Carryfast:
Not just acceleration it’s also deceleration…
Imagine this being said by Farmer Michael off YouTube.
Carryfast:
.Oh and all those forces also actually result from the shove put into the flywheel …
Carryfast:
So remind us why are the big end fastenings not as strong as the main bearing and head fastenings ?.
Do you know what the strength of the bolts is, in those three applications?
Carryfast:
Why does distance supposedly not matter to the force equation by reducing the compressive load required to be applied to the piston/con rod assembly for a given specific torque output and resulting tensile load on the head fastening ?.
You could insert any component or quantity into any of the positions in that sentence, and it would not make less sense.
How come the Jap crap are still with us but the original Rover and Triumph aren`t . By the way i never have and never will buy a Japanese car
Carryfast:
newmercman:
Yes you’re right, I had that arse about face, tensile strength is pulling not pushing. So then am I on the right track to think that the greatest tensile load is the point where exhaust changes to intake at TDC? The fractions of a second between the closing of the exhaust valve and the opening of the intake valve will create a vacuum as the piston is pulled down by the rotation of the crankshaft, so the time between TDC and the intake valve fully opening is the answer, or not lol‘Common sense’ says that its the period between exhaust and inlet strokes at max rpm, which also involves massive deceleration, reversal and acceleration, is when the big end fastenings are under the most tension and so long as they hold those tensile loads pass onto the con rod.
Just comparing those fastenings with the head and main bearing fastenings shows that those tensile loads never match the compressive loads resulting from the power stroke.
All the stresses in the piston and rod assembly during the power stroke result from and are proportional to the compressive forces involved in turning the cylinder into a similar environment as gun barrel when it’s fired and the piston/rod assembly is the bullet/shell.
It’s obvious that the more multiplication that can be provided by leverage at the crankshaft then the less those forces applied to the ‘shell’ need to be for an equivalent effort at the crankshaft/flywheel.
Which means less compressive load on the piston/rod assembly and head fastenings for a given output and which matters when we’re going for 100 lb/ft + per litre.Also bearing in mind that 280 hp at 1,800 rpm ( or 400 hp at 1,900 rpm ) actually means less piston speed with a 152 mm stroke than 280 hp at 2,200 rpm with a 142 mm stroke.So even Anorak’s piston speed bollox is moot.
While as I said if AEC had designed the Merlin, with the same stroke as their V8, or the 760, we’d all now be speaking German.No doubt Stokes would still have got the blame.
But AEC designed the Matador that had the accolade as the best medium weight gun tractor in any WW2 army, and their other products produced in WW2 had a very distinguished record. I remember you writing that you drove the council Matador, not the easiest of machines to drive I’ll grant you, but it was probably, what, 35 years old then?
[zb]
anorak:Carryfast:
Not just acceleration it’s also deceleration…Imagine this being said by Farmer Michael off YouTube.
You seem to be arguing with and contradicting yourself.
So tell us what does the piston/rod assembly have to do before reaching TDC on the Exhaust stroke so that it can reverse for the inlet stroke at which point it then accelerates again under tension being pulled back down.Which components are all that’s acting as the brake and then reversing it’s travel dragging it back down.Here’s a clue it’s not the crankshaft but if the big end bearing cap fastenings let go at that point it’s really going to spoil your day because the Piston is either going to keep on going into the head if it’s before TDC or it’s going to be left behind if it happpens after TDC.
IE it’s a reciprocating force acting on the con rod not exactly a centrifugal one.The crankshaft is going around in circles the pistons are only going up and down connected to it.
TDC between the Exhaust Stroke and Inlet stroke at max engine speed is the point when the piston and rod assembly can’t possibly be under more tensile load.That load doesn’t even get close to the compressive load and resulting forces acting on it during the power stroke.
Which is obvious because all the force contained in the flywheel had to be put there first by the power stroke.
A longer stroke acts as a force multiplier in that regard.Trying to put an engine with less of that multiplier up against one with more of it is only going to end one way if we want to maximise and match, let alone beat, their respective specific torque outputs.Or for that matter find some free power to reduce fuel consumption as a bonus.
[zb]
anorak:Carryfast:
Not just acceleration it’s also deceleration…Imagine this being said by Farmer Michael off YouTube.
You seem to be arguing with and contradicting yourself.
So tell us what does the piston/rod assembly have to do before reaching TDC on the Exhaust stroke so that it can reverse for the inlet stroke at which point it then accelerates again under tension being pulled back down.Which components are all that’s acting as the brake and then reversing it’s travel dragging it back down.Here’s a clue it’s not the crankshaft but if the big end bearing cap fastenings let go at that point it’s really going to spoil your day because the Piston is either going to keep on going into the head if it’s before TDC or it’s going to be left behind if it happpens after TDC.
IE it’s a reciprocating force acting on the con rod not exactly a centrifugal one.The crankshaft is going around in circles the pistons are only going up and down connected to it.
