I have found an Eagle rod that is listed as a SBC 6.125" with .927 wrist pin and 2.100 main journal. I was curious as weather it would work in an LS1. The name of the rod is an Eagle SIR Lightweight. I am doing a budget build up and the price of this rod is just about right. I dont plan on boosting this motor but maybe a little 100 shot.

I have heard that the LS1 rods are centered and SBC rods have an offset. Is this true because I have heard that the LS1 rods do and do not have an offset. Im not near a rod to check it out. Maybe some of experienced LS1 builders can clear this up for me. I remember when I reassembled my motor from before all of the rods had to face toward the front of the block.

So do the rods have an offset to them or not.

 

I thought that the pistons had the offset or the crank. I mean how can the rod be offset its straight? or maybe im way off. See what I mean? But I have too also hear there is an offset on the sbc

 

You are right piston is what has offset not crank or rods.
Offset ground cranks are when rod journals are reduced to gain stroke in grinding process, totally different thing.

 

Here's my take.......

The Eagle SIR Rod has:

Forged from 5140 steel "SIR" rods offer 50% greater strength than the GM "Pink" rod.
"Sir" Lightweight Connecting Rods Feature:
* New Forged 5140 Steel Rod
*ARP Wav Lok 3/8 rod bolts with 12pt.nuts
*Each forging is x-rayed,sonic tested & magnafluxed to insure quality
*Shot peened to stress relieve the metal
*Packaged in weight matched sets +/- 2grams

"The perfect choice for Pro Street, IMCA and classes that require a stock appearing rod."

Large Journal 2.100" Crank Pin

It's a better rod than stock but it's not going to fit easily. The big end width is .940 while the LS1 is .945, which means you will be running to much rod side clearance. But people seem to do that here.

If it was me I'd rather run a 4340 Forged rod like the Scat I beams, but they don't come in a 6.125" length. Those Eagle SIR rods are the only Cheap choice to run. If you wanted to spend more, like $400-$600 then there are alot of rods out there that you are not going to overpower.

Bret

 

Ok here is the real deal.

LS1 rods are centered, for example, if you set the LS1 rod flat on a table (you see two circles when looking down on it) if you cut it horizontally in half the two haves would be similar. If you did the same to a small block chevy rod, one half would have more of the rod. This it is off set front to back.

If you go with an aftermarket rod, you are going to an aftermarket piston, unless you get a direct replacement LS1 rod. Small end clearence is not an issue side to side, the piston needs to be able to move.

As far as offset pistons, they are totally different, when you are taking about piston offset, you are talking about where the pin is sitting. Either the pin is in the center of the piston or it is moved out tword the upper or lower skirt.

Long story short, The Eagle rods will work as long as you get the pistons made for the rods.

Ryan K.

 

Ryan, thats what I was thinking, because I thought about it later and that was probally the thing that was offset. Thanks for the info

 

Those rods will work, however you will need a custom piston since its .025" longer then stock and requires a floating wrist pin (piston). Stock rods are press fit and 6.100" in length. Don't forget to get it balanced again. If you need pistons/rings to go with those rods, call ARE, I can get you the right setup. BTW, the bores are offset in an engine, not the rods.

 

but there is nothing "special" about buying pistons for these rods right?

I just buy "some" forged piston with a 0.927" pin and the correct compression height to go with the crank and length of rod.....or is there something "special" that I need to tell the piston company?

I had planed on ordering the rods from Summit (cheapest place) and the pistons from TR (good company to do business with).....I figured I would tell them the rod length, bore, stroke, and pin size so they could get me an off the shelf piston......

 

SStrockerAce can you give me some ideas of some rods that are in the $400 or so price range that have the B.E. width that is equal to stock width? I was also looking at the Eagle 6.125 H beams but the also have the same B.E. width of .940 and alot of sponsers sell these rods. Also the Crower Sportsman rods from SDPC also have a .941 BE width. So are these rods ok to use even though the stock BE width is .945? Why are they selling these rods if they are not the correct width?

The offset I was talking about was exactly how Ryan Karasek explained it. That is what I was wondering about if the rod has more meat from front to back. So would it be more wise to go with the H beams since they are the same on both sides?

 

TTT for anyone that may be able to answer my question.

 

The "offset" that you are asking about in an LS1 engine is specific to the PISTON. Long story short, the pin is offset from the center of the piston, and because of this, you must pay attention when installing them so that you put the correct side to the front.

 

Small Block Chevy Rods have a side to side difference because the large side (to make this simple) has more clearance for a big radiused fillet. Meaning that there is a 90 deg cruve going from the counterweight on the crank to the rod journal. Now on a LS1 stock crank they have a cut back corner there rather than a radiused fillet. Which means that the rods don't need a big and small side for that crank. You still need to put the big side to the counter weight instead of them facing each other but they will work. All you will have is a little more clearance side to side. On a side not here the LS1 crank has a 270deg radius rather than a 90deg radius. It's a VERY GOOD stock design. That crank as we know is very strong, and I would say that it's the strongest production non forged crankshaft for it's size ever made! I've been seriously impressed in what I have found out about it.

If it was me, I would get a Eagle or Scat H beam for a SBC and get the pistons to match. Check out the Price of a Scat H beam in 6.125,6.200 and 6.250" lenghts, for the extra bucks I would upgrade the rod bolts. THAT IS ALWAYS A GREAT IDEA. You can find the Scat H beams for under $400 and the rod bolt upgrade is $100 normally.

One thing people haven't noticed is that you can tell a piston and a rod setup for a LS1 vs a SBC by the piston pin size! The piston pin for a LS1 is .945 while a SBC is .927, so if you are going to use a SBC rod, get a piston with .927 pins!

The odd thing is that the Eagle LS1 rod has a .927 small end for the pin and a .940 big end width. It's basically a overpriced SBC rod in a weird length. Stick with the 6.125" SBC rods.

BTW My rod choice for a NA Forged 346 LS1 would be a little more expensive & lighter but not to far off what I've mentioned here.

Bret