I'm rebuilding an engine on a '91 IROC (first time) and neglected to mark the connecting rod caps when I disassembled it.

Well, now I'm ready to install the crank, bearings and pistons and I'm not sure which way the caps should go.

Is there anyway that I could tell where they go (markings)?

Thanks!

 

damn i hate to say it, so double check me on this, but i think the little ears face the counter weights. actually i tihnk the cap and rod wouldn't be flush with each other if you reverse them. you d oat least have the right cap on the rod it came off of don't you? if not i'd be checking them for roundness.

 

I think you shoud take em to a machine shop and let them get them sorted. If you don't get the caps right, you could tear up your crank. You may have to get them reconditioned and they'll make em round again. I would risk guessing.

ede...I think he is saying that he does not know which cap goes with what rod. Correct bocci50?

 

if you do have the caps and rods mixed i'd just take them to a shop and have them all sized, or checked.

 

if you know which cap goes son which rod, then all you hahve to do is put the tangs together. In both the rod and the cap, they should go on the side away from the cam.

If you mixed the caps up, you could first check all the microsscopic markings that they left on each other, and match as many as possible up that way; then try the rest one at a time until you find ones that result in a perfectly round bearing bore (same diameter in 2 measurements 90 degrees apart, and no detectable overhang where they meet; if you can't get them matched those ways, it's time to get them re-conditioned.

Buy a set of number stamps and stamp them first next time, before you take them off the crank. Don't do it after, you'll probably end up bending the rods without the crank to support them.

 

Thanks for your replys and advice.

I do have the pistons and caps numbered, so I do
know which goes to which cylinder.
I just didn't have the foresight to mark which direction
the caps should go. I know that one side has a
number 58 on the caps.

Saturday I started putting in the bearings and the Crankshaft.
The crank was supposed to be turned and I got some bearings
at .010 to reflect the difference. Well after I torqued everything down, the crank wouldn't turn at all. So I need to bring it back to the machine shop and have them check the tolerances.

Then to add insult to injury a couple of my piston rings were broke right from the box.

I'm going to give it another try this Saturday.