Cross country DMUs upgraded to "more powerful" Leyland 680 engines (1978 on)

[Justin Smith]

I was reading through my Ian Allan 1978 BR Motive Power combined Volume (bought at Oxford market for £3 ! ) and, at the start of the Diesel Multiple Units section I read this :

"Gloucester and Swindon-built cross country units are having their BUT/AEC engines replaced with the more powerful Leyland 0680"

However I have both engines down as 150bhp at 1800rpm and the introduction dates for the engines as both being "early 1950s" with capacity as 11.3L for the BUT L type engine and 11.1L for the 0680 engine (possibly a typo ? ) also known as a BUT L type.

Can anyone throw any light on this apparently inconsistent story ?!?

 

[Pyewipecarshed]

I was always under the impression that the conversion was done because the AEC engine had gone out of production and spares were getting scarce, whereas at the time Leyland were still producing the 0680.

 

[Justin Smith]

I was always under the impression that the conversion was done because the AEC engine had gone out of production and spares were getting scarce, whereas at the time Leyland were still producing the 0680.

That sound more likely to me.

 

[hexagon789]

I was reading through my Ian Allan 1978 BR Motive Power combined Volume (bought at Oxford market for £3 ! ) and, at the start of the Diesel Multiple Units section I read this :

"Gloucester and Swindon-built cross country units are having their BUT/AEC engines replaced with the more powerful Leyland 0680"

However I have both engines down as 150bhp at 1800rpm and the introduction dates for the engines as both being "early 1950s" with capacity as 11.3L for the BUT L type engine and 11.1L for the 0680 engine (possibly a typo ? ) also known as a BUT L type.

Can anyone throw any light on this apparently inconsistent story ?!?

Beginning in January 1976, the 101s, 119s and 120s had their original AEC 220 engines replaced with Leyland 680H. The 680H was rated at 200bhp for road use, downrated to 181bhp at 1800rpm for rail use.

The Leyland engines already in use were plain 680s, rated at 150bhp.

This was due to the reliability/parts issues mentioned.

 

[Justin Smith]

Beginning in January 1976, the 101s, 119s and 120s had their original AEC 220 engines replaced with Leyland 680H. The 680H was rated at 200bhp for road use, downrated to 181bhp at 1800rpm for rail use.

The Leyland engines already in use were plain 680s, rated at 150bhp.

This was due to the reliability/parts issues mentioned.

Very interesting.
I thought the H just stood for Horizontal ?
I have down in my database that the 680 produced 175bhp at 2000rpm in a 1972 Leyland Atlantean and the same in a 1977 Leyland Leopard ?

 

[Fleetwood Boy]

Very interesting.
I thought the H just stood for Horizontal ?
I have down in my database that the 680 produced 175bhp at 2000rpm in a 1972 Leyland Atlantean and the same in a 1977 Leyland Leopard ?

My understanding too, I don't think anything changed with the O680 engine, although it could be downrated as with all engines - however I do vaguely remember something like a PowerPlus version, which may have been uprated somehow? Interesting that it was a long time before buses started regularly using the O680, buses contemporary to the first gen DMUs all used O600 engines.

 

[Clarence Yard]

The Leyland 0680 and AEC 220 had the same 150hp rating and the replacement 0680 engines for the conversion were also 150hp.

At Reading, the 0680 was the standard 150hp engine that we used on all classes, which included 101, 117, 119 and 121 sets. The only AEC engined car we had was the DMBS of the (now preserved) Derby Lightweight Ultrasonic Unit.

I don’t know where the idea that the Leyland 0680 were “more powerful” on rail came from! Did someone look at the bus rating and then made an assumption?

 

[hexagon789]

From the Railcar website:

Re-engining Programme​

At the end of 1975 British Rail ordered 300 Leyland 680H diesel engines from Leyland Truck & Bus. The £1¼ million order was to replace the engine in vehicles from Classes 101/119/120. The engine replacement was not part of the refurbishment programme then underway. It was due to the poor availablilty of spares for the original AEC engines.

Delivery commenced in January 1976 at a rate of ten engines a week. They were supplied complete with Leyland fluid couplings and were to drive through the existing mechanical transmissions.

It was quoted that the 680H was the horizontal version of the 680 in use in the majority of London buses, and that for traction use, the engine was de-rated from over 200hp to 181hp, and that even in this de-rated form the new engines provided 20% more power than the previous AEC equipment.

Unfortunately the source of said 'quote' is not given.

 

[Fleetwood Boy]

From the Railcar website:



Unfortunately the source of said 'quote' is not given.

And is also wrong in saying most London buses used Leyland 680 engines.

 

[Magdalia]

I have been trying to find this in some very old National Archives research notes.

In autumn 1974 there was a problem identified getting spares for obsolete DMU engines of 2 types though not specified. An order for 300 new Leyland engines went through the Investment Committee in late 1974. I didn't record any details of how the new engines would be used.

This could still be consistent with first deliveries in January 1976 as order to delivery lags in the 1970s UK engineering industries could be very long.

There was a further order of 200 engines in 1980, it does say that these were for Metro Cammells (class 101).

So it looks like the Gloucester/Swindon (class 119/120) and Metro Cammells (class 101) were two separate projects.

 

[matchmaker]

The Leyland O600 was a 9.8 litre engine producing 125bhp. The O600 "Semi Power Plus" produced 130bhp. The O680 was 11.1 litres producing 150bhp.

 

[Justin Smith]

Was looking through my 1986 "Platform 5" stock book and it had the "680/1" engine (as fitted to many 1st generation DMUs) at 150hp.