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which 4 cylinder firing order is better

02GF74 - 17/3/08 at 03:50 PM

and why?

DarrenW - 17/3/08 at 03:59 PM

I always find the one the car was designed with is best. Why? Cos the other one wont run right.

oily85 - 17/3/08 at 04:12 PM

I think they're just the opposite of each other aren't they

1-3-4-2-(1-3-4-2)-1-3-4-2
1-2-4-3-1-(2-4-3-1)-2-4-3

02GF74 - 17/3/08 at 04:25 PM

^^^ well yeah.

1342 fires the middle cylinder before its outer neighbour whereas 1243 fires outer cylinder before its neighbour.

Mr Whippy - 17/3/08 at 04:26 PM

are you trying to suggest you even have a choice?

02GF74 - 17/3/08 at 04:31 PM

^^^ yes there is a choice. 1342 is used on vast majority of engines with Ford using 1243 in the past.

Porsche use a different order on their flat fours but we'll ignore that since it is not an inline 4.

jollygreengiant - 17/3/08 at 04:49 PM

quote:
Originally posted by DarrenW
I always find the one the car was designed with is best. Why? Cos the other one wont run right.

I was assistant tutor on a motor mech course once and we had this here 'wannabe' lad on the training course. He was topping up the antifreeze on his Senator 3.0litre, one afternoon, when he appeared in the study room and asked me what the firing order was on his car. So I told him to go and look it up in the Auto Data book. He said ' I did but but they haven't got it right so I just go and reconnect the spark plug leads till I have got it right.'

Turned out that whilst topping up the antifreeze he decided that the timing was out, so he adjusted the distributor, then he 'rearranged all the plug leads so that they looked neater. At that point the engine wouldn't start at all. So he decided to go back to basics and refit the leads as per auto data (without any regard for where TDC No1 was in relation to the rotor arm). But it still wouldn't start because of where he had adjusted the distributor to without the engine running. It was at that point that he asked what the firring order was 'because the book was wrong.' Doh

paulf - 17/3/08 at 04:51 PM

Tuned crossflows do sound nice , dont know if its due to the firing order, zetecs are 1342 as most other engines and dont sound the same.
Paul.

Mr Whippy - 17/3/08 at 05:00 PM

quote:
Originally posted by 02GF74
^^^ yes there is a choice. 1342 is used on vast majority of engines with Ford using 1243 in the past.

Porsche use a different order on their flat fours but we'll ignore that since it is not an inline 4.

most folk are stuck with it, unless they like to grind there own cams

Richard Quinn - 17/3/08 at 05:31 PM

Ok, which is better for a 4 cyl boxer - 1,4,3,2 (VW) or 1,3,2,4 (Subaru)?
(I know the answer before anyone takes my head off)

MikeRJ - 17/3/08 at 06:34 PM

quote:
Originally posted by Richard Quinn
Ok, which is better for a 4 cyl boxer - 1,4,3,2 (VW) or 1,3,2,4 (Subaru)?
(I know the answer before anyone takes my head off)

They are the same (well, technically a mirror image I think) as Subaru numbers the cylinders differently

britishtrident - 17/3/08 at 06:41 PM

In effect they are the same --- 6 cylinder firing orders are more complex.

Coose - 17/3/08 at 09:31 PM

quote:
Originally posted by paulf
Tuned crossflows do sound nice , dont know if its due to the firing order, zetecs are 1342 as most other engines and dont sound the same.
Paul.

X-flows are 1342 also, but the sound comes from the fact that they're 8-valve and not 16. The difference is in the fact that you've got 8 big valves clattering against their seats instead of 16!

NS Dev - 17/3/08 at 10:43 PM

well if we are playing silly games, I know of somebody running a 4 cylinder vauxhall race engine with 1&4 - 2&3, as a twin...............

obviously couldn't decide which order was best so removed the debate!!!

get into vee engines and it all gets far to complex and annoying, what with unequal firing angles and all that caboodle!!

[Edited on 17/3/08 by NS Dev]

MikeRJ - 17/3/08 at 10:53 PM

quote:
Originally posted by Coose
X-flows are 1342 also,

The Kent crossflow (and I think Valencia and HCS) has a firing order of 1243.

hemibum - 18/3/08 at 12:32 AM

quote:
Originally posted by MikeRJ

quote:
Originally posted by Coose
X-flows are 1342 also,

The Kent crossflow (and I think Valencia and HCS) has a firing order of 1243.

Twas Lotus I believe who changed the firing order of the Kent engine while developing the Twink?

02GF74 - 18/3/08 at 11:49 AM

quote:
Originally posted by MikeRJ

quote:
Originally posted by Coose
X-flows are 1342 also,

The Kent crossflow (and I think Valencia and HCS) has a firing order of 1243.

yes, crossflow is 1243.

02GF74 - 18/3/08 at 11:50 AM

quote:
Originally posted by NS Dev
well if we are playing silly games, I know of somebody running a 4 cylinder vauxhall race engine with 1&4 - 2&3, as a twin...............

that is wasted spark though.

