Ever since i have started driving trucks one thing i have noticed is how similar spec trucks perform differently,for example you can have two identical spec trucks with same engine power rating,gearbox and drive axle ratio and have similar mileages yet one can pull like a train and give good fuel figures yet another can be a total plug.
I have driven scania v8’s in the past which dont perform like v8’s yet my last truck a man tga 430 with little 10.5 litre engine would at times pass larger engined 460 &480 bhp motors on hills when fully freighted.
Why do engines vary so much performance wise-does it depend on the way they are run in when new,does it all depend on how they are put together in the factory on day of manufacture?
Some people reckon that a vehicle that runs at maximum weight all or most of the time beds in quicker and gives better performance- what do you guys think?
I agree, my 460 ‘59’ plate XF pulls much better than a few of the ‘10’ plate 460 XF’s we have.
I havent got a clue why, suppose I should be grateful mine pulls best 
could be the way they have been run in, many years ago, myself and a friend had identical vans, both brand new straight from the dealer, carried identical kit, he ran his van in properly, i thrashed mine to within an inch of going bang, after a while, we had a race back to Somercotes from Doncaster (own private race track, obviously 
), the result was, he could not keep up with me 
the only difference between the two vans was the way they had been run in
We got all MAN 440,s and they do behave differently, some seem to change down a gear where another one will not also im convinced our newer units dont pull as good as our older ones 
I believe that too, they are designed to be worked hard, from day one. When the very first 44t intermodal trucks were allowed between designated rail terminals and the channel tunnel.
I was driving a 403 MAN, this would have been about 1996 and it wasn’t until 2001 that 44t were allowed on the roads unrestricted. It was during these times that the heavy haulage trucks started to appear to get even more weight on the railway system.
These were ballasted tractors with a converter dolly, pulling a stepframe skelly with an isotank on them. They were used mainly around the chemical plants around Middlesbrough to Teesport. Occasionally the system could be abused, the heavy haulage tractor took the tank into the plant, loaded it to about 50 tonne gross and then swapped trailers outside with a standard 6x2 unit.
These MAN lorries literally pulled like trains from day one, with gross weights closer to 46 tonne than 44 
The paperwork was 100% correct, we were on an intermodal journey, no one said you had to use the closest rail terminal 
However I digress, the trucks were run at these weights from day one and were far superior to most other trucks still running at 38t and they were good on fuel too.
I remember talking to a scania fitter once about this subject,he said operators would sometimes complain about larger v8’s not performing properly-he reckoned some of them were not running at max weight often enough which meant the engine didnt reach a proper performance plateau,he said the only way to cure it would be to put the truck on intensive work running at maximum weight most of the time.
Ive also noticed this my 56 plate 420 scanny is always at max weight or slightly above (whoops) and still seems to out pull newer 460’s and 480’s. but yet my mate drives the same truck for the same firm and his couldn’t pull the ■■■■ off a jelly baby
the 460 cf i have seems to pull quite well but from the day it went on road it has full wieght on it and is permanetly hammered but it will go bang before it gets to 100k’s no doubt.
joedwyer1:
Ive also noticed this my 56 plate 420 scanny is always at max weight or slightly above (whoops) and still seems to out pull newer 460’s and 480’s. but yet my mate drives the same truck for the same firm and his couldn’t pull the ■■■■ off a jelly baby
It’s because of run-in. However precise today’s manufacturing is, parts still need time to bed in, in engine, gearbox, axles… Hence a brand new truck won’t pull as well as a run-in one and shouldn’t work it hard from day 1, it is not “designed for that”, whatever they told you in sales room or garage. If you, you’re more likely to break/scuff something somewhere, if you don’t it’ll run in earlier, but will also wear off earlier.
HomoFaber:
It’s because of run-in. However precise today’s manufacturing is, parts still need time to bed in, in engine, gearbox, axles… Hence a brand new truck won’t pull as well as a run-in one and shouldn’t work it hard from day 1, it is not “designed for that”, whatever they told you in sales room or garage. If you, you’re more likely to break/scuff something somewhere, if you don’t it’ll run in earlier, but will also wear off earlier.