TDC between the Exhaust Stroke and Inlet stroke at max engine speed is the point when the piston and rod assembly can’t possibly be under more tensile load.That load doesn’t even get close to the compressive load and resulting forces acting on it during the power stroke.
Which is obvious because all the force contained in the flywheel had to be put there first by the power stroke.
A longer stroke acts as a force multiplier in that regard.Trying to put an engine with less of that multiplier up against one with more of it is only going to end one way if we want to maximise and match, let alone beat, their respective specific torque outputs.Or for that matter find some free power to reduce fuel consumption as a bonus.
[zb]
anorak:Carryfast:
[zb]
anorak:
If you haven’t read Edwardes’ book, how can you know what his decisions were? ……
BMC were zb so lets wipe out Rover and Triumph by turning them over to making Hondas.Yeah right.So what was Leyland’s answer to the BMW 3 series and 5 series after that.Remind us who bought up Rover and the Triumph name and made sure it kept Rover a second rate maker of Jap based crap.I agree, the 3 and 5 series were head and shoulders above anything Triumph could knock together, but the SD1 was a strong competitor, surely?
The 528 wouldn’t have got near a developed 3.9 litre V8 engined Triumph saloon while the 525 was beat by the Triumph .The Dolomite was also a better car than 3 series.So what did Edwardes do.
The Triumph had the equivalent better looking three box styling it also had the equivalent IRS but better rack and pinnion steering.
Rover SD1 was ugly with live axle rear end.But still way way better than the full ■■■■■■ Honda based 820.
Meanwhile Triumph was turned into yet another maker of front wheel drive crap just like BMC but designed and made in Japan like the 820. 
So let’s get this right.
Stokes responsible for TL12/Marathon, Rover V8 types including Range Rover, Triumph 2.5 upgrade.Sort of but not quite the SD1 which going by the Triumph 2.5 we can bet he’d have preferred V8 Triumph 4.0 litre uprade.
Markland responsible for Triumph 2000 and AEC 691/760.
Edwardes responsible for TL12 powered T45.
Run down and closure of AEC.
Splitting truck and bus division.
Turning Triumph into another BMC with a Jap flag.Similar in the case of Rover all part of the Jap deal he’d signed Leyland up to.All with obvious foreseeable beneficial results regarding the foreign competion ( DAF, Volvo, BMW ).
[zb]
anorak:Carryfast:
.Oh and all those forces also actually result from the shove put into the flywheel …
What’s the joke unless you’re saying that the force of the starter motor will be enough to tear the motor apart as it turns it over.Where else is the motor geting its motive forces from if not the power stroke.
[zb]
anorak:Carryfast:
So remind us why are the big end fastenings not as strong as the main bearing and head fastenings ?.Do you know what the strength of the bolts is, in those three applications?
Carryfast:
Why does distance supposedly not matter to the force equation by reducing the compressive load required to be applied to the piston/con rod assembly for a given specific torque output and resulting tensile load on the head fastening ?.You could insert any component or quantity into any of the positions in that sentence, and it would not make less sense.
Obviously wouldn’t make any sense at all to someone who thinks that there is a connection between BMEP and tensile load on the conrod and who seriously thinks that big end fastenings have more tensile strength than the main bearing and head fastenings.
Just think what might have been if you’d have taken your thinking to AEC.
Let’s go full ■■■■■■ by using the same strength fastening for the main bearing caps and cylinder head as the big end bearing caps.On the basis that the max tensile load on the big end cap fastenings is the same as the max tensile load on the main bearing and head fastenings.What could possibly go wrong.
ramone:
How come the Jap crap are still with us but the original Rover and Triumph aren`t . By the way i never have and never will buy a Japanese car
How could anyone buy a Rover or Triumph after Edwardes had stopped them making Rover or Triumph cars obviously to the benefit of BMW.You know like proper straight 6 and V8 powered saloons.( BMW are still with us ).
Carryfast:
[zb]
anorak:Carryfast:
Not just acceleration it’s also deceleration…Imagine this being said by Farmer Michael off YouTube.
You seem to be arguing with and contradicting yourself…
I was quoting you.
gingerfold:
Carryfast:
While as I said if AEC had designed the Merlin, with the same stroke as their V8, or the 760, we’d all now be speaking German.No doubt Stokes would still have got the blame.But AEC designed the Matador that had the accolade as the best medium weight gun tractor in any WW2 army, and their other products produced in WW2 had a very distinguished record. I remember you writing that you drove the council Matador, not the easiest of machines to drive I’ll grant you, but it was probably, what, 35 years old then?
We called it Rommell rumoured to have had war service and made it home.It had been used as a forestry tractor and then recovery wagon.It sounded great through its rotten exhaust.Replaced by a 680 powered Foden. 
