I need pics of a 60* rod

[Driver_10]

I need a pic of the side profile of a 60* v6 connecting rod. I need to see if the 60 degree rod has an offset.

Im using eagle 4.3l rods and need to know if the 4.3l 90* v6 and the 3x00 60* v6 have a similar offset on the crank side.

If anyone can provide a good pic of the connecting-rod from the side I would appreciate it.

[project89]

closest one ive got


i have a set of rods at the shop ill see if i can snap u a picture of them tommorow while im at work

[Driver_10]

Try to get a shot that focuses on the side profile of the crank bore. Do it against a white sheet of paper if possible. Im trying to see if stock 3x00 rods are bi-lateral or slightly offset.

[bszopi]

Here is a rod for a 3.6L, since you didn't specify any particular 60V6...

[34blazer]

this is the best one i have

[Driver_10]

When I bought these eagle rods, no one could tell me whether on not they were off-set so I bought them anyway on a gamble.

After I opened them up I found that they were indeed off-set.






notice how the crank bore of the rod has more journel width on one side that the others. I guess what im asking is, ...ahem*

Do 60 degree v6 rods "namely the 3500" have a similar offset?

[bszopi]

When I get home on Saturday, I'll try to take some pictures of 3500 rods I have in the basement.

[SappySE107]

They are not offset, I just checked. Same for the new 2.8-3400 style rods.

[Driver_10]

They are not offset, I just checked. Same for the new 2.8-3400 style rods.

This could be a potential problem. Im worried that there may uneven loading issues with the piston and wrist pin. It could potentially cause radial stress from not being perfectly centered in the piston.

The face of wrist-pin bore seems to ride flush with the face of the crank-pin bore on at least one side. The other side of the wrist-pin bore protrudes 1/16 or so past the face of the crank-pin bore on that side.

I may have to return these rods and special order a set. (crap)

[95Grand-Am]

3400 rods are not offset, but the pistons wristpin bore is off set in the piston.

[ForcedFirebird]

3400 rods are not offset, but the pistons wristpin bore is off set in the piston.

I'll want to verify this. Without taking extremely accurate measurements, the wristpins always looked centered to me on the rods.

John,

What's the total width of the big end on those rods?

The 3500 rods are centered.

[geoffinbc]

Yes the wrist pin bore of offset to the thrust side of the piston, not the same thing we are talking about here. All engines are like that.

4.3L Rods have been offset since the first even fire and semi even fire engine was produced. The offset is .100 and was a result of splitting the rod journal to get an even fire motor.

Our engines have individual throws for each cylinder so it was designed right from the start.

[ForcedFirebird]

Yes the wrist pin bore of offset to the thrust side of the piston, not the same thing we are talking about here. All engines are like that.

4.3L Rods have been offset since the first even fire and semi even fire engine was produced. The offset is .100 and was a result of splitting the rod journal to get an even fire motor.

Our engines have individual throws for each cylinder so it was designed right from the start.

So the ecen fire SBC's are handled the same way?

It would seem that the meat between the journals would be really thin since each rod pin previously shared two rods. I'm unfimiliar with the new generation SBC's, haven't had one apart in years and it was always Gen1's.

[Driver_10]

This leaves me with few options. Im either going to have to

A. have the crank jounels ground down to 2.100 and purchase conventional 5.7l "5.700" con-rods

OR...

B. special order a set 5.700 con-rods with a custom 2.250 crank-bore.

Either option is going to set me back a K.

Does anyone have any ideas?

[geoffinbc]

So the ecen fire SBC's are handled the same way?

It would seem that the meat between the journals would be really thin since each rod pin previously shared two rods. I'm unfimiliar with the new generation SBC's, haven't had one apart in years and it was always Gen1's.

Even fire SBC? They have always been that same way.

V8's have no problems since a pair of cylinders share each throw. There are 4 of them offset 90*. There is no meat between each con rod and they are allowed to touch each other and there is only a fe thou left for side play.


The problem arises on the 4.3L since they modeled it after the small block. They kept the bore spacing and cylinder bank offset the same. When you make an odd fire 90* V6 you have no rod offset. But when they make it into an even fire they narrow the bearing journal of each rod and then offset each throw 30*. The narrowing of the journal happens on one side only and gives extra meat between the split throws. So now you have each rod big end separate by about 0.100" this meat is then take out of the con rod big end and bearing.

Buick did things differently. They decided not to narrow the bearing journal and instead moved the rod over towards the counterweight to allow for material between the split lobe. The con rod beam was offset on the con rod big end but this design still requires offsetting the con rod in the cylinder bore and of course on the piston pin. So on the Buick you keep the big bearing cross section but your now offset on the big end and small end of the rod. It have never been an reliability issue. But for all out competition and drag racing, builders go with a forged odd fire crank and live with the vibration of the staggered firing pulses.