Which one was the sweetheart?

[Wainlode]

Hi all, I'm new to this forum and this is my first post. Any opinions happily received.

 

I am speculating on a couple of boats, one of which has an unspecified Thorneycroft engine in the description. I assume it will be a BMC of some sort.

 

A thought crossed my mind: what was the nicest BMC engine? Perhaps in terms of power output, fuel consumption, ease of maintenance, general reliability or perhaps more importantly here in 2019, the availability of spares?

 

Maybe the better question is are there any to avoid?

 

Thanks in advance.

 

[Boater Sam]

The 1.5D and 1.8D are still well supported for spares, both were until recently produced new in India and Turkey respectively.

The 2.2 less so, thought to have a weak crankshaft. The various Land Rover diesel engines, 2.9, 2.25 and 2.5 never really caught on for boats. The big 6 cylinder ones are rare in narrowboats.

Power wise the 1.8D is ample for even longer boats, the 2.2 is a bit of an antique. Even a 1.5D will push a 70 foot boat just fine on canals, a bit underpowered for rivers.

Fuel consumption in a narrow boat is more dependant on speed rather than capacity. One and a half litres an hour is about the maximum, some smaller boats will  run to a litre an hour maybe.

If you are considering a wide boat, none of the above are suitable as they have not enough power.

They are all reliable if maintained, hence the vast numbers in use, Spares are generally reasonably priced.

None are particularly quiet or clean burning by modern standards, they do not comply with emission standards but as yet this is no drawback for boats.

But I like them, others will hate them, the snobs will only have chunk chunk engines and look down their noses.

Edited April 28, 2019 by Boater Sam

[alan_fincher]

Not all Thorneycroft engines are marinisations of the BMC.  They did others.  Mitsubishi, for example, I think, but could be wrong.

The 1.5 and 1.8 BMCs are suitable narrow boat engines.  I would say the 2.2 and 2.5 engines very much less so.

[Boater Sam]

Agree, some later Thorneycrofts are Mitsubishi, they lack the distinctive BMC Mini rocker box design.

[Wainlode]

Hi again

 

thanks for the replies, most helpful. I have heard of Mitsubishi in connection with Thorneycroft, and since they are Japanese I immediately think 'reliable'. Agree? (I know its a BMC forum)!

 

Also one other question: are all BMCs marinised by Thorneycroft, or are there any marinisation brands worth steering clear of?

 

And finally, knowing I am at risk of asking too many questions...any gearboxes to avoid / prefer?

 

 

[Boater Sam]

15 minutes ago, Wainlode said:

Hi again

 

thanks for the replies, most helpful. I have heard of Mitsubishi in connection with Thorneycroft, and since they are Japanese I immediately think 'reliable'. Agree? (I know its a BMC forum)!

 

Also one other question: are all BMCs marinised by Thorneycroft, or are there any marinisation brands worth steering clear of?

 

And finally, knowing I am at risk of asking too many questions...any gearboxes to avoid / prefer?

 

 

The marinisers  do very little to the base engine, its down to alternators and exhaust manifolds really. Fabricated steel manifolds are a no no.  Some put extra weight on the flywheels to aid smooth low speed running, a good idea.

Gearboxes, humm, I  prefer hydraulic boxes, PRM 160, 260, 280, are cast steel, bomb proof, Delta and 150 are OK but ally cased.

The lower PRM mechanical boxes are all right but do wear out.

Personally I detest Hurth mechanical boxes

TMC, Borg Warner etc are less popular but reasonable.

[MtB]

37 minutes ago, alan_fincher said:

The 1.5 and 1.8 BMCs are suitable narrow boat engines.  I would say the 2.2 and 2.5 engines very much less so.

 

Out of interest, what is wrong with the 2.2 and 2.5 engines, other than being unnecessarily large for a NB?

 

Especially bearing in mind the trend for fitting Beta 38 and 43 engines in 57ft narrowboats?

 

[john6767]

9 minutes ago, Mike the Boilerman said:

 

Out of interest, what is wrong with the 2.2 and 2.5 engines, other than being unnecessarily large for a NB?

