The Carryfast engine design discussion

UK PROFESSIONAL DRIVERS FORUMS OLD TIME LORRIES, COMPANIES AND DRIVERS (INTERACT
601

dave docwra:

newmercman:
Front wheel drive a mistake? Really? Are you on crack? Is every car manufacturer in the world with the exception of BMW wrong? Seriously mate that one statement is the most ridiculous one you have ever made and there’s quite a few to choose from…

I think the BMW 1 series is Front Wheel Drive.

The current version 1, 2, X1 & X2 are all front wheel drive, based on a streched Mini platform. The interesting thing is why BMW relented and changed to front wheel drive after resisting for so long. There had been an on going internal argument about whether to change between bean counters and engineers, so the bean counters asked existing customers of the then rear drive 1 series if they thought their car was fwd or rwd, when 70% said that they thought it was already fwd the engineers had lost the argument.

Mercedes of course has used fwd for it’s small cars since the first A class came out.

602

acd1202:
The current version 1, 2, X1 & X2 are all front wheel drive, based on a streched Mini platform. The interesting thing is why BMW relented and changed to front wheel drive after resisting for so long. There had been an on going internal argument about whether to change between bean counters and engineers, so the bean counters asked existing customers of the then rear drive 1 series if they thought their car was fwd or rwd, when 70% said that they thought it was already fwd the engineers had lost the argument.

Mercedes of course has used fwd for it’s small cars since the first A class came out.

Notice the engineers didn’t ‘ask’ the supposed ‘customers’.Sort of a conflict of interest there. :wink:
Meanwhile in the real world.They’ll probably listen to the engineers in the case of 3 and 5 series if they’ve got any sense. :laughing:

carsalesbase.com/europe-bmw-1-series/

603

[zb]
anorak:
This is analogous to the load on the big end caused by its centrifugal acceleration, multiplied by the mass of the rod and piston. No point trying to get our mate to stop and think about it- when faced with such a challenge

There you go Anorak.

145 mm bore so a reasonably big heavy piston and rod.

183 mm stroke.

Somehow as if by magic it all stays together at 2,300 rpm. :wink:
cat.com/en_GB/products/new/p … 94378.html

604

Edit to add so the C18 stays together at 2,300 rpm unlike the TL12 would boosted to 166 lb/ft per litre at 1,600 rpm. :unamused:

605

Carryfast:

dazcapri:

dave docwra:
I think the BMW 1 series is Front Wheel Drive.

Yeah and most of the BMW built Mini’s

Yep impossible to compete in that market sector doing the job the right way when everyone else is doing it the cheap way. :unamused:
What could possibly go wrong.
Now see if they dare to do it with the 3 and 5 series.

So BL were years ahead of your beloved BMW because they knew that in the 50’s

606

I had the pleasure of operating a Wirtgen road milling machine last week, I had to drive it around the dock and up onto my trailer and then offload it and park it at the other end, it had a C18 rated at 735hp, oh it made a lovely noise, almost like the burble of a big V8.

I believe the C18 crankcase is the same as the C15, it has a longer stroke and bigger bore, very short pistons and a different head to get the extra cubic capacity. Is the bore/stroke ratio the same as the 15.2l C15?

It is accepted that the 3406E models 1LW through to 5EK and the C-15 6NZ 14.6l were the best road engines CAT produced, yet for the C15 ACERT BXS, MXS, NXS and SDP they went to 15.2l by adopting the C16 7CZ crankshaft and yet they all were rated at 475hp to 550hp with 1850 or 2050 lbs/ft. Australia got a 600/625hp 3406E and C-15 6NZ with 2050 lbs/ft and everyone got that option with the bigger ACERT models, my question is why the increase in size with no increase in power or torque? It wasn’t reliability, so why?

607

In many years of being around AEC engines from the AV470, AV505, AV760, TL12, L12, I never had any put a con rod through the crank case. No doubt it did happen with an occasional high mileage engine with wear at the bottom end, or simply metal fatigue in the con rod. It can happen with any make of engine. In more recent times I have had a MAN throw a con rod through the crankcase, and in the last three years two Mercedes Actros at my depot have thrown con rods out. In mitigation both had done about 1 million kms. Similarly the traditional Leyland engines never did it. We had a Leyland Super Comet with an O.400 that ran at 5lbs / square inch oil pressure hot, but it kept going. So once again CF needs to provide factual evidence that the AEC engine design caused regular bottom end failures… I don’t know of any such evidence.