Can anyone translate please?
Rob K:
HomoFaber:
It’s because of run-in. However precise today’s manufacturing is, parts still need time to bed in, in engine, gearbox, axles… Hence a brand new truck won’t pull as well as a run-in one and shouldn’t work it hard from day 1, it is not “designed for that”, whatever they told you in sales room or garage. If you, you’re more likely to break/scuff something somewhere, if you don’t it’ll run in earlier, but will also wear off earlier.
hammer the fxxk out of it from the moment to drive it off the forecourt, it’ll last longer
Read an article about motorbike engines running in, and the most telling time of this process is in the first 20/30 miles when it should be put under load through the rev range to achive a better seal between piston rings and bores for better compression. So in most cases the most telling part of the run in process happens before you even get your new vehicle.
NB12:
Read an article about motorbike engines running in, and the most telling time of this process is in the first 20/30 miles when it should be put under load through the rev range to achive a better seal between piston rings and bores for better compression. So in most cases the most telling part of the run in process happens before you even get your new vehicle.
That is my take on it, when Scanias were imported into Killingholme and delivered on trade plates, many operators complained about the way the lorries had been driven as they would find used cards in the head.
A racing engine may spend time on a dyno, then out on the race track. Think how an engine works in a truck. 1500 revs per minute for 10 minutes = 15000 revolutions. The pistons have done a full cycle (up & down) 15000 times, the camshaft has turned 7500 times, so 50 / 100 miles down the road and any small manufacturing irregularities have gone.
You will do more harm letting a lorry idle, or doing stop / start chip shop runs on its first day out then you will putting 29 tonne of steel on it over the Pennines.
Modern long drain oils, specialist materials & precise engineering can cope with this. It is a simplistic view, but arguments have raged for many years about how a wet nursed lorry from day one will never be as good as one that was worked reasonably hard.
That doesn’t mean screaming up to road junctions and driving like a prat, bearings, brakes, axles, gearboxes & possibly even tyres will need to be bedded in. An engine has to get up to operating temperature to run efficiently, gone are the days where drivers sit in the yard for 20 minutes with their foot on the loud pedal building up the air. Start it up, as soon as the air is up, drive off, let the workload warm the engine.
Even doing this, fuel consumption will start to improve and it will use less engine oil as it reaches 75 / 100,000km
Have heard there is a company around elland/halifax way feather diesels that are brilliant at diagnosing fuel injection problems on trucks-has anyone had any dealings with them?
Also why do truck engines sometimes perform better running at night time with a fine mist in the air than they do during daytime?
CALUM:
Have heard there is a company around elland/halifax way feather diesels that are brilliant at diagnosing fuel injection problems on trucks-has anyone had any dealings with them?
Also why do truck engines sometimes perform better running at night time with a fine mist in the air than they do during daytime?
Not just truck engines. When I was younger I always thought my bikes ran that little bit sweeter in those kind of conditions.
CALUM:
Have heard there is a company around elland/halifax way feather diesels that are brilliant at diagnosing fuel injection problems on trucks-has anyone had any dealings with them?
Also why do truck engines sometimes perform better running at night time with a fine mist in the air than they do during daytime?
Because the air is denser. Denser air = better performance.
Cold air is better for turbo performance. Speak to any Subaru owners.
All of our Scanias have the 420 engine, mines an 05 and is one of the slowest on the flat, the 07s and 09s fly by until we get to an incline, then i just storm back past them It had a new Turbo and intercooler last year and feels stronger compared to the other 05s.
The 07 and 09 plates have different gearing for economy, in top they run at 1100rpm whereas the 05s run at 1400rpm. Problem is running close to 44 ton you have to work em harder on the hills, theyre changing down whereas i can hold it in a higher gear for longer.