02GF74 - 18/3/08 at 11:53 AM

I was hoping there was a proper reaosn like one is smoother. less stree on the crank or will run cooler etc. but I just don't see it myself.

Whoever designed the crossflow may have had a good reason for doing this - could be something ridiculous like the igntion leads are shorter than for 1342 so saves 20 p!!???!?!

matt_claydon - 18/3/08 at 12:09 PM

quote:
Originally posted by 02GF74

quote:
Originally posted by NS Dev
well if we are playing silly games, I know of somebody running a 4 cylinder vauxhall race engine with 1&4 - 2&3, as a twin...............

that is wasted spark though.

I think he meant the guy had a custom cam so that the cylinders actually fired simultaneously.

Interesting idea, probably a bit rough at low revs but will actually be better balanced at high revs.

Volvorsport - 18/3/08 at 12:51 PM

big bang theory , 2 cylinders firing at the same time .

of half a nascar v8 in a class 9 .

Coose - 18/3/08 at 01:09 PM

quote:
Originally posted by MikeRJ

quote:
Originally posted by Coose
X-flows are 1342 also,

The Kent crossflow (and I think Valencia and HCS) has a firing order of 1243.

Which is 1342 if you stand at the other end! Therefore, no real difference.....

matt_claydon - 18/3/08 at 01:31 PM

quote:
Originally posted by Coose

quote:
Originally posted by MikeRJ

quote:
Originally posted by Coose
X-flows are 1342 also,

The Kent crossflow (and I think Valencia and HCS) has a firing order of 1243.

Which is 1342 if you stand at the other end! Therefore, no real difference.....

No it's not, standing at the other end makes 1=4, 2=3, 3=2, 4=1 so the firing is 4-3-1-2 which is the same as 1-2-4-3, not the same as 1-3-4-2.

1342 is the same as running 1243 backwards.

[Edited on 18/3/08 by matt_claydon]

britishtrident - 18/3/08 at 04:01 PM

Xflo is 1-2-4-3
Fords were traditionally always 1-2-4-3 going back to the Model T perhaps even earlier.

Lotus-Ford Twincam wasn't a Ford design Chapman paid peanuts to Harry Mundy & Richard Ansdale to design it. JAP assembled it.

http://www.hemmings.com/hmn/stories/2006/10/01/hmn_feature25.html

britishtrident - 18/3/08 at 04:07 PM

quote:
Originally posted by Volvorsport
big bang theory , 2 cylinders firing at the same time .

of half a nascar v8 in a class 9 .

I think the prize must go to those Honda F1 engines Lotus & MacLaren used way back in the Mansell era, in effect they were 2 three cylinder engines sharing a common flat plane crank --- sounding a bit rough didn't quite cover it. First time the bold Nige drove one he came back inwithout completing a lap swearing it was broken.

Coose - 18/3/08 at 04:13 PM

Deleted because I just really can't be bothered any more. No really, I just can't.....

[Edited on 18/3/08 by Coose]

matt_claydon - 18/3/08 at 05:10 PM

To put it another way, look at the animation here: http://www.cybersteering.com/cruise/feature/engine/engine.html

This is a 1243 engine and the firing order is 1243 no matter which end of the engine you call the front. There is no way this pattern can be described as "1342".

Dynamically the two are absolutely identical though (in terms of balanced and unbalanced forces and moments) and there are thereofre no mechanical advantages of one over the other.

Edit: the tables at the bottom of that page show the fundamental difference. A line in the top table eg ICEP does not appear at any point in the bottom table which ever way along the rows you read.

Top table is 1342, bottom is 1243.

[Edited on 18/3/08 by matt_claydon]

t.j. - 18/3/08 at 07:53 PM

The Fiesta or KA sound is always around with 1243. That are really tough engines. So no problem. Maybe for balance, cooling, exhaust you could choose a different firing-order.

But I prefer logical: 1342

thomas4age - 19/3/08 at 05:33 PM

regarding the exhaust an the desing of the primaries and the order in which they enter the collector you'd just need to make sure, that the pulses line up to aid scavenging from the cylinders.
for both firing orders discussed the orderof collector entry is the same, the target is to recieve the exhaust pulses into the collector in an orderly fashion ie 180 degrees appart

when firing order is 1-2-4-3,
cylinder:
1 needs to be next to 4
2 needs to be next to 3
4 needs to be next to 1
3 needs to be next to 2

when you make the same list for the firing order 1-3-4-2.
cylinder
1 needs to be next to 4
3 needs to be next to 2
4 needs to be next to 1
2 needs to be next to 3

You'll get the same list of the only thing is that the 4 ports on the collector fed in reverse order of the first firing order, which is the same thing as phisicly rotating the collector 180 degrees. taking the headers with it (IE twisting it around)
they both end up being 180degrees systems. think of the cylinders as 2 pairs. outer two running 360 appart and the inner 2 also running 360 appart,

in other words the reason for the difference in engine note cannot be this change in firing order. unless the exhaust system is phisicly different in desing.

grtz Thomas

[Edited on 19/3/08 by thomas4age]