 

Especially bearing in mind the trend for fitting Beta 38 and 43 engines in 57ft narrowboats?

 

Beta 38 is 1500cc, Beta 43 is 2000cc.

[MtB]

Just now, john6767 said:

Beta 38 is 1500cc, Beta 43 is 2000cc.

 

What power is a BMC 2.2?

 

 

[TheBiscuits]

9 minutes ago, Mike the Boilerman said:

Especially bearing in mind the trend for fitting Beta 38 and 43 engines in 57ft narrowboats?

You are behind the times Mike, no self respecting top trumps player would consider less than a 43 these days, and bigger is preferred, just in case they ever go near one of those river things ....

 

(I have a Beta 38 in my 45 foot boat but only a 17" eggwhisk prop so it doesn't count ...)

[MtB]

2 minutes ago, TheBiscuits said:

(I have a Beta 38 in my 45 foot boat but only a 17" eggwhisk prop so it doesn't count ...)

 

I had a Beta Greenline 30 in my 40ft NB and I have to say, performance was PATHETIC. Due mainly in my opinion to the 15" blade.

 

Swapping it for a 68ft boat with a Beta 35hp BD3 with 21" blade was a revelation in performance. WHAT a fast and nimble boat before I fitted the K1 ! 

 

I put it all down to blade diameter.

 

 

[MtB]

9 minutes ago, TheBiscuits said:

(I have a Beta 38 in my 45 foot boat but only a 17" eggwhisk prop so it doesn't count ...)

 

I'd also compare this with the Kingfisher 30hp I had in my 45ft boat REGINALD for a while, spinning a 24" blade. Again spectacularly fast and agile. Big blade again...

 

 

[Wainlode]

Just want to say thanks for the input, especially from Mike. Props are a very complicated subject! One thing at a time for me.

[MtB]

5 minutes ago, Wainlode said:

Just want to say thanks for the input, especially from Mike. Props are a very complicated subject! One thing at a time for me.

 

Yer welcome. 'Tis my view that the trend towards ever more powerful engines is due to the ever reducing draft (and hence reducing blade diameter) of modern NB shells. 

 

Pic a nice deep drafted boat with a big diameter blade and even a low power engine will have it racing about like a rocket. 

 

 

 

[Tony Brooks]

41 minutes ago, Boater Sam said:

The marinisers  do very little to the base engine, its down to alternators and exhaust manifolds really. Fabricated steel manifolds are a no no.  Some put extra weight on the flywheels to aid smooth low speed running, a good idea.

Gearboxes, humm, I  prefer hydraulic boxes, PRM 160, 260, 280, are cast steel, bomb proof, Delta and 150 are OK but ally cased.

The lower PRM mechanical boxes are all right but do wear out.

Personally I detest Hurth mechanical boxes

TMC, Borg Warner etc are less popular but reasonable.

 

Personally I learned to detest TMP boxes that were fitted to some BMC1.5s. They had alloy cases with a cooling water gallery formed in the joint. That blocked up. They also used pop rivets on some clutches that failed. I did like the Borg Warner 35s though.

 

Don't Vetus fit TMC boxes that bang into gear, wear out, and have limited running in idle times? Agree about Hurths.

[TheBiscuits]

32 minutes ago, Mike the Boilerman said:

I put it all down to blade diameter.

Me too.   My clearance between skeg and uxter plate allows 2" clearance on a 17" prop, which smells about right. 

 

I was looking a buying a longer pitched prop off the forum last year, but @mrsmelly beat me to it as he wanted a spare eggwhisk for his overly long and heavy boat that he doesn't want to take anywhere this year ... 

 

(No I'm not bitter ... why do you ask? )

[Wainlode]

I broadly agree, although the bigger the prop the greater the amount of energy required to push it. The other important factor is pitch - too much and it will add a greater strain at the gearbox (think trying to pull away in third gear). The saving grace is that canal boats operate at relatively low RPMs.

 

This one may be too large for a narrowboat.

