Slowverado

what do you hardcore guys think are better, the Eagle "H" beam 6.125" rods, or the pro billet 6.125" rods?

how do you use a 6.125" rod with a stock crank if the stock rod is 6.1? wouldn't that cause a proble, or is it compensated in the aftermarket pistons with a shorter deck height or something like that.

Nasty N8

iTrader: (33)

The pro billet rods are better than the eagles. You can go as big as 6.200 rods and it is compensated in the pistons you will need to let the piston maker know what rod and stroke you are using.
Nate

Slowverado

thanks man, so, if i order the pro biller rods i would just have to tell the represenative at DIAMOND or ROSS that i'm running the 6.2" Lunati rods and he will know what to do to compensate? what is best to run with a stock crank, 6.1/6.125/6.2" rod???? i don't understand the difference in the three different combos and what makes one better than any of the others.

FDLS6

iTrader: (4)

I'm putting my ls6 together with 6.3" la enterprises kryptonite rods. The idea with the longer rods, is that is reduces rod angularity, helping decrease the piston/cylinder wear. Also, the longer rod increases dwell over TDC, allowing you to harness a little more of the combustion energy. The downsides are, if you go with too long of rod, the compression height of the piston becomes very short, which can cause problems including placing the pin up in the oil control ring, and/or minimal space between the face of the piston and the top ring. As far as making the combination work, you need to do the math. (.5*stroke)+rod length+piston compression height=9.24"
if you have a stock stroke (3.62) +6.1" rod, you need a piston with a compression height of 1.33"
with 6.125 rod, you need a piston with a compression height of 1.305"
with a 6.2" rod, you need a piston with a compression height of 1.23"
for my 6.3 rods, my piston is 1.13"
These figures are for a 0 deck height, which is fine for .040 cometic's. if you use the .05 ish stock gaskets, you may want to increase your compression height +.01 so your pistons are 10 though out of the hole to get 40 though quench height. hope this helps
Bryan

Slowverado

Bryan, what pistons do you have? i have a set of Ross 4.030 pistons that were designed for the 4.125" stroke 6.2"(?) rod combo...basically i'm wondering if they'll work for my stock stroke crank if i just get longer rods. lunati told me a while back that i could with a custom rod, but i'm not sure how to figure all that out. and where do you measure to find compression height?

FDLS6

iTrader: (4)

It sounds like your pistons are not really going to be a good choice. First, I assume you have an iron block, or a resleeved aluminum block(to accomidate the 4.030 bore). with a stock stroke, you would need 6.45 or 6.46" rods to make a piston that is for a 4.125 stroke, 6.2" rod work. If your pistons are indeed setup for 4.125 stroke, 6.2 rod, the compression height would be .978 to .980" that's very short. I think you would have to pay big bucks to have a custom rod made to work with those. the compression height is measured form the center of the pin hole in the piston, to the face, or top of the piston. it would probably be cheaper to get some standard sbc 6.125 or 6.2 rods, buy some je's or diamonds, and sell your ross's. I have lunati pistons from lingenfelters stroker package.. they were for a 4" stroke, and 6.125 rod.. they work out perfectly with the 6.3 rods I have and stock stroke. it jsut worked out that I found that combo of parts at a good price when i was putting everything together...

Slowverado

that's what i figured(the ross' were junk to me) but i was hoping i was wrong. guess they're for sale again....any takers?

FDLS6

iTrader: (4)

well, don't give them away for too cheap.. they'd be great for someone doing an iron block stroker.. just not ideal for a stock bore and stroke setup.. (now, if they were form a small block chevy, they are no good for an ls1 in any shape or size, because the valve angles and position are much differrent) good luck to you

Slowverado

thanks for your help man.

Vents

iTrader: (9)

FD, good info. if i'd known i could have used a 6.3" rod, i'd have gone that route. my pistions were custom from diamond anyway, and it hadnt even crossed my mind. i'd much rather of had a 1.73:1 rod angle than a 1.69. but oh well, live and learn i guess.

back to your question matt, the eagles are a little more readily available, cheaper, and i think for what you're doing a better idea. the pro billets are good for more HP, but are you really going to spray 400 + ? save some money unless you just have to have that extra peace of mind or just have money growing on trees.