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Author
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Topic: SBF Firing orders
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wvcat
Gearhead Posts: 299
From: New Cumberland,WV
Registered: May 2001
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posted 01-21-2006 10:08 AM
   
I have been wondering for a long time why ford made the firing order different on the 351w than on the 289/302's. It seems to me that there must be a reason. I just wonder if there is an advantage to using a cam with on firing order over the other. Has there ever been testing to determine if there is any advantage with either one? Anybody have any info or experience?
Thanks
John------------------
Thanks
John
(wvcat)
http://www.geocities.com/wvxr7cougar/wvcat_01.html?989286238390
http://mysite.verizon.net/vzeo7ta1/
Thanks
John
(wvcat)
http://www.geocities.com/wvxr7cougar/wvcat_01.html?989286238390
70[/URL]
[URL=http://mysite.verizon.net/vzeo7ta1/XR7[/URL]Restomod...wvcat
66 coupe project...she needs a name!!!
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Scott H
Gearhead Posts: 901
From: Chicago area
Registered: Mar 2005
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posted 01-21-2006 10:13 AM
The pressures from the cylinders firing in a different order puts a different load on the crankshaft journals.
I don't believe there is any horsepower to be gained, but that is opinion only, someone may have facts that state otherwise.
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capri man
Gearhead Posts: 7611
From: doerun, ga.
Registered: Nov 2000
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posted 01-21-2006 10:18 AM
they claim that the 1-5 firing order puts to much strain on the number one main bearing because the two cyls fire almost simultaniously on that bearing. ------------------
mike r
racing is real
everything else is just a game.
81 capri-302-7.25 @93mph 1/8
1.54 60ft 50 % of the fun dragracing is meeting people who will give you the shirt off their back to wipe the grease off your hands.
M&M member #839 http://i2.photobucket.com/albums/y6/mike470/adel2.jpg
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bifs66
Gearhead Posts: 286
From: Maryland
Registered: Apr 2000
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posted 01-21-2006 08:29 PM
I personally think that Ford wanted to use a different firing order than the SBC! So, they came up with a new firing order for the '69 351W, and eventually implemented this new order on the 5.0s in 1982.------------------
Bernie Frank
66 Fastback restomod (12.8 @ 112mph)
85 GT (preserved)
2000 SVT CONTOUR
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rustang@home
Gearhead Posts: 144
From: Clarion, PA
Registered: Jan 2004
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posted 01-21-2006 09:48 PM
Every time I talk to the cam tech lines, they always recommend the late model firing order. I've heard that bearing loading was the main reason, but when I asked one of the cam tech guys if there was a hp advantage, he said "the Nascar guys all run the 351 firing order, what's that tell ya?"
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Scott H
Gearhead Posts: 901
From: Chicago area
Registered: Mar 2005
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posted 01-21-2006 10:40 PM
That tells me they want their crankshaft to survive over 8,000 rpms.
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Scott H
Gearhead Posts: 901
From: Chicago area
Registered: Mar 2005
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posted 01-21-2006 11:00 PM
quote:
Originally posted by bifs66:
I personally think that Ford wanted to use a different firing order than the SBC!
Ford is 1-5-4-2-6-3-7-8
or 1-3-7-2-6-5-4-8
Chevy is 1-8-4-3-6-5-7-2 They didn't need to change it to be different than GM
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bifs66
Gearhead Posts: 286
From: Maryland
Registered: Apr 2000
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posted 01-22-2006 03:31 PM
Scott... It appears by the numbers that the old SBF Ford firing order is different than the SBC. HOWEVER, Chevy numbers their cylinders differently than Ford. So, if you compare the actual physical firing order of the two engines, you will find that they are the SAME. Check it out for yourself.------------------
Bernie Frank
66 Fastback restomod (12.8 @ 112mph)
85 GT (preserved)
2000 SVT CONTOUR
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Scott H
Gearhead Posts: 901
From: Chicago area
Registered: Mar 2005
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posted 01-22-2006 03:49 PM
Bernie,
You are correct that Chevy numbers their cylinders different than Ford, Chevy does odd numbers on the driver's side and even numbers on the passenger side.
