Thorneycroft 1.5 - Are they any good?

[RichardH]

Looking at a Colecraft 55ft with a Thorneycroft 1.5

 

I've been a Lister die hard to date and had no experience of water cooled modern stuff !

 

What are they like and will they happily push a boat of this length up the Trent or across the Ribble link.

[bottle]

Richard

 

Thornycroft are not the actual builders of the engine they are the converters, depending on age/date of manufacture it will possibly be BMC.

[Tony Brooks]

Looking at a Colecraft 55ft with a Thorneycroft 1.5

 

I've been a Lister die hard to date and had no experience of water cooled modern stuff !

 

What are they like and will they happily push a boat of this length up the Trent or across the Ribble link.

 

 

MODERN STUFF!!!!

 

Not bad for an engine that started life in the 1940s as an Austin engine and them got dieseliefied in the late 50s/early 60s. Its neigh on a vintage engine.

 

I think I read you had to be capable of maintaining 6 knots for the Ribble link and if so I have some doubts you will do that, but I am sure you will get well over 4 (my 34bhp gives about 5 by GPS on the Trent).

 

I am sure this is the BMC and in its day was the mainstay of many hirefleets. Simple, robust and its about the only one a total amateur can re-time the injection pump on (for the techies - unless the cam drive has excess wear). As far as I can see parts are still available form a number of suppliers.

 

Do give it a prolonged test at full power, on a Colecraft hull I do not expect overheating caused by an undersized skin tanks so if it does it may well be head gasket problems (not unknown on these engines, but not that common either).

 

My 34 bhp 1500cc Bukh copes very well with a 54 ft hull and although the torque curve is a bit different any 1500 cc diesel shoddily give simmilar performance as long as the prop is well matched.

 

If by some weird chance it is squirting water out of its exhaust make sure the surveyor tells you if it is direct cooled if so it may be better to walk away (reasons a bit technical and complicated, but those ones do tend to crack heads).

 

 

Tony Brooks

[Mac49]

I know someone who bought a Thonycroft 1.5 about 8 or 9 years ago and that's mitsubishi based. They're please with it and have had no problems, it's in a 40 ft boat.

[John Orentas]

Hi Richard.

 

I agree with Tony and others, if it has any age the engine is most likely to be a BMC or Leyland or whatever you choose to call it. I think Tony is being very pessimistic about the power output however. I remember the time when the 'comics' would have articles concerned with the 'grossly over-powered' four cylinder water cooled units in comparison to the virtual standard of the time, the Lister two and there cylinder engines.

 

I have been on the Ribble and the Trent and have been accompanied by all kinds of craft with various sizes of engine, you will have no problems at all as long of course it is in reasonable condition, yes keel cooling is better but don't write the others off.

 

Do a 'Search' on keel cooling, keel tanks there is lot's of stuff on here.

[Tony Brooks]

Hi Richard.

 

I agree with Tony and others, if it has any age the engine is most likely to be a BMC or Leyland or whatever you choose to call it. I think Tony is being very pessimistic about the power output however. I remember the time when the 'comics' would have articles concerned with the 'grossly over-powered' four cylinder water cooled units in comparison to the virtual standard of the time, the Lister two and there cylinder engines.

 

I have been on the Ribble and the Trent and have been accompanied by all kinds of craft with various sizes of engine, you will have no problems at all as long of course it is in reasonable condition, yes keel cooling is better but don't write the others off.

 

Do a 'Search' on keel cooling, keel tanks there is lot's of stuff on here.

 

 

The power of a BMC1.5 is a bit over 30bhp, but that is not really material in this context. IF there is a minimum speed of 6 knots on the Ribble link my own experience with a very similar sized boat and similarly powered engine indicates that any engine in this power range might be marginal. If there is no minimum speed requirement then I would have no hesitation in using a BMC 1.5 (or any other similar powered engine (except those with elastic band timing which are fortunately very few) for the duties mentioned. However one does have to work the tide/current and it may be best to do one such trip with someone with experience of navigating around obstructions in higher currents.

 

My son scared the pants off me doing Teddington to Limehouse on a falling tide because he would keep cutting across bridge piers instead of lining up with lots of room in hand in case of emergencies. However the 35bhp engine was absolutely fine, including the turn across the tide rip into Limehouse so it should be OK for any foreseeable trip.

