our BMC 1800 has been in the boat since it was built in 1995, being a "reconditioned" unit.

 

The evidence from the lack of broken paint seals is that it is only under our ownership that any of it has been taken apart, and so far the only significant work done to the engine itself, was dealing with head gasket problems a few years back. (There were hardly surprising, because until we had a new skin tank fitted, the previous one was woefully inadequate for serios use, and overheating must have been commonplace for the previous owner, as well as ourselves).

 

I would say it exists on a schedule of trying to do the right things at the right time, but has taken us very many miles now, and is certainly far from cosseted.

 

It leaks abit at various places, (always has, and no doubt always will), but the cost of an occasional bit of extra oil is insignificant comparer to pulling it apart to try and stop it ever happening.

 

It is not smart, but nor is it like the filth examples that one often sees, (sometimes in boats on brokerage!).

 

Access is pretty good in an "engine room", particularly to the side where most of the bits that require attention actually are.

 

A copule of pictures of it ......

 

 

 

If there were one single feature I could easily change on this engine, then it is a particularly poorly designed marinisation part, rather than anything originally fitted by BMC.

 

These bloody things are expensive, and we have now been through several over the years. I keep meaning to think of ways around this problem, but at the moment just make sure I always carry a spare.

 

 

Make some brackets to support the pipework connected to those Bowman adaptors,if the pipes waggle around the rubber mouldings will fail prematurely.

 

CT

I know of one particular boat with a Forde engine mounted to the side in it's own box.

Would yours be about 70 ft. long, possibly called Tricia?

 

If so quite a clever (?) arrangement with a long cardan shaft under the floor. Very quiet from the helm position anyway. I thought it was an XLD engine - I never took the cover off.

 

IMHO the problem with these and BMC engines is a complete lack of any torque - so not a lot of good if you need to stop in a hurry. In the times when these were popular for new builds, there wasn't much else available other than air cooled Listers / Petters and some others. Then Lister produced the Canal Star which was not a lot better.

 

 

Do you happen to know the Torque produced by your Beta at ,say 2000 RPM,Mister Goat Sir?

 

CT

[alan_fincher]

Make some brackets to support the pipework connected to those Bowman adaptors,if the pipes waggle around the rubber mouldings will fail prematurely.

 

CT

 

Thanks,

 

It is actually a Polar one, although I suspect that doesn't change things that much.

 

What actually happens after a while is that they start to "baloon" up, and eventually stay "balooned" up, after which there is an indeterminate period of time before a small split starts to appear.

 

Our engine actually has a 7 psi pressure cap, (what Calcutt recommended for those marinised engines), but I sometimes wonder about running it unpressurised, (or if possible with an even lower pressure cap than it currently has). I can't help thinking that continuous 7 psi contributes to the failures.

[hopefulboater]

Am I the only one who is confused in this thread?

 

Is it a BMC or a BD3? Is it under a cruiser stern or in an engine room?

 

What on earth are we taliking about?

 

Sorry to confuse I looked at a lot of boats yesterday. My head was swimming by the evening!

One I looked at has a Ford Beta BD3 in its own engine room.

And a lot of the other boats had a BMC engine.... Which I have heard good and bad about but nothing actuallly specific until I asked for opinions here.

I know of one particular boat with a Forde engine mounted to the side in it's own box.

Would yours be about 70 ft. long, possibly called Tricia?

 

If so quite a clever (?) arrangement with a long cardan shaft under the floor. Very quiet from the helm position anyway. I thought it was an XLD engine - I never took the cover off.

 

IMHO the problem with these and BMC engines is a complete lack of any torque - so not a lot of good if you need to stop in a hurry. In the times when these were popular for new builds, there wasn't much else available other than air cooled Listers / Petters and some others. Then Lister produced the Canal Star which was not a lot better.

 

 

This is the one with the ford engine in main cabin.

http://www.whiltonmarina.co.uk/used-narrowboats/details/2855.aspx

[OldGoat]

 

 

Do you happen to know the Torque produced by your Beta at ,say 2000 RPM,Mister Goat Sir?

 

CT

 

Oooo, yes, young Sir; I have a curve somewhere (got a sinking feeling that you're about to shoot me down in flames)...

 

It's that shape that's important isn't it?

An automotive engine tends to produce its torque at higher revs: and an industrial unit's curve is flatter, so there's a better match between engine revolutions and power to the propeller?

[onionbargee]

BMC s are looked down on, but they are not much different to any modern off the shelf Kubota, or Yanmar, they are value for money, easy to fix, and the parts are cheap as chips.

 

One of the best engines ever made. What's not to like ?

[Tony Brooks]

 

Oooo, yes, young Sir; I have a curve somewhere (got a sinking feeling that you're about to shoot me down in flames)...

 

It's that shape that's important isn't it?

