Which Firing Order?April 20 2008 at 7:39 AM
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|Jim Pinkerton (Login Smuck1)|
from IP address 184.108.40.206
'95 5.0 Litre with 303 cam; which firing order is correct -- 137 .... or 154... ? And, why is there reportedly a difference between an FI and a Carbed engine? Thanks.
orderNo score for this post
|April 20 2008, 11:31 AM |
not all 5.0/ 302 carbs use the 154.
see site:No score for this post
|April 20 2008, 5:14 PM |
Firing OrderNo score for this post
|April 20 2008, 8:02 PM |
History LessonNo score for this post
|April 30 2008, 10:00 PM |
Gather round boys and girls, while I tell you a story of the olden days and the magic incantations that made these engines work.
In 1961, at the start of the 1962 model year Ford introduced the first of its new 90 Degree "V" engines, the 221cid. This engine had the same firing order as its bigger and older brothers, the old "Y" block, and the FE, and MEL engines; 15426378. This firing order was maintained through out the growth to 260, 289, and 302cid. During the lead-up to the introduction of the 351 in 1969 it was ascertained that a knocking noise was coming from the front main bearing of the new engine. The cause was tracked down to a combination of the accessory belt load, increased bearing loads from the longer stroke, and the fact the two front cylinders fired one after the other. By moving the two opposite firing cylinders more centrally within the block, 3 and 7, the knocking problem was cured. This led to the 351 having a firing order of 13726548. No changes were required to any major engine components other than the camshaft. As a side note, in 1969, there was no such thing as a 351W, for Windsor, Ontario. There was only "the" 351, the only 351. The "W" and "C" designations were only introduced in 1970, with the "M" designation added in 1975.
But, I digress; When the 351 Cleveland was introduced in 1970 and the 400 in 1971, they used the "137" firing order, as did the 351M.
The next phase of our story came to light with the introduction of the 5.0Litre HO in 1982. The quickest and easiest way for Ford to boost the performance was to use the old 351W camshaft from the early 70's. They had been using this cam in their marine engines all along anyway, both 302 (5.0L) and 351W (5.8L). Using this cam required changing from the "154" firing order to the "137". Long before Ford started doing this, I was installing the early 351W camshaft in 289's and 302's as an easy and inexpensive way to really wake up the little engines using factory parts. Non HO motors continued using camshafts with the "154" firing order.
When the roller lifter valvetrain was introduced in 1985, the HO's continued to use the "137" firing order. All the subsequent updates to HO camshafts and the Ford Racing offerings were also "137"s. Non HO, roller lifter engines used the "154" firing order.
Now, in my mind, all this begs one question; why did Ford not change the firing order of all 302(5.0L)'s to the "137"? I don't know, but would love to know. Perhaps someone out there can shed some light on this for all of us.
That ends our story for now. As with all things automotive, and especially Ford, I'm sure more will be added later.
orderNo score for this post
|May 1 2008, 7:56 AM |
yes all 351 use 13726548 order. why the 5.0 went to it--- my guess is with the thinner blocks and 50oz balance keeps the load off the front mains. imo that 50oz. is a crank/ block breaker at high rpm
Methinks it's the same reason that Chevy.......No score for this post
|May 1 2008, 1:02 PM |
did so for the new LSI's and racer's use the same too in custom BBC cams: better fuel distribution and less chance of ignition cross-over via the spark plug routing.
The new Gen.III "LS1" motors have a different firing order than previous smallblocks. The firing order for the Gen.III smallblock and the 2001 8.1 liter (496 cubic inch) big block is 1-8-7-2-6-5-4-3. Eight individual ignition coils are computer controlled. No conventional distributor is used. The new firing order smooths out the running motor and eliminates the previous problem of the #5 and #7 cylinders firing right next to one another and causing fuel and air distribution problems. In case you were wondering, the firing order for the Gen.I, II and previous "Vortec" motors is 1-8-4-3-6-5-7-2.
the orderNo score for this post
|May 1 2008, 3:14 PM |
fuel inj. doesn't have a mix problem and air moving in the same direction is not going to rob the next cly. in the order. the change has more to do with crank twist. daul planes are also a thing of the past. check out the old flat head Ford V8, what do you see? remember they had only 3 main caps
But......No score for this post
|May 1 2008, 4:03 PM |
the G.M. website link does state that the EFI equipped LS1's can have (or could have had) mixture problems with the old f.o. Don't think they run dual planes on this quite modern engine either. Maybe the highly paid G.M. engineers are wrong???
big bucks???No score for this post
|May 1 2008, 6:03 PM |
yep, big buck GM dudes got it down pat.so what"s the last cly. to fire in the new GM order? #3 i think and guess what follews after the last one--- it's cly # 1 right next to each other. i would say that;s what Ford did also---1542 swap to 1372 on 351 engines. the new GM got a Ford lay out, what with that?