351W F.O. changed to 289

[Wade Chamberlain]

Eric - dude, take a step back and think about it for minute before laying into somebody. The explanation that "sport" posted is the one that every ford engine book out there lists as the reason for the change in firing order. You missed the point of it all. It's not about an extra .01 seconds between firing, or fatigue. It's about the combined forces of having two cylinders on the power stroke, sharing the same crank throw, and loading the weakest part of the block.

Think about it for a minute. Sketch it out if you like. With the 154... firing order, cylinder #1 fires, then 90° later, cylinder #5 fires. #1 is only half way through its power stroke, so it's still loading the crank when #5 fires. Now you have TWO cylinders, on the same crank journal, in the weakest part of the block, both on the power stroke. THAT's the problem. Not lack of "rest" period.

[blykins]

I have a question....not trying to argue....but I'm trying to see where my math is off.

You're saying that it takes 2 revolutions for all 8 cylinders to fire.

If you're turning a steady state 6000 rpm, that means that the total of the 8 cylinders have fired 3000 times....correct?

If I am correct there, then each cylinder has fired 375 times in one minute. By that logic, each cylinder has fired roughly 6 times in one second....not 50.

Multiplying 6 times in one second by 8 cylinders would be 48 times per second....If that's the case then.....

It would be .020 seconds between firing. In the old firing order 5 would fire .020 seconds after 1. In the new firing order, 5 would fire .1 seconds after 1.

I think a valid point was made. It's not necessarily the force of the cylinders firing consecutively, but I'm sure you know how natural frequencies eminate. Also, there is a valid point above, with two cylinders following each other, two cylinders are going to be on power stroke at the same time....trying to drive that crank through the main cap. And you know, if they were in perfect sync, it may not be that bad....but they're not in perfect sync.....which adds a lot of imbalance and vibration on that front bearing.

I don't know....I think it's something worth considering. However, if the old firing order cam made so much more horsepower, I would think more racers would be using them and this would be more of a widespread knowledge.

One of the engine builders here at work said that there is a variant of the GM firing order that allows more horsepower to be made.....and it does it because the old firing order has two cylinders right next to each other firing one after the other. This was disrupting the intake charge and basically had two cylinders fighting for the same intake pulse.

It's probably some good things to consider....but with testing, proof, and tact.

[Wade Chamberlain]

Originally posted by blykins



If you're turning a steady state 6000 rpm, that means that the total of the 8 cylinders have fired 3000 times....correct?

Not the total of 8 cylinders have fired 3000 times.....EVERY cylinder has fired 3000 times. Shouldn't have divided by 8.

[blykins]

hehehe....shows what I know.....

[HighPlainsDrifter]

Wow,
Didn't know some people need valium on this forum.

I don't have all the data you requested, but FORD does.
The're R&D has spent thousands of hours and dyno testing to get the 5 liter H.O. mustang to pass emissions and perform better than ANY other Ford engine in history.

Yes 5 and 6 cylinders fire next to eachother on a 5 L engine, but since they are multiport fuel injection there is no cylinder interferance, there will be on a carb'd motor but it still makes more power than the old firing order.

I said the 351 cam was more expensive because it is not mass produced like a 302 [old] cam, the parts house here charges $30 more for a 351 cam.

By the way " Woody " is a great logo, did you get permission from Hanna Barbara to use that logo?
Chill,
Perry.

[Mr.Fixit]

Clay Smith Cams has used that logo for a long, long time.

the new CC poster is not affilited with the cam company.

[blykins]

I'm still confused on the # of firings at 6000 rpm....I must be just dense this morning.

It seems to be from the 1st statement....."It takes 2 complete revolutions for all 8 cylinders to fire."

What am I doing wrong here? If it takes 2 complete revolutions for all 8 cylinders to fire once.......Oh......ok.....I just answered my own puzzle.