An automotive engine tends to produce its torque at higher revs: and an industrial unit's curve is flatter, so there's a better match between engine revolutions and power to the propeller?

 

Unfortunate I have no torque curves for the 1.5 and a selection of other industrial engines but as the torque is going to determined by the mean effective pressure and the crank throw (half the stroke) I would expect the BMC, being an inch under square (having a stroke an inch longer the the bore) to develop more torque than a modern square or over square industrial engine. I suppose the siamesed inlet and exhaust ports will reduce the volumetric efficiency and that would reduce the MEP and thus reduce the overall torque and I suspect it would flatten the curve because the inlet and exhaust restrictions would be more pronounce at higher speeds. I very much doubt the curves for a Kubota and BMC would be significantly different in shape. In fact I have been trying to think what you could do to an engine to significantly alter the flatness of the torque curve apart from monkeying around with fuel delivery in the centre section but that would almost certainly require electronic injection control. In fact I can not see any advantage in hobbling the power output in the middle section of the curve.

 

Because of the siamesed ports the BMC is likely to produce less torque than an engine with single ports but I do not see that has much bearing on the question of it being a "good" or "bad" engine design. The fact the basic Harry Bathgate combustion chamber design lasted in production from the late1940s for the rest of the century suggest it is a "good" engine.

 

I suppose I am rambling now.

[Paul C]

Do you happen to know the Torque produced by your Beta at ,say 2000 RPM,Mister Goat Sir?

 

CT

 

Why does a boat engine need low down torque?

 

Surely at low speeds, the throttle is also only partly open, its not like a tractor or a car where there are a number of gears and being able to produce torque low down, saves changing down gears and is more economical; or gives good acceleration. And since high speed/high power is only really used for maneouvring a canal boat....

[cereal tiller]

 

Why does a boat engine need low down torque?

 

Surely at low speeds, the throttle is also only partly open, its not like a tractor or a car where there are a number of gears and being able to produce torque low down, saves changing down gears and is more economical; or gives good acceleration. And since high speed/high power is only really used for maneouvring a canal boat....

Correct.

 

I was teasing Old Goat,I can only assume he would enjoy owning an Austin Healey 3000 which would involve lengthy conversations about Torque,high lift Cams and Limited Slip Differentials!

 

CT

[alan_fincher]

IMHO the problem with these and BMC engines is a complete lack of any torque - so not a lot of good if you need to stop in a hurry. In the times when these were popular for new builds, there wasn't much else available other than air cooled Listers / Petters and some others. Then Lister produced the Canal Star which was not a lot better.

 

Not sure of the accuracy of my source but, (sticking with common types all nominally about 35HP).......

 

BMC 1.8 80 ft lbs @ 2,400 rpm

 

Beta 35 81 ft lbs @ 2,400 rpm

 

Isuzu 35 65 ft lbs @ 1,800 rpm

 

Vetus M4.15 77,5 ft lbs @1,800 rpm

 

 

So torque wise I would say the older BMC is well up there with the more modern industrial or agricultural based engines, and actually better than some popular brands.

 

Our BMC 1.8 stops the boat just fine - quickly if it needs to.

[peterboat]

The issue for me is its a converted petrol engine and not done well in cars and vans it was slow and unreliable. The MOD trialed both the petrol and diesel sherpa minibuses it comes to something when you have to ask the passengers to push up a hill yes the diesel version. And you cant compare kubota and Yanmars two of the best most reliable industrial diesels in the world to a BMC because they have had no industrial applications that I have heard of. As someone else said they were put in boats because no one else wanted them and they were cheap. Keith has one its cost a fortune it was a well maintained boat when he bought it he hasnt scrimped on servicing and yet still it breaks down headgaskets starters oil leaks bottom end combustion chambers falling out and injector faults. Steves has had the head gasket twice and now knocks so bad that that a new engine is on the cards not a BMC. And then we have a 1.5 in the 9 years I have known it its never finished a journey. Last but not least is an old broads boat never broke down but always followed by clouds of blue smoke and that is after a watercooled exhaust, its now sold and is being re-engined. I know that their are a lot of BMCs out there doing good service but for me I would not buy a boat with one

 

Peter

[David Schweizer]

BMC 1.5 65

 

Quote

BMC 1.8 80 ft lbs @ 2,400 rpm

Beta 35 81 ft lbs @ 2,400 rpm

 

Isuzu 35 65 ft lbs @ 1,800 rpm

 

Vetus M4.15 77,5 ft lbs @1,800 rpm

 

Not sure of the accuracy of my source but, (sticking with common types all nominally about 35HP).......

 

 

So torque wise I would say the older BMC is well up there with the more modern industrial or agricultural based engines, and actually better than some popular brands.

Our BMC 1.8 stops the boat just fine - quickly if it needs to.

 

BMC 1.5 64 ft lbs @ 1,900 rpm. So similar to the Isuzi 35