608

Carryfast:
Edit to add so the C18 stays together at 2,300 rpm unlike the TL12 would boosted to 166 lb/ft per litre at 1,600 rpm. :unamused:

How do you know you are only guessing

609

dazcapri:

Carryfast:
Yep impossible to compete in that market sector doing the job the right way when everyone else is doing it the cheap way. :unamused:
What could possibly go wrong.
Now see if they dare to do it with the 3 and 5 series.

So BL were years ahead of your beloved BMW because they knew that in the 50’s

Let’s get this right BMW have no option than to join in with the race to the bottom.
They are obviously limiting their exposure to it where possible.( No fwd 3 and 5 series so far ).
Did you actually check out the sales figures for rwd 1 series v fwd.
Seems to follow the same pattern of what happened to firstly BMC then Triumph and Rover and Ford and GM after making the same change.BMC obviously knew that in the 1960’s.
Read all the comments few actually welcome the change to fwd but plenty moaning about it.I didn’t need to bother putting adding to their objections.
youtube.com/watch?v=iwbiev8xCTY

610

gingerfold:
In many years of being around AEC engines from the AV470, AV505, AV760, TL12, L12, I never had any put a con rod through the crank case. No doubt it did happen with an occasional high mileage engine with wear at the bottom end, or simply metal fatigue in the con rod. It can happen with any make of engine. In more recent times I have had a MAN throw a con rod through the crankcase, and in the last three years two Mercedes Actros at my depot have thrown con rods out. In mitigation both had done about 1 million kms. Similarly the traditional Leyland engines never did it. We had a Leyland Super Comet with an O.400 that ran at 5lbs / square inch oil pressure hot, but it kept going. So once again CF needs to provide factual evidence that the AEC engine design caused regular bottom end failures… I don’t know of any such evidence.

He’s now comparing a 12.5l engine with one nearly half as big again… 18 litres Quote CF: "Edit to add so the C18 stays together at 2,300 rpm unlike the TL12 would boosted to 166 lb/ft per litre at 1,600 rpm"

Specific torque = Torque/ Capacity… Therefore Torque = Specific torque x Capacity… 166 x 12.47 =2070 lbft

BHP = Torque x rpm/5252… Therefore Torque = bhp x 5252/rpm…2070x1600/5252 = 630 BHP …and 2070x5252/2300 = 906 bhp

So who makes a sub 13 litre 630 bhp engine let alone a sub 13 litre 900bhp engine?

The C18 is capable of 1136 bhp and 2594lbft @ 2300rpm … and 3011lbft and 917 bhp @1600rpm… 3011/18.1 = 166 lbft/Litre Specific Torque

s7d2.scene7.com/is/content/Cater … EHM0004-00

Edit add: FPT Iveco have not released their 850bhp Cursor 16 for automotive use even though its external dimensions are very close to the Cursor 13, because they do not consider that current forward control cabs and chassis provide enough space to meet its cooling requirements.

611

newmercman:
I had the pleasure of operating a Wirtgen road milling machine last week, I had to drive it around the dock and up onto my trailer and then offload it and park it at the other end, it had a C18 rated at 735hp, oh it made a lovely noise, almost like the burble of a big V8.

I believe the C18 crankcase is the same as the C15, it has a longer stroke and bigger bore, very short pistons and a different head to get the extra cubic capacity. Is the bore/stroke ratio the same as the 15.2l C15?

It is accepted that the 3406E models 1LW through to 5EK and the C-15 6NZ 14.6l were the best road engines CAT produced, yet for the C15 ACERT BXS, MXS, NXS and SDP they went to 15.2l by adopting the C16 7CZ crankshaft and yet they all were rated at 475hp to 550hp with 1850 or 2050 lbs/ft. Australia got a 600/625hp 3406E and C-15 6NZ with 2050 lbs/ft and everyone got that option with the bigger ACERT models, my question is why the increase in size with no increase in power or torque? It wasn’t reliability, so why?

The bore stroke ratios for C15 and C18 are .80 and .79 respectively.The 3406 was 0.83.

As you suggested yourself CAT outputs seem to be conservatively if not under stated ?.