As a point of interest the A173’s/0853’s stroke was actually more than the 760’s/TL12’s providing a bore stroke ratio of 0.71.I’m guessing not the same designers as the V8 and 760. 
[zb]
anorak:Carryfast:
[zb]
anorak:Carryfast:
Not just acceleration it’s also deceleration…Imagine this being said by Farmer Michael off YouTube.
You seem to be arguing with and contradicting yourself…
I was quoting you.
You’re the one who suddenly changed your tune to agreeing with me that the highest level of tensile load on the piston and rod assembly is at TDC between Exhaust and Induction stroke.
You also said acceleration.
I said acceleration AND deceleration.( Not in that order )
Obviously having to reverse direction from exhaust stroke to induction stroke.So decelerative kinetic load up to the point of reversal followed by inertial load of the piston and crankshaft after it.All that dependent on and transmitted to the big end bearing cap fastenings in tension to hold the piston and rod assembly on the crank shaft.
The tensile loading of the piston and rod assembly can’t possibly ever be greater than the tensile strength of those fastenings.
Carryfast:
ramone:
How come the Jap crap are still with us but the original Rover and Triumph aren`t . By the way i never have and never will buy a Japanese carHow could anyone buy a Rover or Triumph after Edwardes had stopped them making Rover or Triumph cars obviously to the benefit of BMW.You know like proper straight 6 and V8 powered saloons.( BMW are still with us ).
This mirrors the commercial vehicle side , but the car side is where the money was being pumped to . Poor replacements for previous models , but badging Hondas as Triumphs wasn`t ideal ,then again where was the money coming from to develop new models . The world was changing and the 6 and certainly V8 engine cars were never going to save Rover . Fuel prices were rising and buyers wanted more economical choices. Again i will say i will never buy a Japanese car but the Hondas are one of the most reliable vehicles out there.
ramone:
Carryfast:
This mirrors the commercial vehicle side , but the car side is where the money was being pumped to . Poor replacements for previous models , but badging Hondas as Triumphs wasn`t ideal ,then again where was the money coming from to develop new models . The world was changing and the 6 and certainly V8 engine cars were never going to save Rover . Fuel prices were rising and buyers wanted more economical choices. Again i will say i will never buy a Japanese car but the Hondas are one of the most reliable vehicles out there.
Let’s get this right.
The premium JRT division was actually profitable.It says so in the Ryder report.
BMC was the basket case you know having gone from making cars like the 3 litre Westminster to the Allegro.No surprise there.
Edwardes didn’t need to spend any money to put the already there V8 Rover into the already there Mk2 Triumph 2.5 which Stokes had given him to use for tools in both cases.
So buyers didn’t want three box styled 6 cylinder or V8 saloons.
Remind me how and why did BMW base a successful business plan on exactly that formula in the case of 325, 525, 528, 535, M5, 540 etc etc from 1977.You know the year that Stokes retired from his non influential job of 2 years previously.
You know exactly the same business plan that Stokes was following for Rover and Triumph since the 1960’s.
youtube.com/watch?v=vsfc8IRw5Y4
That’s Stokes’ legacy that he left us and should be remembered for right there if Edwardes had wanted to run with it.A BMW 540 competitor long before BMW had even got to the stage of its Nikasil cylinder nightmare.
Which leaves the question of TL12 Marathon v 305 Rolls Crusader and what might have been if the Roadtrain had been launched with 320 Rolls and 13 speed Fuller to honour him instead of scapegoating him. 
Carryfast:
…You also said acceleration.
I said acceleration AND deceleration.( Not in that order )
…
Don’t they cancel out, to leave a serene state in which velocity does not change?
Disc valves is the way to go………………………………
[zb]
anorak:Carryfast:
…You also said acceleration.
I said acceleration AND deceleration.( Not in that order )
…Don’t they cancel out, to leave a serene state in which velocity does not change?
No it’s deffo like somehow throwing your car instantly into reverse without wearing a seat belt or in this case the big end cap fastenings doing the job of the seat belt.
The question is when you exaggerate the effects of that by trying to pretend that 1,800 rpm with a 152 mm stroke isn’t actually doing that at a lower speed than 2,200 rpm with a 142 mm stroke.Or that reciprocating forces even matter at such speeds.
So you’ve also lost your argument at both ends.142 mm stroke at 2,200 RPM means higher piston speed to obtain the equivalent horsepower than 152 mm stroke at 1,800 rpm.The longer stroke also means more leverage at the power stroke so less compressive load on the piston and rod assembly and the cylinder head fastenings/seal for the equivalent torque output.Also less fuel consumption because distance costs nothing to create but more shove does.
Good luck with the 100 lb/ft per litre 400 hp TL 12.
Retired Old ■■■■:
Disc valves is the way to go………………………………
We’ve got as much forced induction as we want more than enough to blow the motor apart spectacularly.
Filling our cylinders with enough charge isn’t an issue.