440source

[5.7 hemi]

Are you running the lightened crank? What rod bolts? What rods?

 

[wagonman]

Mine is -17.

-17 also Our kits are within 5 grams of each other. Good sign to Me that they are all individually balanced.

 

[wagonman]

Mine is -4cc. Which should be heavier than the -17cc. However, without having a -17cc piston for comparison it's hard to say how much meat is below the domes.

Do you have a scale? I am taking the pistons down today so the can hone the block to size. I will have them weigh the pistons for a compare.

 

[StreetWedge65]

4340 platinum crank. ARP 8740 for bolts. Platinum series (Scat "H" beam)rods. I assume all their kits come with Scat rods. Wonder why they wouldn't just say Scat rods instead of Platinum Series?

 

[5.7 hemi]

I’ve got the same stuff. I’m just guessing here, but, maybe it’s like rims/tires, even though made/machined the same, they still take different amounts of weight to balance them.

 

[StreetWedge65]

You're probably right. Bottom line, it really doesn't make a hill of beans as long as it works as intended. I was just being curious.

 

[Challenger340]

Do you have a scale? I am taking the pistons down today so the can hone the block to size. I will have them weigh the pistons for a compare.

Look at the Pistons and Rods, if you can not visually see any Balance correction marks on the Tops/Bottoms of the Rods, and on the Pistons under the Pin bosses, etc.,
Then the Crank ONLY(no Balancer/Flexplate or T/Gear attached), has most probably just been Balanced to
an "average" weight of the Pistons(within a couple of grams)
an "average" weight of the Rod Big Ends (within a couple of grams)
and
and "average" Total Rod calculation if nothing has been corrected/ground off the Rod small ends(whatever grams)

The so-called "Balance Job" in the Kits WILL RUN !
But it is a $100-$150 Balance Job and should not be confused with a real Engine Balancing job because there is a difference !

 

[StreetWedge65]

Challenger340 you're correct. I just now discovered, they only balance the crankshafts. Everything else is "ballparked".
Wish they would sell an unbalanced kit. I don't like paying twice for a balance job.

 

[wagonman]

Look at the Pistons and Rods, if you can not visually see any Balance correction marks on the Tops/Bottoms of the Rods, and on the Pistons under the Pin bosses, etc.,
Then the Crank ONLY(no Balancer/Flexplate or T/Gear attached), has most probably just been Balanced to
an "average" weight of the Pistons(within a couple of grams)
an "average" weight of the Rod Big Ends (within a couple of grams)
and
and "average" Total Rod calculation if nothing has been corrected/ground off the Rod small ends(whatever grams)

The so-called "Balance Job" in the Kits WILL RUN !
But it is a $100-$150 Balance Job and should not be confused with a real Engine Balancing job because there is a difference !

Looking at 440s web site they spout off about a precision balance job with pistons and rods balanced to their spec, WTF that means IDK. Also not a 100 to 150 more like 250. I feel like I have been hosed.

 

[451Mopar]

On my old 505" kit, the piston weights varied a maximum of 2.3 grams, the pins by 0.3 grams, rod bearing ends by 0.7 grams, and pin ends by 1.4 grams. By matching up the heavier rod pin ends with the lighter pistons, the variance in the piston/pin/rod weights (Reciprocating end) was reduced to 0.6 grams maximum (if I did not know what the parts weighed, the stackup could have resulted in a maximum difference 4.0 grams. Weighing all the other parts and calculating a bob weight my calculations were within 0.7125 gram of the bob weight stated on the 440 source sheet that came with the kit.
As mentioned this does not include any slight balance difference that might be on the flywheel/flexplate and damper.
For oil weight, I used the same number as 440 source? I really don't know how the "oil weight" number is figured out?
Sort of the same with Balance Factor. 440 source uses the normal 50%, but I have heard of places under and over balancing cranks.

So, depending on the oil weight and balance factor, you could end up with slightly difference bob weights, and depending on the way the different weights stack up, the differences could work for you or against you. As mentioned above, if I just threw the engine together, I could have had a 4 gram difference in reciprocating weight. On the other hand 4 grams is the weight of a sheet of printer paper.