crankshaft

[89Bronco58]

are the ford 351w and 302 crankshafts the same, and i kno the cams are different sizes but why the difference in firing order?...the cam lobes in different places so different valves open at different times, unlike the 302 would...so yeah why the difference in firing order?

 

[Seabronc]

302 HOs used 351 firing order and that would make it necessary to have the same design crank shaft. The reason for the change as far as I can find is that the 351 firing order is easier on the bearings, not sure why. That is what I found in searching on the subject.

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[Seabronc]

are the ford 351w and 302 crankshafts the same, and i kno the cams are different sizes but why the difference in firing order?...the cam lobes in different places so different valves open at different times, unlike the 302 would...so yeah why the difference in firing order?

31897[/snapback]

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No, the standard 302 and 351 don't use tha same crank shaft. However what you have is not a standard 302, you have a 302 ** which is more than a cam change. It is a 302 built like a 351 which includes a 351 style crank. It just doesn't have the displacement of a 351. It also uses 302 connecting rods that are shorter than a 351.

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[BLADE262US]

The only thing different on a 302 ** and a normal 302 is the combustion chamber shape and factory forged pistons with metric stainless steel rings, and possibly a slightly higher lift on the cam. The crank is the same as a standard 302 . The things thats different between a 302 crank and a 351 crank are 1 after 78 the 302 went to a very light weight crank very low rotating mass this is the reason for the 50 oz weight required on the flywheel of all 302,s after 78/79 or somewhere in there . 2 the journal size is different ( 302 is smaller ) And for those in doubt and want to try to put one in watch what happens as the crank trys to push the piston an extra 1/2 inch into the head a 302 has a throw of 3 inches and a 351 has 3.5 inches both motors have a 4 inch bore ( 302 = 3.14X2X2X3=37.68X8=301.44 ) 351=3.14X2X2X3.5=43.96X8=351.68) And the firing order issue you are right Seabronc that was done to lessen the load on one jouranl at a time in a 302 cylinder 1 fires then 5 directly across from it ******* the crank and mains 351 firing order spreads it out you can put a 351W cam in any 302 so long as you time it for a 351 and you can put a 302 cam in any 351W as long as you time it for a 302 . /emoticons/[email protected] 2x" width="20" height="20" />

 

[Seabronc]

Blade, won't puting a 351 cam in a standard 302 and vice versa open the valves at the wrong time in relation to the piston position for the cylinders that are swapped around? I would think the crank shaft would also have to be be modified to correct for this.

Edited out a duhhh! statement. Guess I should have gone to look at the book before winging it :blush:

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[BLADE262US]

LOL did ya figure it out now /emoticons/[email protected] 2x" width="20" height="20" />