Stupid LS1 assembly question

[derekf]

Started assembling my engine today.

Found something .. odd, and by "odd" I'm not referring to the way that the #5 and #6 pistons had been put in the wrong holes.

There's a little dot on the pistons, that I believe notes which side of the piston should face the front of the engine.

There's also a bevel on one side of the big-end of the rod, which I believe should be put towards the fillet on the crank.

Also on my particular engine, there's dents in the pistons where the valves have impacted.

If I assemble the engine such that the dents are towards the top edge of the pistons on both sides, and the dots are towards the front on both sides, then the beveled edge of the big-end of the rods are not facing the fillets. If I put the bevels right, then the dots are facing the back of the engine and the dents are not where the valves would have hit.

This tells me that the engine was run and driven hard with half the rods backward, or I'm an idiot.

Am I a moron, or should the rods be set such that the bevels line up with the fillets (ok, so I may not be using the correct terminology)? And if the bevels need to line up, will it create a problem that the dots are now facing the back of the engine - do I need to take those four pistons out and take them up to the machine shop to have them turned around on the rods?

[yody]

Well I have no experiecne with LS1 motors whatsoever, but i am 99% sure that the bevel goes towards the crank fillet, of course theres always that 1% LOL. You are a smart man for asking this question, I am sure the info is out there. Also the dot towards the front and dents on the top all sound correc too me also. I'm sure someone has an answer?
EDIT;
man this motor just sounds like it was put together half... backwards. Good thing you opened it up!

[paul67]

I have in front of me a 1991 GM corvette service manual, this is whats written.
1, piston rings Install
Top ring should installed with indent facing down,second ring should be installed with mark (top) facing upward, rings should be installed with gaps facing approx 120deg apart.
IMPORTANT, Rods must be installed pistons with the arrow of the piston facing the front of the engine and the chamfer on the journal end of rod facing the crankshaft counterweight.
. Rod chamfers face to front on LEFT bank
.Rod chamfer face to rear on the RIGHT bank
Also Large chamfers on connecting rods must facecrankshaft counterweights,
This is for a LT5 hope its of some help
paul67

[derekf]

Yeah. That's what I thought; thanks, y'all.

Followup question: If I've put the rods so that the chamfer and the fillet line up, is there any problem with the dot being on the wrong side of the piston - are the pistons symmetrical or is there a reason to have the pistons turned on the rods?

[paul67]

I think the safe thing to do is to go to the local GM dealer and get the GM service book for about $90 it will prob pay for it self real quick.
paul67

[derekf]

I've already got it (it was actually 135), but it doesn't really go into whether the pistons can be used backward since that's not really a concern with stock GM.