 

 

 

[mrsmelly]

32 minutes ago, TheBiscuits said:

Me too.   My clearance between skeg and uxter plate allows 2" clearance on a 17" prop, which smells about right. 

 

I was looking a buying a longer pitched prop off the forum last year, but @mrsmelly beat me to it as he wanted a spare eggwhisk for his overly long and heavy boat that he doesn't want to take anywhere this year ... 

 

(No I'm not bitter ... why do you ask? )

I forgot about that  I cant even remember what size it was? 17 by somett or other. I will prob just leave it in the spare parts bin. I gave him 100 squids iirc. you can have it for 50 squids if you pass buy some day, I reckon my boat will sink if I buy any more spares lol.

[alan_fincher]

I'd agree that given the choice a PRM Newage hydraulic box is the best gearbox.  The small mechanical ones seem clunky by comparison.  Hurth seems to be far less universally liked.

 

As to BMC marinisations, the 1.5 and 1.8 B series engine were supplied in large numbers by a series of reputable marinisers, and as the move from air-cooled Listers to something water cooled, queiter, and with more cylinders became the norm in the narrow boat building business, they became almost the de facto narrow boat engine for many years, being used successfully in large numbers of both private and hire boats.

 

By comparison the 2.2, 2.5 etc engines have always been used in only small numbers in narrow boats, and seem to have been far less well supported by good marinisers.  Many of those that do exist seem to be less than perfect conversions, often amateur ones.  You really shouldn't need the power these things kick out in a narrow boat, and hence they also tend not to get worked hard enough.

[Slim]

When I fitted VS out from a bare shell too many years ago it was, for personal reasons, a project. To be honest money didn't come into the equation. I chose to rebuilt a BMC 1.8D from a £100 scrapyard job. (the starter cost an extra fiver). Never regretted it for a minute. It may not be the most 'green' or economical engine out there but it's reliable. The only major work I've had to do on it was new valve guides a couple of years ago and that was because of bum advice from an 'expert' when originally rebuilding it. Spares are cheap and readily available. Motor factors can still satisfy 90% of your needs. Surprisingly the one thing that's not instantly available at a sensible price is CC oil. It's easily obtained with a little shopping around on line.  

I would have no inherent reservations in buying a boat with a BMC 1.8

[Athy]

14 hours ago, alan_fincher said:

Not all Thorneycroft engines are marinisations of the BMC.  They did others.  Mitsubishi, for example, I think, but could be wrong.

 

You are not. My Springer had a Thornycroft which was a marinised Mitsubishi. The boat was a (believed) 1987 build, I think that by then the B.M.C. engines were no longer in production (in Britain, at any rate) so they had to find a replacement.

[Bee]

Hmm, propellers. Funny things, witchcraft and magic.  Its probably better when fitting out a boat to work backwards from the prop. Say a boat weighs 15 tons, and is a fat or thin, longish or something in between, it should be possible to work out the shove it needs, then order from a small range of propellers that fit that will provide that shove at say 1000 rpm then look at a chart of engines that have got the oomph to spin the prop at that speed. Anyway gearboxes, the little mechanical ones are awful. Engines, BMC's are perfectly ok, in fact anything that is running ok is likely to continue running well with care and attention.

[Boater Sam]

Best advice is from a firm like Crowthers in Oldham we can size a prop and make it. They make high performance props with a larger blade area too, handy if you cannot fit a larger diameter due to skeg clearance.

BMC 1.8D 18" X 10.5  High performance works very well.

[Athy]

30 minutes ago, Boater Sam said:

Best advice is from a firm like Crowthers in Oldham we can size a prop and make it. They make high performance props with a larger blade area too, handy if you cannot fit a larger diameter due to skeg clearance.

BMC 1.8D 18" X 10.5  High performance works very well.

I hadn't realised that you worked for Crowther's, so I'm pleased to be able to tell you that our 22" model has always given good service. Mel Davis, who built our boat, always uses them and says "They haven't got one wrong yet".

[NewCanalBoy]

Why the dislike for Hurth boxes ?

 

What's the issue/problem ?

 

Are they reliable but just clunky/noisey ?