FoxGT

I am assuming most the people know that the 87-92 pistons are forged & 93 are hypereutectic & for both types of engines the rods & crankshaft are cast. If you can only answer one please do so. Thanks in advance to everyone that helps.

1) What year engines are both the crankshaft & rods the exact same as the 87-92 H.O.?
2) Are the 5.0 & the 5.0 H.O. connecting rods & crankshaft different?

roundman

the 5.0 and 5.0 HO crankshafts are different as the two engines have a different firing order. don't know about the rods but I imagine the 5.0 rods are stronger ones.
you can also call the Ford Racing Performance Parts hot line at 586-468-1356 about the other questions.

87mustang347

what r u trying to do anyway

mdvaldosta

no the camshaft is different, and the camshaft is what causes the need for a different firing order... aww roundy...

Why don't you just get an 87+ crank/rods to be safe? Im pretty sure that as long as its a 1 peice seal crank with your same balancer then its identical. I think the rods were the same on all the 5.0's, the only thing that changed was the crank and pistons and their both interchangable between years with the right balancer and flywheel for the crank and the different compression ration between different pistons.

90GTRagtop

So you're saying the same crank shaft can have different pistons at the top when they need to fire in a different order. There are certain permutations that can do this with the same crank, but the timig gear would require a different indexing. However, I kind of suspect Roundy is right.

mdvaldosta

Yes that is exactly what I am saying, and while I see the reasoning in your post - your logic is flawed. The only thing that is changing the firing order on 5.0 vs the 5.0 HO & 351w is the camshaft. As a matter of fact, you can swap the camshafts between the two provided you change firing order. Remember the crank goes around 4 times for every firing cycle, that leaves room for another firing order. Why it was changed? I don't know Im I didn't engineer the motor, but thats the way it is.

And I did some research, the 50oz balancer was first put into use in '81 so as long as you get an '81+ crank your good. The rods appear to be the same from the very first 5.0.

roundman

you're right about the crankshaft but wrong about the number of times it rotates in a firing cycle, it only goes around twice or 720 cranshaft degrees in one firing order sequence. A 90 degree V-8 engine fires a cylinder every 1/4 turn of the crankshaft, so with 8 cylinders, it goes 2 revs not 4.
with the firing order for the 5.0 HO being 1-3-7-2-6-5-4-8 and the regular 5.0 being 1-5-4-2-6-3-7-8 it appears they switched the 3-7 and the 5-4 cylinders in the order. this gets away from the possible problem with two adjacent cylinders (#7 & #8) being back to back in the firing order which sometimes is a problem with induced voltage in the spark plug wires causing one cylinder to fire early if the wires are routed side by side and the insulation is bad.

FoxGT

Oh, I am using my cam anyway. I wouldnt let the money I spent on it go to waste. So are the crankshafts & rods the same size & same material?

mdvaldosta

my bad about the 4 rev's per firing ... twas thinkin 4 stroke at the time... sorry for strokin too much

FoxGT

The strokes without the proper lubrication could mess things up.