CM road test of the 510 Powered Bufffalo. IIRCeither CM or Truck road tested the 510 or 511 Buffalo and reported that it had knocked the Gardner 8 LXB of its perch for fuel efficiency over the Scottish Test Route.
I think the answer to the L12 being underpowered is more than likely due to it having low compression cylinder packs meant for a turbocharged engine, when a naturally aspirated engine needs higher compression, knowing how BL went about things in those dark times it makes sense. It would also explain their longevity, low compression means lower heat in the top end, so that eliminates a lot of top end wear and failures and the rings and liners having less pressure will help increase their longevity too, the same goes for the big ends and mains, which only leaves the ancillary components to go wrong at the normal rate.
When I lived in Cambridgeshire a local farmer had a L12 Bison, which he’d had from new, and it had been well looked after, although it didn’t do a lot of work, probably 6 or 7 months a year on grain and sugar beet carting. I helped him out in the beet campaign on my days off for a few years, usually 5 or 6 loads of beet daily into Bury St Edmunds sugar factory. The L12 engine was ideal for the Bison running at 24 tonnes gvw.
DEANB:
Leyland Buffalo road test with TL11 engine producing 209 BHP from 1979.Click on pages twice to read.
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That version of the TL11 is barely any more powerful than the Power Plus 680, from nearly two decades before, yet it needs a turbocharger to make those extra 9 hp. You would have thought that they would have saved the cost of the blower and pipework. Was there a 260bhp TL11 Buff? That would have made sense- a fast, cheap no-frills motor for sensible British operators.
cav551:
CM road test of the 510 Powered Bufffalo. IIRCeither CM or Truck road tested the 510 or 511 Buffalo and reported that it had knocked the Gardner 8 LXB of its perch for fuel efficiency over the Scottish Test Route.
The 510 gives a very good account of itself, by my reading of the text. If they could have made it reliable…
PS check your emails. 
[zb]
anorak:DEANB:
Leyland Buffalo road test with TL11 engine producing 209 BHP from 1979.Click on pages twice to read.
3
2
1
0
That version of the TL11 is barely any more powerful than the Power Plus 680, from nearly two decades before, yet it needs a turbocharger to make those extra 9 hp. You would have thought that they would have saved the cost of the blower and pipework. Was there a 260bhp TL11 Buff? That would have made sense- a fast, cheap no-frills motor for sensible British operators.
I think there was a 260 bhp Cruiser
ramone:
[zb]
anorak:DEANB:
Leyland Buffalo road test with TL11 engine producing 209 BHP from 1979.Click on pages twice to read.
3
2
1
0
That version of the TL11 is barely any more powerful than the Power Plus 680, from nearly two decades before, yet it needs a turbocharger to make those extra 9 hp. You would have thought that they would have saved the cost of the blower and pipework. Was there a 260bhp TL11 Buff? That would have made sense- a fast, cheap no-frills motor for sensible British operators.
I think there was a 260 bhp Cruiser
The TL11C was offered in the Cruiser rated at 260bhp Tyneside
From the late 1970s and the first years of T45 Series production British Leyland had actually got a decent range of engines after the debacle of 10 years before. TL12, TL11, L12 all were good fleet spec truck engines covering power outputs from 200 to 280 bhp. Even the turbo-charged 6.98 in the rigids was a decent unit. By then BL had probably lost lots of its previously loyal customer base and senior management was set on the bought-in engine policy for premium Roadtrain models. Fast forward another decade and the British and European market had changed its thinking and proprietary engine models were in decline. British Leyland got most of its truck policy wrong from the early 1970s until its demise.
gingerfold:
From the late 1970s and the first years of T45 Series production British Leyland had actually got a decent range of engines after the debacle of 10 years before. TL12, TL11, L12 all were good fleet spec truck engines covering power outputs from 200 to 280 bhp. Even the turbo-charged 6.98 in the rigids was a decent unit. By then BL had probably lost lots of its previously loyal customer base and senior management was set on the bought-in engine policy for premium Roadtrain models. Fast forward another decade and the British and European market had changed its thinking and proprietary engine models were in decline. British Leyland got most of its truck policy wrong from the early 1970s until its demise.
Was the TL11 a reworked 680 then similar to the AV760 TL12 scenario
ramone:
gingerfold:
From the late 1970s and the first years of T45 Series production British Leyland had actually got a decent range of engines after the debacle of 10 years before. TL12, TL11, L12 all were good fleet spec truck engines covering power outputs from 200 to 280 bhp. Even the turbo-charged 6.98 in the rigids was a decent unit. By then BL had probably lost lots of its previously loyal customer base and senior management was set on the bought-in engine policy for premium Roadtrain models. Fast forward another decade and the British and European market had changed its thinking and proprietary engine models were in decline. British Leyland got most of its truck policy wrong from the early 1970s until its demise.Was the TL11 a reworked 680 then similar to the AV760 TL12 scenario
The TL11 was more of a re-working of the Leyland O.680. Leyland had already turbo-charged that engine in 1968 naming it the 690, which was somewhat confusing as AEC had the A690 in vertical and horizontal layouts, both of which were also turbo-charged for certain applications, AEC’s 690 had been replaced in 1965 by the A691 and A760. Returning to the Leyland 690 it was basically a O.680 with a turbo-charger and it gained Leyland useful knowledge about turbo-charging for lorry applications. The 690 in the Ergo cab wasn’t a great success because of the usual problems of overheating and head gasket failures. The TL11 was really the 690 with a bit more development, and of course it was fitted under the raised, high-datum Ergo cab.
ramone:
you would still expect to be able to get more than 203 bhp out of a 12.47 litre engine though
Turbocharghing adds around 30% over NA.Intercooling adds significantly more to that figure.
