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Author Topic: Anybody played around with changing the firing order on a SBF  (Read 2500 times)
Brent Clay
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« on: February 18, 2013, 07:21:54 AM »

Seems to me there could be some power to be made by changing the firing order.... for instance, why does Ford have #7and 8 cylinders one after the other? wouldn't it be better to expand that energy to another part of the crank, instead of back to back firing of cylinders on the back part of the engine.  I feel this could be beneficial, any one have ideas on this or done such a thing?
I think this would also be easier on parts and bearings....

I will touch more on this later,, my son is crying and I have to Go...

Brent
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161854
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« Reply #1 on: February 18, 2013, 02:28:55 PM »

    Brent try a Windsor firing order. 13726548. Thereare only three possible firing order combinations for a 90*V8 no one has tried the other on a Ford cam yet.
         Randy
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Brent Clay
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« Reply #2 on: February 18, 2013, 02:48:07 PM »

I have done that in the past on my 347...  I was trying to think outside the box and have the motor fire equally from the front corner to the back corner and criss cross back and forth to put equal stress on the crank and block.

for example :  fire number 18275463 (this is just and idea) Im not even sure if this would work! It just "LOOKS" to me like this would be efficient and less stress on the rear main bearings, not to mention the heat of having two cylinders firing right after eachother.

Am I crazy on this thinking, could a motor work if a custom cam was made to fire the cylinders in this pattern?????  I really dont know Randy, thats why I am asking! 

By the way, what is the other firing order Randy?

Brent
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FordRacing250
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« Reply #3 on: February 18, 2013, 05:15:52 PM »

Big Block f/o and flathead f/o I believe but cant recall them off the top of my head
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« Reply #4 on: February 20, 2013, 09:06:49 AM »

       Brent,
       You only have four "pairs of pistons , meaning ( in a 90* v-8) two are up at the same time for "possible firing" These are 1and 6, 5and 3, 4and7 and 2 and 8.
This make four "possible" firing orders but 1 fires 3 on a bank in a row and creates horrible harmonics. Here are the four possibilities . 15426378,13726548,15486372, and the bad one,13486572 which ius a crank breaker for obvious reasons. Cadillac ( with different cylinder numbering) I think ran the third order. It is doubtful there is any "magic" in the swaping of firing order, but that's just "my" opinion.
     Randy
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Brent Clay
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« Reply #5 on: February 20, 2013, 09:12:21 AM »

Thanks Randy,

I know what I was asking was impossible the way the motor is designed...... however, would it be beneficial to think about a different design in the crank to allow a totally different firing order.... (im just thinking outside the box here and I know it sounds stupid, however, i just was thinking the other day when I was looking at this shortblock and wondered  "WHAT IF" ??? 

Thanks again!

Brent
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289nate
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« Reply #6 on: February 20, 2013, 09:57:22 AM »

I've only heard of people using the old and later H.O. firing orders on a SBF.  Chevy numbers their cylinders differently but share the same firing order.  So it sounds different from a Ford but is actually the same as one of them.  SBC guys will also have cams ground to change the firing order (I'm thinking the same as the difference between an old and H.O. firing order on a SBF) and call it a performance upgrade.  Some swear by it while others say it's splitting hairs. 

If there was an advantage I would think it would be used in NASCAR.  :huh:

Here is a flat crank (like in a Ferrari) V8 firing order.  http://www.google.com/imgres?imgurl=http://www.projectm71.com/V8block.jpg&imgrefurl=http://www.projectm71.com/Cross_FlatPlane.htm&h=297&w=237&sz=18&tbnid=cBrLD2_y5uszDM:&tbnh=90&tbnw=72&prev=/search%3Fq%3Dflat%2Bcrank%2Bv8%26tbm%3Disch%26tbo%3Du&zoom=1&q=flat+crank+v8&usg=__ZdCVh4dHl1NC9nzvVpATdxNHF0k=&docid=1EqPF0k9xnTVFM&hl=en&sa=X&ei=KwAlUZvFCbCUigLkoYGYDA&sqi=2&ved=0CEoQ9QEwAw&dur=11633
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289nate
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« Reply #7 on: February 20, 2013, 10:00:58 AM »

Whoops, that's just how they number the cylinders.
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289nate
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« Reply #8 on: February 20, 2013, 10:08:40 AM »

Check out post number three.  Oh well. LOL

http://forums.hybridz.org/topic/70271-diy-180-degreesingle-planeflat-plane-v-8-crankshaft%E2%80%A6/
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161854
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« Reply #9 on: February 22, 2013, 08:39:41 AM »

    "flat" cranks are a waste of time and money , been there , done that.
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rmcomprandy
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« Reply #10 on: October 12, 2015, 02:00:11 PM »

       Brent,
       You only have four "pairs of pistons , meaning ( in a 90* v-8) two are up at the same time for "possible firing" These are 1and 6, 5and 3, 4and7 and 2 and 8.
This make four "possible" firing orders but 1 fires 3 on a bank in a row and creates horrible harmonics. Here are the four possibilities . 15426378,13726548,15486372, and the bad one,13486572 which ius a crank breaker for obvious reasons. Cadillac ( with different cylinder numbering) I think ran the third order. It is doubtful there is any "magic" in the swaping of firing order, but that's just "my" opinion.
     Randy

There is one more which also fires ALL one bank then the other bank; 13786542.  Whichever firing order that allows the most even vacuum impulses within the intake plenum which is used sometimes will make a bit more power; another will get more even loading impulses upon the crankshaft yet another might be the best average of both.
« Last Edit: October 12, 2015, 02:03:10 PM by rmcomprandy » Logged
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« Reply #11 on: October 22, 2015, 01:05:20 PM »

   Randy,
       That would really have a strange exhaust note. Might be a "shaker" too.
    Randy
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