Bri963
Well-known member
You don’t need to. Reciprocating forces in a 5 at 72 degree intervals, on a 4 at 180 degrees - 1 & 4 directly opposite 2 & 3.
S
Smiffy
Well-known member
People like this have always and will always exist and tbh they aren't the problem. It's the fact the industry has positioned it as a dumping ground for them. In a somewhat sensible culture we wouldn't train them, we simply wouldn't allow them near machinery
kabin man
Well-known member
Lancs Lad
Well-known member
Do you reckon the machinery actually sorts them out in flip flop land?
Grow wise or become part of the smelter kind of thing?
V8Druid
do it as well as you can,but learn to do it better
probably got many times more common sense than your average droid here
S
Smiffy
Well-known member
Either the machinery removes them from the gene pool or the knuckle draggers are weeded out and sent to fold raph laren and abbibas tshirts in a sweat shop, whilst the slightly more intelligent are allowed to operate 3/4's of a digger
Lancs Lad
Well-known member
High time the gene pool had a cleanse here...
Was thinking this bulldog saga...the chain wearing tracksuit swaggering smackhead brigade that own them should be put down as well. Or let the dogs sort them out natural selection style.
Gecko
Well-known member
IL 4's are easy, you can "see" it is balanced, but there are two common firing orders for IL4's (1,3,4,2 being the most common, but 1,3,2,4 cools better when you have siamese ports). The vibrations setup by the diferent firing orders are not the same.
Simply saying a 5cyl has evenly spaced 72° crank intervals (or a six having 60° intervals) only tells you it should be statically balanced (also known as 'primary balance'). Trouble is, that is just a 2D concept and doesn't take into account where the masses are along the length of the crankshaft. This is the "dynamic' (or secondary) balance and requires either a lot of maths or actually spinning it up on a balance rig.
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Bri963
Well-known member
You can statically balance any engine, whether it’s one or twenty four cylinders. That isn’t the biggest problem. Once rotating a four cylinder has its offset mass just past TDC and just past BDC when combustion occurs which causes vertical forces which need to be balanced out. Easier with common rail and multi-point injection, but some mechanical counterbalancing is still required. I know myself from seeing 25 years of evolution of our fours that the mass required has been greatly reduced. However, look at a five cyl crank and you’ve never got two crank pins diametrically opposed to each other. The the distribution of mass axially is a red herring, that only has consequences for the required rigidity of the crank and every engine has a flywheel which is essentially an axially offset mass. The fact that manufacturers are dropping 5’s is down to manufacturing expenses vs limited benefits over a 4 due to improved combustion technology.
(PS, usual firing orders for a four are 1-3-4-2 and 1-2-4-3, not 1-3-2-4.)
(PS, usual firing orders for a four are 1-3-4-2 and 1-2-4-3, not 1-3-2-4.)
B
bobthebuilder
Well-known member
Thats a bit much for me on a sunday morning
JerryRtilt
Well-known member
Bit much for me any morning
JerryRtilt
Well-known member
Anyway enough about Balance, would it be agreed that a 5 cylinder lump offers a good compromise between the Torque characteristics of a 4 and a 6 ?
Bri963
Well-known member
I think everyone who’s driven or operated something with a 5 would agree.
Sorry chaps, I was starting to bore myself writing that So I do sympathise.
Gecko
Well-known member
you can statically balance an aircraft carrier (they are!)
Going back to basics, take a skinny motorbike wheel - when a tyre shop balances it, the weights are on (or close) to the centerline (sometimes on the spokes). That'll give you a static balance which is good enough because the wheel is narrow.
In this case, the out of balance wheel may be treated as a single point mass at a single radius, resulting in a centrifugal force: F = m ω^2 r
where ω is measured in radians.
The balancing mass and the radius may be quite different to the 'out of balance' mass, but will balance perfectly so long as the equation: m1 ω^2 r1 + m2 ω^2 r2 sums to zero.
When you go to a car-width wheel, weights are put on the inner and outer (usually at different angles) because the greater width means the dynamic component becomes significant.
