1bad2k2ta

iTrader: (3)

MAJOR FYI <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

I am going to be building a 382 stroker for forced induction. I am in the process of purchasing a set of Lunati -8cc dish pistons and 4" stroker crank from other individuals on this board.

I started looking for rods that would work with this combo. Since I am already out some serious cash, I was looking to go with a less expensive forged SBC 6.125 rod since that is the correct length for the Lunati rotating assembly and I had heard that the 6.1 rods are interchangeable with the LS1 and LS6; NOT SO.

I talked with a well known tech at one of this boards sponsors and he explained that the small block Chevy 6.125 and 6.1 rods can be used as long as they are for a 2.1 rod journal and you have them machined to correct for the difference in offset. If you do not have them corrected, they will work but the piston will not be perfectly centered in the bore and one side of the cylinder and piston will wear faster due to side loading. He went on to say that for peace of mind I would be better off spending the bucks for the Lunati Pro Billet rods that are designed for that assembly.

This made me curious, so I called Lunati and they confirmed in detail what I had been told <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" /> .

BEWARE: A lot of the engine builders out there are either not aware of this or they don't consider the difference in offset to be significant. Ultimately, side loading will increase internal friction and wear and cost you horsepower and more money than if you went with the correct piston in the first place.

Sorry so long, but I think this may catch a lot of you by surprise as it did me. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

theblur98ss

iTrader: (71)

I think lunati offers a rod that's a few hundred cheaper then there pro billets.

Ryan K

iTrader: (11)

Ok, explain this a little more. Where is this "offset" you speak of? are you talking center of pistons front to back or top to bottom?

Ryan K.

NoGo

iTrader: (2)

He is talking about the centerline offset.

On a SBC the crank is not perfectly centered between the piston bores. There is an offset (.006 I think, but am not sure). Because of this, the rods need to be offset as well to maintain perfect geometry.

The LS1/LS6 block has a centered crank, and thus connecting rods with zero offset.

Putting in a set of SBC rods isn't going to cause your engine to spontaneously explode. Don't get me wrong, I wouldn't recommend it for a motor that you expect to get 100,000 miles out of.

But for most drag races pilling their car with 300+ nitrous, this is the perfect substitute.

Ryan K

iTrader: (11)

Thats what I was thinking.

Ryan K.

rodent

iTrader: (1)

I just purchased a set of Eagle H beam rods for the LS1 part # CRS6100L3D, stock length 6.1". I assume these are correct for the engine. I was really close to getting the SBC rods, now I'm glad I didn't.

BTW- I paid $480 for the LS1 rods which I didn't think was too bad.

ibjamin

iTrader: (6)

You can get the Lunati pro mod rods for $699 from Thunder racing and various other vendors. I know a speed shop that had the Lunati Pro billet rods for $865. E-mail me and I can give you the name and you can call and see if he has any left.

George

Nasty N8

iTrader: (33)

Eagle does make a good inexpensive set of rods that will work. They have to be LS1 rods not SBC rods the crank journal is larger than that of a SBC.

Nate

Paul F

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Nasty N8:
<strong> Eagle does make a good inexpensive set of rods that will work. They have to be LS1 rods not SBC rods the crank journal is larger than that of a SBC.

Nate </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry Nate but you are incorrect. Both LS1 and SBC are a 2.100. SBC rods will work fine in an LS1, assuming everything else is correct for the given length.


Paul

1bad2k2ta

iTrader: (3)

I have been calling a lot of machine shops and other motorsports shops to try and determine how much needs to be shaved off the offset to get the piston centerline correct, but most don't even know what I am talking about and the ones that know what I'm taling about don't have a clue as to how much needs to be removed. One prominent engine builder on this board said they use small block chevy rods in almost every engine they build with no issues. I asked how many he had out there with 100,000 miles on them and he said he has never seen any LS1 make it to 100,000 miles because the bearings, etc. wear out way before then. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

I would agree with NoGo; if you are planning on rebuilding your engine regularly (every few years) then this probably is of no concern. I am building an all forged bottom end that should be good to 1250+ horsepower that I plan to only run a max of 700 or so rwhp on, but I want it to last. I only want to do this once.

I am not trying to alarm anyone, I just want everyone to be aware of the issues so they can make an informed decision when they tear into their bottom end. It is a costly endeavor and it only makes sense to do it right the first time IMO. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />