FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: frnkeore on May 29, 2021, 02:07:23 AM
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Ford used the 1-5-4-2-6-3-7-8 firing order, starting with the flathead, up until release of the 351W, when it changed to 1-3-7-2-6-5-4-8. They later changed the 302, to that FO also and I believe all V8's after that, have the 1-3-7-2-6-5-4-8 FO.
I'm about to have Howards grind a cam for my Edsel engine. When I had them grind my 302 cams, they recommended the late FO and told me, that most customers order the late FO for ALL SBF's.
So my questions are:
1. Has anyone on this forum built a FE with the late FO and if so, was there any advantage or detriment to it?
2. What are the advantages of the late FO and is there any factual info on why Ford went to it?
I think I red somewhere, that they change the 302 FO for harmonic reason and it improved the longevity of the late blocks.
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Probably wouldn’t be a detriment but it probably won’t show any advantage either.
The biggest issue is finding cores for the FE with that firing order. The cam core has to be made with that order. The cores for the SBF are plentiful because the SBF was made with both orders from the factory.
I’ve used different orders with different engines, have tried the Coyote firing order on BBFs, tried the 4/7 swap on a Pontiac, etc. I think a lot of it is done for the novelty but it doesn’t hurt to try I guess, if the cores are available.
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This video from David V. discusses why a firing order change would be beneficial to a specific (non-FE) application. Rather interesting topic even if rather extreme.
https://www.youtube.com/watch?v=euaLiD1KY74
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When I was at Ford, I was told that the firing order swap was done mainly for structural reasons, to relieve the "double-hit" on bearing cap #1. Sure, you now move the pummeling to #5 cap, but it is much more massive and you have the flywheel right there with all of its inertia.
Obviously there was warranty benefit, or they wouldn't have gone to the trouble. To me the gas flow benefits of the swap would be marginal.
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When I was at Ford, I was told that the firing order swap was done mainly for structural reasons, to relieve the "double-hit" on bearing cap #1. Sure, you now move the pummeling to #5 cap, but it is much more massive and you have the flywheel right there with all of its inertia.
Obviously there was warranty benefit, or they wouldn't have gone to the trouble. To me the gas flow benefits of the swap would be marginal.
Yep, and you have the 2-6 pummeling as well.
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When I was at Ford, I was told that the firing order swap was done mainly for structural reasons, to relieve the "double-hit" on bearing cap #1. Sure, you now move the pummeling to #5 cap, but it is much more massive and you have the flywheel right there with all of its inertia.
Obviously there was warranty benefit, or they wouldn't have gone to the trouble. To me the gas flow benefits of the swap would be marginal.
I had read somewhere years ago that the change in the sbf firing order with the introduction of the 351W was done to revise main bearing loading,at the time I didn't know what that meant,but based on your post it becomes a little more clear.
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About a zero ho gain on the 4/7 swap from my old Chevy shop guys (oophs!) on even near 600+ h,p. BBC's. They did see about a 1-3 h.p.+ change on the dyno (admittedly, weather alone could have been the variable) but zero or near zero e.t. reduction. Btw, they experimented with both big h.p. Comp. Elim. SBC's and BBC's as noted but did so only for alleged h.p. gains....no mention of bearings loads.
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Same story from a bearing manufacturer. Our lead engineer at F-M said the the change was made to improve bearing longevity. He said that the issues arose with increasing belt loads and that later serpentine systems made it worse.
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Ford used the 1-5-4-2-6-3-7-8 firing order, starting with the flathead, up until release of the 351W, when it changed to 1-3-7-2-6-5-4-8. They later changed the 302, to that FO also and I believe all V8's after that, have the 1-3-7-2-6-5-4-8 FO.
The Flat Head firing order was: 1-5-4-8-6-3-7-2. It's the GM 7-2 swap in the picture.
(https://hosting.photobucket.com/albums/aa150/Sleepercp/Engine%20stuff/.highres/scan0001-2.jpg?width=590&height=370&fit=bounds) (https://app.photobucket.com/u/Sleepercp/a/e270eea0-14be-4a48-9b63-bd20c16995a2/p/d7cfda32-f5c5-4f4d-b271-fe37d764deb0)
I talked with Kaase about it at the 2004 Engine Masters. He told me that on his 750"+ mountain motors they don't see any HP but the cranks can last 3 times as long compared to the standard 1-5-4-2-6-3-7-8.
Watch the firing order in one of the animations/simulations that was done for my A-460 tunnel ram : (standard 460 firing order)
(https://hosting.photobucket.com/images/aa150/Sleepercp/mid_plenum.gif?width=590&height=370&fit=bounds) (https://app.photobucket.com/u/Sleepercp/a/e270eea0-14be-4a48-9b63-bd20c16995a2/p/36e8022e-46c8-4532-b2ca-f2a21548d82b)
Every firing order (depending on when you start counting, fires the Big Circle ( outer circle of clys) then the inner smaller circle. In the animation start the count at #8. We were trying to figure out if we could see a pattern in the intake distribution by changing the firing order, but no matter what you do you will always have clys stealing mixture from another.
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Ford used the 1-5-4-2-6-3-7-8 firing order, starting with the flathead, up until release of the 351W, when it changed to 1-3-7-2-6-5-4-8. They later changed the 302, to that FO also and I believe all V8's after that, have the 1-3-7-2-6-5-4-8 FO.
The Flat Head firing order was: 1-5-4-8-6-3-7-2. It's the GM 7-2 swap in the picture.
(https://hosting.photobucket.com/albums/aa150/Sleepercp/Engine%20stuff/.highres/scan0001-2.jpg?width=590&height=370&fit=bounds) (https://app.photobucket.com/u/Sleepercp/a/e270eea0-14be-4a48-9b63-bd20c16995a2/p/d7cfda32-f5c5-4f4d-b271-fe37d764deb0)
I talked with Kaase about it at the 2004 Engine Masters. He told me that on his 750"+ mountain motors they don't see any HP but the cranks can last 3 times as long compared to the standard 1-5-4-2-6-3-7-8.
Watch the firing order in one of the animations that was done for my A-460 tunnel ram : (standard 460 firing order)
(https://hosting.photobucket.com/images/aa150/Sleepercp/mid_plenum.gif?width=590&height=370&fit=bounds) (https://app.photobucket.com/u/Sleepercp/a/e270eea0-14be-4a48-9b63-bd20c16995a2/p/36e8022e-46c8-4532-b2ca-f2a21548d82b)
Every firing order (depending on when you start counting, fires the Big Circle ( outer circle of clys) then the inner smaller circle. In the animation start the count at #8. We were trying to figure out if we could see a pattern in the intake distribution by changing the firing order, but no matter what you do you will always have clys stealing mixture from another.
If you order a 60mm BBF cam from Comp with around 1" lift, the 15486372 FO is what you get.
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Same story from a bearing manufacturer. Our lead engineer at F-M said the the change was made to improve bearing longevity. He said that the issues arose with increasing belt loads and that later serpentine systems made it worse.
Funny - Sometimes the serpentine belt made things better! I participated in the teardown of a 3.0L Taurus V6 that came back as a dealer warranty return. The stated cause was "bolt in oil pan". No customer complaints or odd sounds, and good oil pressure while running.
Sure enough, when we pulled the drain plug and looked up with a light, you could see a big fat bolt head sticking into the plug hole. Upon dropping the pan, we found that both #1 cap bolts had broken and were laying in the pan, along with the cap. The serpentine belt tension was holding everything up just fine :o :o