Or going by the figures at face value their engines seem to be deliberately under stressed going back to 3406E 126 lbft per litre v ■■■■■■■ N14 132 lbft per litre for example.

But all the following progressions to C15 to C18 seem to provide an increase over the 3406 E regarding specific torque to whatever degree.
A massive leap in the case of the C18 at 166 lbft per litre which seems to reflect the jump from the 3406 165 mm stroke to 183 mm.

My view is that there is no doubt leverage matters but there are exceptions like the IVECO motor proving rules.The stresses needing to be contained in that thing must be massive.More than I think AEC could ever have dealt with in the day to match the RR and why would they have needed to.

I think if AEC had used the 590’s 0.84 bore stroke ‘ratio’, as opposed to its stroke, for the TL12 history might have been different.

While I don’t think the IVECO motors will be displacing the MX11 or MX 13 let alone CAT on any shopping lists.

612

Carryfast:

[zb]
anorak:
This is analogous to the load on the big end caused by its centrifugal acceleration, multiplied by the mass of the rod and piston. No point trying to get our mate to stop and think about it- when faced with such a challenge

There you go Anorak.

145 mm bore so a reasonably big heavy piston and rod.

183 mm stroke.

Somehow as if by magic it all stays together at 2,300 rpm. :wink:
cat.com/en_GB/products/new/p … 94378.html

There you go again. I did not say half of that which appears within quotes. You’re arguing with yourself. Remove my name from the wrong quotes, please.

613

gingerfold:
In many years of being around AEC engines from the AV470, AV505, AV760, TL12, L12, I never had any put a con rod through the crank case. No doubt it did happen with an occasional high mileage engine with wear at the bottom end, or simply metal fatigue in the con rod. It can happen with any make of engine. In more recent times I have had a MAN throw a con rod through the crankcase, and in the last three years two Mercedes Actros at my depot have thrown con rods out. In mitigation both had done about 1 million kms. Similarly the traditional Leyland engines never did it. We had a Leyland Super Comet with an O.400 that ran at 5lbs / square inch oil pressure hot, but it kept going. So once again CF needs to provide factual evidence that the AEC engine design caused regular bottom end failures… I don’t know of any such evidence.

I didn’t ever say they did.
What I did say is that the limitations of the 142 mm stroke and resulting deficit in leverage would have proven to be insurmountable at 100 lbft per litre outputs.You know like foreseeably required for the new T45.

614

cav551:

gingerfold:
In many years of being around AEC engines from the AV470, AV505, AV760, TL12, L12, I never had any put a con rod through the crank case. No doubt it did happen with an occasional high mileage engine with wear at the bottom end, or simply metal fatigue in the con rod. It can happen with any make of engine. In more recent times I have had a MAN throw a con rod through the crankcase, and in the last three years two Mercedes Actros at my depot have thrown con rods out. In mitigation both had done about 1 million kms. Similarly the traditional Leyland engines never did it. We had a Leyland Super Comet with an O.400 that ran at 5lbs / square inch oil pressure hot, but it kept going. So once again CF needs to provide factual evidence that the AEC engine design caused regular bottom end failures… I don’t know of any such evidence.

He’s now comparing a 12.5l engine with one nearly half as big again… 18 litres Quote CF: "Edit to add so the C18 stays together at 2,300 rpm unlike the TL12 would boosted to 166 lb/ft per litre at 1,600 rpm"

Specific torque = Torque/ Capacity… Therefore Torque = Specific torque x Capacity… 166 x 12.47 =2070 lbft

BHP = Torque x rpm/5252… Therefore Torque = bhp x 5252/rpm…2070x1600/5252 = 630 BHP …and 2070x5252/2300 = 906 bhp

So who makes a sub 13 litre 630 bhp engine let alone a sub 13 litre 900bhp engine?

The C18 is capable of 1136 bhp and 2594lbft @ 2300rpm … and 3011lbft and 917 bhp @1600rpm… 3011/18.1 = 166 lbft/Litre Specific Torque

s7d2.scene7.com/is/content/Cater … EHM0004-00

Edit add: FPT Iveco have not released their 850bhp Cursor 16 for automotive use even though its external dimensions are very close to the Cursor 13, because they do not consider that current forward control cabs and chassis provide enough space to meet its cooling requirements.

