Does Changing Firing Order make more Power?

[BLE 'BURBAN]

always remember.... There is no such thing as a stupid question.....
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.only UNINQUISITIVE IDIOTS!!!!

[xrcr]

You can't fix stupid. Dumb on the other hand is teachable. That's what I figured this forum was for.

[camshaftgsxr]

Originally Posted by 406 Q-ship

The 4/7 swap does not make the engine smoother, that was done by racers to get rid of the 5 and 7 firing so close together.

which makes it run smoother

[406 Q-ship]

Originally Posted by camshaftgsxr

which makes it run smoother

Incorrect sir because you chose to ignore the next sentence that I wrote...

Originally Posted by 406 Q-ship

The 4/7 swap does not make the engine smoother, that was done by racers to get rid of the 5 and 7 firing so close together. Does not work because then 4 and 2 are now sequential.

The LS is a 4-3/7-2 swap to make the engine run smother. LS firing order is 1-8-7-2-6-5-4-3. This is the one racers should do to get the cylinders to not fire sequential. If you renumber a Ford 351 (or all later Ford V8s) cylinders to the same way GM does it, you will see that the firing order is the same (so Ford got it right....ouch that hurts to say).

1-8-4-3-6-5-7-2 STD most V8's
1-8-7-3-6-5-4-2 Swaped 4 and 7
1-8-7-2-6-5-4-3 LS V8s

then 2 and 4 become sequential which just moves it to the right front corner rather than the left rear corner. So no balance improvement nor a performance gain and the has been tested. I have seen tests that say it works on a race engine and I have seen tests that say it does not work.

Originally Posted by 54Caddy

Ford did not get it right, Ford does not use the same cylinder relation as chevy does as far as the left bank being 1 3 5 7 and right bank being 2 4 6 8. Ford is left bank 5 6 7 8 right bank 1 2 3 4. so if you draw a diagram with the two number for the firing order they will not match not even close. GM is totally different than the Ford block. So there is no relation at all between the two

Again incorrect, I said number the Ford like a GM engine and start from the GM number one and you will see it is exactly the same as the LS/LQ series. Ford in red

1 5 2 1
3 6 4 2
5 7 6 3
7 8 8 4

1-8-7-2-6-5-4-3 LS/LQ Firing order
1-3-7-2-6-5-4-8 Ford 351 Firing order

Now if you start both engine on the same cylinder the Ford Firing order becomes

5-4-8-1-3-7-2-6 Oh looky it is the same sequence as the LS.

BTW that diagram does not give the whole issue, you must go throught the whole firing order not just half.

[grs]

The person that put this thread up was not stupid, or dumb. He was ignorant. Ignorant means= lacking knowledge, information,or awareness about something in particular. The person that said he was stupid is not stupid. He is ignorant. He is also a mean person. People who dis respect people should be kicked off the site.

[camshaftgsxr]

Originally Posted by 406 Q-ship

Incorrect sir because you chose to ignore the next sentence that I wrote...


then 2 and 4 become sequential which just moves it to the right front corner rather than the left rear corner. So no balance improvement nor a performance gain and the has been tested. I have seen tests that say it works on a race engine and I have seen tests that say it does not work.



Again incorrect, I said number the Ford like a GM engine and start from the GM number one and you will see it is exactly the same as the LS/LQ series. Ford in red

1 5 2 1
3 6 4 2
5 7 6 3
7 8 8 4

1-8-7-2-6-5-4-3 LS/LQ Firing order
1-3-7-2-6-5-4-8 Ford 351 Firing order

Now if you start both engine on the same cylinder the Ford Firing order becomes

5-4-8-1-3-7-2-6 Oh looky it is the same sequence as the LS.

BTW that diagram does not give the whole issue, you must go throught the whole firing order not just half.

good info, but why does anyone make a 4/7 swap cam? it seems like its only going half way in sorting out the firing order.

[D.FENS]

There was a pretty extensive article in, IIRC, Car Craft mag a few months ago regarding the hows and whys of the LS firing order change. In so few words the change was made to reduce NVH (noise, harshness, vibration).

In other news, in the early EARLY days of NASCAR engine builders would reverse the rotation of the engine to change the torque loading of the chassis in the turns.

[Pyrotechnic]

Originally Posted by 406 Q-ship

If you renumber a Ford 351 (or all later Ford V8s) cylinders to the same way GM does it, you will see that the firing order is the same (so Ford got it right....ouch that hurts to say).

