C4VetteLS1

People keep saying the offset on a ls1 rod is different and a standard sbc rod isnt usable. ive talked to chris @ diamond about it and you just use any SBC 6.125" Rod with a piston made for it. Ive never heard this before and ive seen tons of motors together with standard SBC rods with no problem.


But people swear its going to sideload the piston and wear it faster?? I dont think this is true in anyway.

Myth or fact?

Cal

iTrader: (1)

It would put more of a sideload on the wrist pin than on the piston. Apparently the SBC rods work because the offset is small, but it would be better to use LS1 rods IMO.

Pro Stock John

iTrader: (34)

I am running a 6.125 Eagle rods with a stock crank there are many cars out there with a setup like this.

frcefed98

iTrader: (16)

I have SBC rods too, Eagle SBC 6.125 rods with Diamond -8.6cc blower pistons and stock crank.
J

PSJ thanks for the help on the fitting for my F/P gauge

Country Boy

iTrader: (24)

But to all those running a SBC rod, are the rods centered on the pin? The crank journals and bores are made to use a LS1 centered rod to center the rod on the pin. A rod to one side or the other will wear the pin/ piston. You can use them, yes, but I bet the motor doesnt last as long as a centered rod/ pin setup.

When I put my motor together, I had the SBC big end rods, I put them in different ways untill I had the rod the most centered on the wrist pin. That made the rod not the tradional SBC style on the crank, but I had the chamfer side (the offset) to the flat side of the neighbor rod. This is where I thought my oil pressure problems were from untill I pulled the crank. The LS1 has a centered rod for a reason... Ill post a pic of my bottom end when I resize it.

Country Boy

iTrader: (24)

Heres a pic, look at the red line I put to seperate the rods. You can see all the chamfers face to the left and you can see the offset on the rods. No look at the pins. You can see some reaaly good offsets, now if I turned the right rod on each journal around, the rod almost contacts the piston.

taqwache

i see what you are saying carl but i dont think that it will make that much of a differents. if it was a serious problem then someone would of said a long time ago. i am useing a 6.125" scat rod with a 2.00" big end on it. i cant use a LS1 rod since nobody makes one in this big end size. once the motor was built, i did notice that the rod side clearance on all of the rods was .022 which is .002 bigger then what GM reqamends. i should be ok though.

2001CamaroGuy

iTrader: (6)

can't you get bearings that are a little wider to make up the gap?

2001CamaroGuy

iTrader: (6)

what turned out to be the oil pressure problem?

Country Boy

iTrader: (24)

The line hone was out on my block causing one of the mains to be off center. Heres the pic.

2001CamaroGuy

iTrader: (6)

ohhh....thats nice.....


So then do you see any problem with setting up SBC rods in an LS1 like you did? If they are turned around so they come out centered (or very close to), there should not be any problems (correct?).

AP-Engineering

Guy's you are able to use SBC rods in LS1's. The difference in the two rods is the SBC is offset .060" on the big end of the rod to center it in the bore of the SBC's. LS1 rods are on center, they require no offset in the rods to center them in the bore. Running a SBC rod in a LS1 will offset the rod on the wrist pin, this for most people will not be a problem. In higher HP applications, you should try to use a LS1 specific rod to eliminate the side loading of the pin which will occur with the SBC rods. On a every day driver this will cause no problem, even for moderate performance LS1 engines the SBC rods have worked just fine.

Chris

P.S.
You can't turn around the SBC rods and run them. You will have no side clearance and that is no good.

Paul F

iTrader: (2)

Chris is 100% correct. We've used SBC rods in most of the motors that's we've built with NO problems


PS: Chris (BM) you'd better start saving your money.

Country Boy

iTrader: (24)

Thank you Chris. People are probably starting to think I talking from my a$$ Actually, you can run them on a stock crank turned around because the stock crank has little to no fillet on the rod journals like a SBC does. Thats what the chamfer on the rods and bearings are made to clear.

AP-Engineering

Country Boy, on a stock crank you are probably right. Without the fillets you probably are able to get them to turn around and run. Not sure if I would though. Something seems wrong about that.

Paul, My money is saved up, but none of it will be coming your way after the first. I think that you will be sending me something though! GO BLUE!

Country Boy

iTrader: (24)

I didnt see any problems in my motor, but Im not telling you to go do it either. You can do it on a STOCK crank because of no/ very little fillets on the rod journal. The way I had them in was the only way I could get the pins closest to center as possible. With them SBC style on the journals, the pins were VERY offset.

AP-Engineering

Ya the stock cranks have no fillets, they are under cut on the edges where the fillets usually are. So this is why you are able to turn them around.

Paul F

iTrader: (2)

2001CamaroGuy

iTrader: (6)

yay....I just got off the phone with Jason and this was one of the many things I mentioned to him.

His feeling was for the average person who is looking for ~50-60K miles out of their motor and does not want to spend loads of money, SBC rods will work fine. If you are pushing high HP numbers and/or want 100+K miles, look into "true" LS1 rods. He also mentioned that the Lunati Pro Mod rods that they sell are a SBC style.


Thanks Jason....I feel MUCH better about where I'm going with my motor now

Jason99T/A

iTrader: (21)

No problem Chris. Glad I could be of some assistance. Good luck on your build-up.