The point was the connection between the C18’s specific torque output and its leverage.Also the point that if a 183 mm stroke can stay together at 2,300 rpm what is Anorak’s problem with 154 mm let alone 152 mm staying together at 1,900 rpm.That was all.
So the Cursor 16 has a bore stroke ratio of 0.83.Your point being what.

615

Carryfast:

dazcapri:

Carryfast:
Yep impossible to compete in that market sector doing the job the right way when everyone else is doing it the cheap way. :unamused:
What could possibly go wrong.
Now see if they dare to do it with the 3 and 5 series.

So BL were years ahead of your beloved BMW because they knew that in the 50’s

Let’s get this right BMW have no option than to join in with the race to the bottom.
They are obviously limiting their exposure to it where possible.( No fwd 3 and 5 series so far ).
Did you actually check out the sales figures for rwd 1 series v fwd.
Seems to follow the same pattern of what happened to firstly BMC then Triumph and Rover and Ford and GM after making the same change.BMC obviously knew that in the 1960’s.
Read all the comments few actually welcome the change to fwd but plenty moaning about it.I didn’t need to bother putting adding to their objections.
youtube.com/watch?v=iwbiev8xCTY

They are all were moaning about the styling. None of them give a monkey’s about the mechanicals. It’s irrelevant anyway- the cars are designed to provide safe, comfortable transport. Even the greatest sports saloons, like the RWD ■■■■■■, needed a 5-link rear end, LSDs and uprated springs/dampers, to make them satisfying to drive. The only family car to reward sporting skills behind the wheel, without resorting to modifications, was the Mini.

616

Carryfast:
The point was the connection between the C18’s specific torque output and its leverage.Also the point that if a 183 mm stroke can stay together at 2,300 rpm what is Anorak’s problem with 154 mm let alone 152 mm staying together at 1,900 rpm.That was all.
So the Cursor 16 has a bore stroke ratio of 0.83.Your point being what.

Where do I have a “problem” with an engine running at 1900rpm?

This is becoming stupid.

Tell me the bore, stroke and peak RPM of the two engines you seem to be comparing- then I might be able to comment.

617

I’ll answer the CAT question I asked myself then as everyone is transfixed on con rods, it was the same reason ■■■■■■■ went to 15l and Detroit to 14l, heat transfer. ACERT and EGR produced much higher combination temperature and the increased swept volume allowed more surface area to disperse that heat, so you see there’s a practical reason that stroke was increased, it wasn’t to make hot rods.

618

Carryfast:

dazcapri:

Carryfast:
Yep impossible to compete in that market sector doing the job the right way when everyone else is doing it the cheap way. :unamused:
What could possibly go wrong.
Now see if they dare to do it with the 3 and 5 series.

So BL were years ahead of your beloved BMW because they knew that in the 50’s

Let’s get this right BMW have no option than to join in with the race to the bottom.
They are obviously limiting their exposure to it where possible.( No fwd 3 and 5 series so far ).
Did you actually check out the sales figures for rwd 1 series v fwd.
Seems to follow the same pattern of what happened to firstly BMC then Triumph and Rover and Ford and GM after making the same change.BMC obviously knew that in the 1960’s.
Read all the comments few actually welcome the change to fwd but plenty moaning about it.I didn’t need to bother putting adding to their objections.
youtube.com/watch?v=iwbiev8xCTY

Could you explain why for a small to medium family car RWD would be and advantage over FWD? Not looking at performance cars, just bread and butter. I would say the BMC group were ahead of the game but suffered multiple issues no fault of the base design per se.

619

newmercman:
I’ll answer the CAT question I asked myself then as everyone is transfixed on con rods, it was the same reason ■■■■■■■ went to 15l and Detroit to 14l, heat transfer. ACERT and EGR produced much higher combination temperature and the increased swept volume allowed more surface area to disperse that heat, so you see there’s a practical reason that stroke was increased, it wasn’t to make hot rods.

What about heat transfer through the piston? Surely that would have increased the temperature of the rods?

Coat duly donned, door approached. :laughing:

620

How did Rolls Royce reduce con rod stress in the Merlin engine? To prevent a lot of frantic googling, as I’ve just read the book I’ll answer my own question. They designed a forked end (no not a mis-spelling :confused: ) at the gudgeon pin end.