If it takes 2 complete revolutions for all 8 cylinders to fire once, then in 6000 revolutions, all cylinders have fired 3000 times...each.

Sorry for being brain dead this morning.

[sharpe 1]

The real advantage to useing the 289 cam is that there are more grinds to choose form to get the performance you are looking for.

[MidOHasp]

blykins,

don't come in here early in the morning claiming like you know what in the hell you are talking about. are you just making this stuff up? did you just sketch out that basic child math on a piece of paper and then turn it upside down and start typing?

seriously, i wonder how many engines you have built. or how many times you have divided 6000 by 2 to get 48. but don't come in here all high and mighty asking stupid questions and acting like you know something.

just kidding - obviously.

Eric,

If that was an attempt at tact, wow. I hope you are better at building engines.

Randy is right, you seem to know some things, but you also seem to think you joined a forum of complete morons. If that's the case, then go home. There are plenty of smart people on this forum who seem to know at least as much as you (some may have even "forgotten more than you will ever know") ..haha.. but usually when someone comes in and makes a false claim, the "knowing" class tactfully and respectfully sets us straight.

No need to berate anyone. I urge you to go back and look at every post that you have torn apart to shreds - nobody has come at you maliciously.

Something like 3 of your 4 posts have been quite assholic. Thank you for bringing some very interesting points to light so that the rest of us can debate the merits and analyze it like grown adult human beings that respect each other and have a common bond.

In the meantime, I probably do not speak for everyone, but I probably speak for a majority - Calm down, take a breath before you post, maybe make a little *bigger* effort at TACT, or go away forever.

Constantly mean and inappropriate posters aren't very welcome here.

That aside, why the firing order change? Which is truly better?

Ford isn't a bunch of 8th graders building engines in shop class. I am guessing that they made the change for a good reason. It doesn't seem to me like they could have saved millions of dollars by making the change. If I'm CEO and I can save millions and millions and maybe there is a slight decrease in quality or performance but nothing really noteworthy, I'll probably do it. But this couldn't have saved anyone any money to CHANGE what was already going down.

Ergo (by the way, throwing some latin in your post doesn't make you come off any more polite)....

I have to imagine that perhaps a WEE WITTLE BIT of R&D went into Ford changing the F/O to the new configuration.

I have an idea... everything is completely maximized right now and we can't do it any better. Let's spend some bucks, start grinding new cams, and switch the firing order to something that is absolutely no better at all, perhaps worse. This idea will make us millions. We will start tomorrow.

Give me a break!!

This all started with someone (WHO KNEW) saying that the old F/O cam was a "bit cheaper" than the new one.

Then Eric gets his panties in a knot over an accusation that he screwed someone out of 12 and a half measley cents.

This is extremely interesting and I would LOVE to see some more research into this. When I get back from out of state this weekend, I will even spearhead some of it.

Peace "dudes".... please!

[MidOHasp]

sharpe... there are?

wow, there were a lot for a 351 when I looked. it was a hard choice then! I can't imagine having more to look for?!

BTW...that isn't me disagreeing, that's me being surprised. I know that tensions are high right now in the "351 F.O. changed to 289" thread.

But I'm a good guy, I promise.

[Toby]

That's it. I'm turning off my tv for good, this thread beats Springer and Okra all to heck. plus a bonus shop lesson! Please renew my subscription.

[rdorman]

EricF = Gasholian moto personified.

We are interested in what you have to say, just not your attitude.

IF you hang around here, I think you will find that you are not dealing with a group of steriotypical motorheads.

What you ARE dealing with, in general, is fairly well educated, intelligent group of Doctors, Lawyers, Engineers, Analysts, Builders of all kinds (cars, motors, etc), Historians etc with a combined total of I would venture to guess in excess of 40,000 years of formal education and many, many times that in experience.

Some of the most influential and notable people in the entire industry are here. Where did you think you where posting? A ricer forum

By the way, you asked several times if some one had data to back up their claims, do you?

Rick