Ford starts on the passenger side and numbers them in order of 1,2,3,4 etc.The way I map it out according to cylinder diagram is as follows: Ford starts at Right Front and goes to Left Front, then right rear before going to middle cylinder #2 Chevy starts at Left front and goes to Right Rear, before going to the middle cylinder #4. They still don't match.  [This message has been edited by Scott H (edited 01-22-2006).]
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bifs66
Gearhead Posts: 286
From: Maryland
Registered: Apr 2000
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posted 01-22-2006 09:01 PM
Hey.. We got ourselves a neat little subject (firing order) to yak about during these otherwise boring winter months. In response to your last post, I dug out the old reference books and reviewed the SBC/SBF cylinder layout and firing order: SBC (front) 18436572
1 2
3 4
5 6
7 8 SBF (front) 154263798
5 1
6 2
7 3
8 4
At first they appear different....but firing order is cyclical, so consider after the SBC fires the #2 cylinder, it fires the #1 then the #8. This begins to look suspiciously like the Ford order. They appear different because one enters the cycle at a different cylinder, but they end up the same physical order. Right??? ------------------
Bernie Frank
66 Fastback restomod (12.8 @ 112mph)
85 GT (preserved)
2000 SVT CONTOUR
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Mark Ugrich
Journeyman Posts: 26
From: Waukesha, Wisconsin,U.S.A.
Registered: Jan 2006
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posted 01-22-2006 09:10 PM
If my memory serves me...the ford engineers wanted to reduce stress on the #3 main bearing in truck applications.
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scottford351
Gearhead Posts: 118
From: reedsville ohio usa
Registered: May 2003
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posted 01-22-2006 10:12 PM
quote:
Originally posted by bifs66:
Hey.. We got ourselves a neat little subject (firing order) to yak about during these otherwise boring winter months. In response to your last post, I dug out the old reference books and reviewed the SBC/SBF cylinder layout and firing order: SBC (front) 18436572
1 2
3 4
5 6
7 8 SBF (front) 154263798
5 1
6 2
7 3
8 4
At first they appear different....but firing order is cyclical, so consider after the SBC fires the #2 cylinder, it fires the #1 then the #8. This begins to look suspiciously like the Ford order. They appear different because one enters the cycle at a different cylinder, but they end up the same physical order. Right???
You better recheck the sbf firing order again! I think #9 is out of place 
They are the same order  ------------------
91 LX 398w street/bracket 6.67@105 1/8 60FT 1.51
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Scott H
Gearhead Posts: 901
From: Chicago area
Registered: Mar 2005
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posted 01-23-2006 03:22 AM
Now that really is an interesting observation!
I'll agree they eventually cycle thru the cylinders in the same physical layout, but firing orders and engine timing don't start in the middle of the published cycle.
And the firing order isn't stated as "Left Front, Right Rear, Right forward Center, Left Foreward Center, etc".
Going back to your original statement, that Ford wanted to use a different firing order than Chevy....I still say the published firing orders (as would be commonly memorized by most mechanics and enthusiasts) are different.Maybe after this we can discuss the difference between Ft.-Lbs of torque and Pounds-Feet of torque.
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ukracer
Gearhead Posts: 172
From: South Wales UK
Registered: Apr 2003
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posted 01-23-2006 07:17 AM
I have been thinking about this recently as luck would have it - think of a V8 as being 4 V twins in a row - then three pairs fire as V twins, but one pair does not. Same applies with either Ford firing order
15426378 gives:
1&5 (V twin)
4 (odd one out)
2&6 (V twin)
3&7 (V twin)
8 (the remaining odd one)
or 15726348 gives:
1&5 (V twin)
7 (odd)
2&6 (V twin)
3 (odd)
4&8 (Vtwin)
Am I the only one to notice this? Why would they not fire them a 4 V twins? maybe it can't be done, haven't thought it throough yet.
Cheers, Martin
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Rustang
Gearhead Posts: 821
From: Clarion PA
Registered: Nov 2000
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posted 01-23-2006 08:19 AM
All this talk of Ford and chebby's firing orders, check this out...the new Chebby motor (the LS6?) changed its firing order to the same as Ford's 351W! 
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