Rod Journal Size?

[schaferstephen]

Can someone confirm that the rod journals for 200/250/240/300 cranks is 2.1232"? As per Bob's build, I'm (trying) to use early forged 300 rods... Custom pistons have the .912 pin as per the pin size on the rods... But my disgruntled shop just called telling me that the journals (the big end) were too big for my crank... Have I done messed up, or what?

Thanks yall.

 

[bubba22349]

Yes the crankshafts standard Rod bearing journal size for all the small sixes including the 200, 250, plus also the big sixes 240, & 300 will measure from 2.1228 to 2.1236. The rod bearing part number is 2600 CP is the same for a 250, 240, and 300. Are you sure you have a set of 300 Rods? Good luck

 

[schaferstephen]

Pretty darn positive...I'll double check but I'm pretty darn sure! I'm gonna feel real stupid if I ordered the wrong rods

 

[bubba22349]

What casting number do they have?

 

[schaferstephen]

The rods are C5TZ-6200-A.

 

[bubba22349]

Not sure on that number might be the heavy duty 300 truck rod used with the forged steel crank. Most of the forgoing numbers I have seen for the early 300 truck rods were C5TE-6200-A.
Measurements should be 6.2097 long center to center with a .912 pin don't have the big end measurement handy but my guess is that it would be around 2.250 - 2.275. If you have a new bearing measure the shell thickness then add that too the 2.1236 crank journal size plus the oil clearance of .015 to .025 and that should get you very close on the big end measurement. Good luck

 

[schaferstephen]

It is an E. I'm trying to attach a picture of the rod w/ the box and code, but I can't figure out how to attack a picture...

 

[schaferstephen]

Appreciate the help, boss! I know if has a .9122 pin, I ordered custom pistons that also have a .912 pin... Just trying to figure out the crank bearing deal.

I'll get it eventually.. Thanks!

 

[bubba22349]

If it's an E as in C5TE- then it's the right con rod. Have you measured the crank journal to see if it's Std. Or been ground under size? Info on posting pictures is in this below link. Good luck
viewtopic.php?f=47&t=48863

 

[schaferstephen]

That's a negative, couldn't tell you if it was ground down or not... If it was, I assume all I'd need is an oversize bushing?

Thanks for the info

 

[bubba22349]

Yes that's correct you would just use an over size bearing. If you have the bearings that came out of your 250 just check the back of the shell for an over size marking, if there's no marking or Std. = it's still the factory Standard size.