weight balancing connecting rods

[Chaz]

what is up with that oval window and never seen one so wide directly above wrist pin!!

It's just another way to lighten the piston . Four stroke's you don't want to make any oil traps , so you mill the beam on the inside . Two strokes you don't want to add to the crankcase volume , so you mill a slot on the outside .

And yes , to weight match a set of rods , you weigh the big and little ends as well as shoot for an overall that match's your lightest rod .

The cutters are not cheap , but you can taper bore 20 gram's out of the pin's without losing it's integrity ...

[Krazymaan]

I dont think they are oval. its just the angle of the picture creating that Illusion.

Nope, Its oval.

[Krazymaan]

It's just another way to lighten the piston . Four stroke's you don't want to make any oil traps , so you mill the beam on the inside . Two strokes you don't want to add to the crankcase volume , so you mill a slot on the outside .

And yes , to weight match a set of rods , you weigh the big and little ends as well as shoot for an overall that match's your lightest rod .

The cutters are not cheap , but you can taper bore 20 gram's out of the pin's without losing it's integrity ...

Just looked at mine and they are tapered as you mentioned. Not sure if I would have ever noticed that.

[stoker2001]

Dewitt DeWeese (boatworks) taper bored me a set decades ago (78G).still run them to this day in drag 2.5

[Krazymaan]

MIne are at 81 grams.

[rude tim]

Drilled rods! Awesome. I always wanted to do that but was afraid of making a 5 cylinder powered fly cutter! When you drilled the holes did you use a flapper wheel or swizzle stick to polish and radius the holes to remove the stress risers? They look great by the way.

[Krazymaan]

Drilled rods! Awesome. I always wanted to do that but was afraid of making a 5 cylinder powered fly cutter! When you drilled the holes did you use a flapper wheel or swizzle stick to polish and radius the holes to remove the stress risers? They look great by the way.

If your talking to me, I don't know what was used, they came that way. Those were jon wright's from a 2.5 drag engine, which I have on another post with photos.

[HStream1]

Actually they are not Drilled. But Milled in a Jig on a milling machine so all the holes are equally spaced and all rods exactly the same. And YES!!! The holes are smoothed and rounded on all the edges.

Drilled rods! Awesome. I always wanted to do that but was afraid of making a 5 cylinder powered fly cutter! When you drilled the holes did you use a flapper wheel or swizzle stick to polish and radius the holes to remove the stress risers? They look great by the way.