 

I have no problems with heat exchanger cooling, but automotive engines and direct, raw water cooling can suffer problems relate to scale on the hotspots in the water jacket. This can lead to cracked heads, so it is best to take great care over this type of cooling system. I am sure it will not be direct cooled though.

 

As I have said before I have an article from Waterways World that states a 60 odd ft narrowboat only requires about 2 hp to drive it at canal speed, so even those Listers were overpowered. I suspect it must have been a shock to go from an Lister with maximum RPM of 2000 rpm to a BMC 1.5 at double that, but the BMC is still a reliable and robust engine. RCR ltd say they still account for about 60% of canal boat engines.

 

 

 

Tony Brooks

[John Orentas]

If I remember, that 6 knot thing is an advisory figure on the application form. We must bear in mind that in deep, wide, still water there will be very few narrowboat that are not capable of that speed. Incidentally on the Ribble Link if you are delayed for some reason and miss the 'tide widow' you will simply be sent on to Preston in one direction or told to moor up on the river Douglas in the other.

[Mac49]

This link might be useful if it's a recent engine, it's got some figures and stuff.

http://www.thornycroftengines.co.uk/products.htm

[RichardH]

I think it is a BMC

[DHutch]

Yeah, tbh, you can do the ribble with less...

 

We actually went via preston, as we thought it might be a bit close, but even though we TOTALLY ballesed it up, and almost ended up anchoring in the preston estary to prevent being carried out to sea (0.1mph recorded on the gps crawling up 4ft from the bank) we got there for tea and just nipped down to the link the following morning.

 

 

Daniel

[NB Alnwick]

If the engine is based on the basic BMC/Leyland 1500/1800 you will benefit from an ample supply of affordable spare parts and service items. So you will be able to keep it going long after many later engines have been scrapped for want of service parts.

 

We have a tuned petrol variant of the same engine in our 1967 MGB GT - it produced 85 BHP @ 5,500 RPM on a rolling road dynamometer - which means that the power output was measured at the rear wheels and includes all the transmission drag!

 

If only the parts for a Kelvin K3 were as easy to source and nearly as cheap . . .

[Proper Job]

We had a 1.5 Thorneycroft based on the BMC in a 50 footer. It was used on the Thames for most of its life and would punch up against fast running streams with no bother.

 

We also 'over-ran' a trip from Limehouse to Teddington and had to overcome the out going tide. The old girl was running virtually flat out for well over an hour and came up with the goods.

 

Good reliable work horses!

 

 

Steve

[Theo]

Hi Richard.

 

I agree with Tony and others, if it has any age the engine is most likely to be a BMC or Leyland or whatever you choose to call it. I think Tony is being very pessimistic about the power output however. I remember the time when the 'comics' would have articles concerned with the 'grossly over-powered' four cylinder water cooled units in comparison to the virtual standard of the time, the Lister two and there cylinder engines.

 

I have been on the Ribble and the Trent and have been accompanied by all kinds of craft with various sizes of engine, you will have no problems at all as long of course it is in reasonable condition, yes keel cooling is better but don't write the others off.

 

Do a 'Search' on keel cooling, keel tanks there is lot's of stuff on here.

 

I am getting quite attached to Theodora's raw water cooling but I hasten to add it is not direct raw water.

 

Nick

[RichardH]

If the engine is based on the basic BMC/Leyland 1500/1800 you will benefit from an ample supply of affordable spare parts and service items. So you will be able to keep it going long after many later engines have been scrapped for want of service parts.

 

We have a tuned petrol variant of the same engine in our 1967 MGB GT - it produced 85 BHP @ 5,500 RPM on a rolling road dynamometer - which means that the power output was measured at the rear wheels and includes all the transmission drag!

 

If only the parts for a Kelvin K3 were as easy to source and nearly as cheap . . .

 

That's good - one of the old sea dogs I know who said 'steer clear' said parts supply could be an issue. Where are the best places to source parts?

 

Thanks for all the information folks.

[bottle]

Have a look here Calcutt boats not used them myself and have no connection.

[Tony Brooks]

Have a look here Calcutt boats not used them myself and have no connection.

 

 

Also ASAP supplies and AMC (which I think may be in the same setup as Thornycroft).

 

As far as I know the 1.5 is still being manufactured in India and the 1.8 in Turkey, so while there are lots about I can not see spares being that difficult. Service items available form any decent motor factors.

 

 

Tony Brooks