Going to a multi cylinder crankshaft, you've got multiple masses at different angles on multiple planes
Borrowing from a textbook
I think you'll find that is due to improvements in materials and manufacturing that allow lighter pistons, rods & gudgeons which in turn require lighter balancing mass.
That's quite true, but is also true of every engine with an odd number of cylinders
not at all. out-of-plane imbalance will cause rocking.
It is, but the mass is evenly distributed, so it does not contribute (or compensate) for a radial out-of-balance.
The flywheel absorbs the power spikes and releases the energy more gently to smooth the power delivery
It's engines or church - pick one
6
6feetdown
Well-known member
Church was looking goodyou can statically balance an aircraft carrier (they are!)
Going back to basics, take a skinny motorbike wheel - when a tyre shop balances it, the weights are on (or close) to the centerline (sometimes on the spokes). That'll give you a static balance which is good enough because the wheel is narrow.
In this case, the out of balance wheel may be treated as a single point mass at a single radius, resulting in a centrifugal force: F = m ω^2 r
where ω is measured in radians.
The balancing mass and the radius may be quite different to the 'out of balance' mass, but will balance perfectly so long as the equation: m1 ω^2 r1 + m2 ω^2 r2 sums to zero.
When you go to a car-width wheel, weights are put on the inner and outer (usually at different angles) because the greater width means the dynamic component becomes significant.
Going to a multi cylinder crankshaft, you've got multiple masses at different angles on multiple planes
Borrowing from a textbook
View attachment 51489
I think you'll find that is due to improvements in materials and manufacturing that allow lighter pistons, rods & gudgeons which in turn require lighter balancing mass.
That's quite true, but is also true of every engine with an odd number of cylinders
not at all. out-of-plane imbalance will cause rocking.
It is, but the mass is evenly distributed, so it does not contribute (or compensate) for a radial out-of-balance.
The flywheel absorbs the power spikes and releases the energy more gently to smooth the power delivery
It's engines or church - pick one
Bri963
Well-known member
I did engines, then church. Wish I’d stayed there.
Gecko, whatever the old books say, a 5 is inherently smoother than a 4, and and Far smoother than a three Due to power delivery overlap. I am also aware of balance, firing orders and what a flywheel is for, having worked for an engine manufacturer for 25 years, including 3 in quality and the last 19 in in-machine test. In fact I’m a bit lost what we’re arguing about here.
Gecko, whatever the old books say, a 5 is inherently smoother than a 4, and and Far smoother than a three Due to power delivery overlap. I am also aware of balance, firing orders and what a flywheel is for, having worked for an engine manufacturer for 25 years, including 3 in quality and the last 19 in in-machine test. In fact I’m a bit lost what we’re arguing about here.
Lancs Lad
Well-known member
Your not the only one
But all I know is the 5cyl T5 TDI was damn site better than the 4cyl T6 pile of shite
Bri963
Well-known member
We had a 6 come off test with a hole in the piston, so effectively it was a 5 and that one ran a bit rougher than the 4’s.Your not the only one
But all I know is the 5cyl T5 TDI was damn site better than the 4cyl T6 pile of shite
Bucket on wheels
Well-known member
from 2000 to 2002 I had an Audi S6 2.2 l 5 cylinder it originally had 230 horses Mine was adjusted
a little bit on, so it delivered 330 horses
it pulled smoothly and like only 330 horses can
still to this day There are a couple of Guys in my hometown that does not speak to me because I beat their Bmw in both acceleration and top speed
I do regret selling it but when I was offered 50% more than I give for the car
When I bought it I regrettable sold It
I just loved that engine
a little bit on, so it delivered 330 horses
it pulled smoothly and like only 330 horses can
still to this day There are a couple of Guys in my hometown that does not speak to me because I beat their Bmw in both acceleration and top speed
I do regret selling it but when I was offered 50% more than I give for the car
When I bought it I regrettable sold It
I just loved that engine
JerryRtilt
Well-known member
Would a V8 with two holed pistons be any smoother than a 4 ?
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