Everyone always mentions the LS order being the same as The Ford 351W and late model 302...and it most certainly is, but don't ever get the notion that GM copied Ford on this one, or that Ford did it first.

A little know fact is that the Cadillac 472-500-425-368 use the LS firing order. The Cadillac 472 was introduced in 1968. The Ford 351W was introduced in 1969. GM used the firing order before Ford did. I've also read that the head design of the LS motor is loosely based on the Cadillac V8 as well.

GM actually did get it right!

[1LowToy]

Believe it or not firing order can be changed. Not to the 1 2 3 4 5 6 7 8 but it can be changed. I.e. marine engines. There are several modifications to marine engines one of which includes a change in firing order and the direction of which the motor is turning. I also dabled in Fords. I put a 351 windsor cam in a 302. It all works but the firing order is different between the two motors. Really pissed of the next mechanic that worked on the motor too He couldn't get that thing fired up for nothing using the 302 firing orfer.

[Hulk Will Smash]

I have a short stroke Merlin 3 572" race motor for my offshore boat that has a 4/7 swap. The cam guy insisted on it and cited "harmonics" over my likelihood of screwing thing up when tuning... I was just writing the check and turning wrenches though. I've never seen the spintron footage at any of that crap. I just try to keep the rods in the inside and me on the outside...
Posted via Mobile Device

[gGMC DOG]

here's a link with several pages on the subject
http://www.speedtalk.com/forum/viewt...2ef81e0fd5b562

[Hulk Will Smash]

Originally Posted by gGMC DOG

here's a link with several pages on the subject
http://www.speedtalk.com/forum/viewt...2ef81e0fd5b562

Awesome! Hahaha. 3rd post there... Bob's my cam guy that I referenced above.
Posted via Mobile Device

[oldschool18]

How to become less ignorant......... the following was the best answer givin by Yahoo.



That is an excellent question, how to be less ignorant. At least you know you might be ignorant - it is worse to be ignorant, and not know!

Firstly, don't ever be afraid to ask other people questions. I mean, in the real world, especially people older than you. That's a major way of learning.

I recommend starting a program of learning by reading your local newspaper as often as possible. You will be introduced to an enormous amount of different issues.

At first, many issues may seem difficult to follow. But, as you build more and more knowledge, your learning will become faster, and more pleasurable.

If you are a curious person, the things you will discover from reading a good newspaper will lead to you later going after more specialist knowledge in books, etc


Well I guess were all ignorant about something....every last one of us

[BigBlocksRule]

The top sportsman engine builder in the country was asked the reasons he installs 4/7 swaps in his customer's engines.
"Because they expect it" was his answer. It may pick up a couple of foot lbs of torque, but not much more than that. It may run a bit smoother, but bearings look the same at tear-down with either cam.

[406 Q-ship]

Originally Posted by camshaftgsxr

good info, but why does anyone make a 4/7 swap cam? it seems like its only going half way in sorting out the firing order.

Because sometimes racers can be lemings. There are plenty of modifications done that don't work any better than what the OEM did.

Originally Posted by Pyrotechnic

Everyone always mentions the LS order being the same as The Ford 351W and late model 302...and it most certainly is, but don't ever get the notion that GM copied Ford on this one, or that Ford did it first.

A little know fact is that the Cadillac 472-500-425-368 use the LS firing order. The Cadillac 472 was introduced in 1968. The Ford 351W was introduced in 1969. GM used the firing order before Ford did. I've also read that the head design of the LS motor is loosely based on the Cadillac V8 as well.

GM actually did get it right!

I never said that Ford was the first, just that they did it right. For all I know that Cadillac, Oldsmoble, or Chrysler came up with the better firing order in the 1950's. For all I know, Chevrolet engineers may have came up withit in their 1st V8 in 1917!.

[BigBlocksRule]

Keep in mind that you're limited in what you can do by the configuration of the crankshaft...you can't fire a cylinder when the crank is on the intake stroke!

[babyJay]

Originally Posted by BigBlocksRule

Keep in mind that you're limited in what you can do by the configuration of the crankshaft...you can't fire a cylinder when the crank is on the intake stroke!

I've seen it done, but not with good results.

[BigBlocksRule]

^ yeah, it's surprising that one will even fire with the dizzy 180* out, but it will.
And really makes you feel stupid when you figure out what the problem is