203 sounds close enough to around 30% less than the TL12.
The L12’s specific power deficit, at 100 rpm higher, v both Rolls Eagle 220 and ■■■■■■■ 220 seems to reflect the specific torque deficit at 45 lbft per litre v around 50 lbft per litre.
Which can arguably largely be attributed to the Rolls’ and ■■■■■■■■ leverage at the crank advantage.
newmercman:
I think the answer to the L12 being underpowered is more than likely due to it having low compression cylinder packs meant for a turbocharged engine, when a naturally aspirated engine needs higher compression, knowing how BL went about things in those dark times it makes sense. It would also explain their longevity, low compression means lower heat in the top end, so that eliminates a lot of top end wear and failures and the rings and liners having less pressure will help increase their longevity too, the same goes for the big ends and mains, which only leaves the ancillary components to go wrong at the normal rate.
■■■■■■■ 220 15 : 1 L12 16 : 1. 
That’s also with a larger bore so actually more strain going through the con rod for less power also produced at higher rpm than the ■■■■■■■■
But we aren’t comparing it’s reliability to the ■■■■■■■■ it was said to be far more reliable than the TL12, so the compression ratio of the ■■■■■■■ is irrelevant.
newmercman:
But we aren’t comparing it’s reliability to the ■■■■■■■■ it was said to be far more reliable than the TL12, so the compression ratio of the ■■■■■■■ is irrelevant.
Were the TL12s an unreliable engine then , i know the build quality of the Marathon like all BL lorries wasn’t up to much but i thought that the TL12 was a good performer obviously that doesnt make it reliable as the V8 proved , i heard from one driver it was a bit of a flier for its time at launch
The 0.680 - 690 was then the same block Daf used in the 2800 - 3600 but with far less power. That tells you something about BL ?
I’ve no idea, my supposition was based on previous posts from anorak cav551 and gingerfold who mentioned the reliability of the L12 as being better than the turbocharged version.
newmercman:
I’ve no idea, my supposition was based on previous posts from anorak cav551 and gingerfold who mentioned the reliability of the L12 as being better than the turbocharged version.
I didn’t say that, and I would trust the other two to know better than me anyway. 
Carryfast:
newmercman:
I think the answer to the L12 being underpowered is more than likely due to it having low compression cylinder packs meant for a turbocharged engine, when a naturally aspirated engine needs higher compression, knowing how BL went about things in those dark times it makes sense. It would also explain their longevity, low compression means lower heat in the top end, so that eliminates a lot of top end wear and failures and the rings and liners having less pressure will help increase their longevity too, the same goes for the big ends and mains, which only leaves the ancillary components to go wrong at the normal rate.■■■■■■■ 220 15 : 1 L12 16 : 1.
L12 vs. Cu220- that’s a good comparison. No one would say that the 220 was bad, nd if the various LEyland engines stack up well against it, then that is a feather in their cap.
“Strain through the con rod” bolleaux.
Where did you get the CRs? They look wrong to me.
newmercman:
But we aren’t comparing it’s reliability to the ■■■■■■■■ it was said to be far more reliable than the TL12, so the compression ratio of the ■■■■■■■ is irrelevant.
Rolls and ■■■■■■■ both comparable NA 12 litre motors ( actually slightly smaller capacity ) both producing a higher specific power output at lower rpm.That was very relevant to Ramone’s question. 
[zb]
anorak:Carryfast:
newmercman:
I think the answer to the L12 being underpowered is more than likely due to it having low compression cylinder packs meant for a turbocharged engine, when a naturally aspirated engine needs higher compression, knowing how BL went about things in those dark times it makes sense. It would also explain their longevity, low compression means lower heat in the top end, so that eliminates a lot of top end wear and failures and the rings and liners having less pressure will help increase their longevity too, the same goes for the big ends and mains, which only leaves the ancillary components to go wrong at the normal rate.■■■■■■■ 220 15 : 1 L12 16 : 1.
L12 vs. Cu220- that’s a good comparison. No one would say that the 220 was bad, nd if the various LEyland engines stack up well against it, then that is a feather in their cap.
“Strain through the con rod” bolleaux.
Where did you get the CRs? They look wrong to me.
If you’ve got more pressure acting on more piston area what else could it be and where can it go according to nmm’s correct assumptions.
That’s the point the L12 ( and TL12 ) don’t stack up well against the ■■■■■■■ or the Rolls and it’s obvious why.
As for CR I just went searching for the respective numbers and that’s what came up.
Either way by definition there can only be more cylinder pressure within the L12/TL12 to get the euivalent, more like less, effort at the crank v the ■■■■■■■ and Rolls.Unless you want to ignore the rules of leverage.
newmercman:
But we aren’t comparing it’s reliability to the ■■■■■■■■ it was said to be far more reliable than the TL12, so the compression ratio of the ■■■■■■■ is irrelevant.
Reliability of the TL12 was never an issue, I think that you have mis-understood the previous post. Many seasoned Leyland operators reckon that the TL12 was the best and most reliable Leyland badged engine since the O.600. Pat Kennet also thought the same about it. The L12 also was reliable.