What are the correct uses Of "I" beam and "H" beam rods?

[LowBuckX]

So what are the correct uses for "I" and "H" beam rods?
What are the trade offs for one over the other?


*****EDIT******
Yes I do know the physical differances.

[LowBuckX]

found One answer on the web


H-Beam Vs. I-Beam




For years the battle has raged on as to which is better, an I-beam or an H-beam. In pure tension and compression, they are both equally capable, assuming equal cross-sectional area. But when you add the fact that some components of the combustion event attempt to screw the piston down the cylinder, the greater distance from the centerline of the pin to the edge of the beam gives the H-beam an advantage in resisting such twisting forces. We’ve seen both designs used successfully in a wide variety of extreme applications, so the jury is still out. Perhaps the biggest advantage of the H-beam design is that it gives the manufacturer more flexibility when sculpting the rod into the most effective form from a strength-to-mass standpoint.

[yody]

hmmm, for some reason I feel like I should know this, but honestly I don't but always wondered the same thing. I do know that a lot of the guys like Oliver and such only offer I beams for High HP applications, I think cam/oil pan rail clearance is also a factor. If I was desigining a motor, I think weight would be a big factor in my choice. Good question, Call Carillo or Oliver, I bet they would have a good answer

[Lowend]

Truth me told the shape really dosen't matter... its more materials and QC than anything.
The top of the line Olivers are H-beam. the Top of the line Crowers are I-beam
Both are stronger than any street motor would ever need

[SStrokerAce]

In a low buck sense a I beam vs. H beam the H beam is the better rod. Mostly because the rod is a fully machined forging that is shot peened after machining. While the I beams are raw forgings with design improvements over stock rods (better material, bushed pin bores, cap screw bolts etc...) but they are basically a copy of a stock connecting rod.

A low cost I beam like a Scat I beam is a good rod that can take some abuse if prepped and installed properly. 500hp and high 6000rpm range should be the limit for them, and I'd keep them in a NA engine as well.

A H beam would be the next step, Eagle, Scat, Manley, Lunati all make nice versions. Again the prep and installation are the keys to making them live. With good rod bolts these rods can take a hell of a beating.

Next step after this would be Oliver, Carrillo, Arrow etc... these rods differ in design but are also usually in the $1000+ range for a set. Unless you are a professional engine builder or planing to make well over 1000hp or spin 8000rpm plus I wouldn't worry about them since they are usually a bad place to spend money in a budget limited street engine. Not that they aren't awesome quality, the money can be spent elsewhere and give the consumer more benefit in durability and HP.

Bret

[bigblockcapri]

how about these rods
got them in my truck
http://pauter.com/

[SStrokerAce]

how about these rods
got them in my truck
http://pauter.com/

Yeah they make some nice stuff too.

[curt70]

In a low buck sense a I beam vs. H beam the H beam is the better rod. Mostly because the rod is a fully machined forging that is shot peened after machining.

Wrong when you cut into the grain stricture of the material that is where you weaken the rod a forged rod with the least amount of machining will be best. H style rods work because of their mass. The main stress on a rod goes down the thick on the side of the I beam
curt

[SStrokerAce]

Curt,

Interesting thoughts.... maybe you should go to PRI and inform every rod manufacture in the world about this then.

The point of a fully machined forging is that you form the grain structure into the shape of the rod then machine off the top layer of the forging where the most impurities are, since forging is a dirty process. For cost reasons you machine the least amount of material, for strength reasons to make the forging larger and machine more material off the connecting rod. Not to mention that this reduces stress risers, and then when it's all said and done the machined blank is shot peened to add a compressive stress to the part.

If not machinging a forging was the right thing to do then all the prep that was done 15+ years ago to "pink" GM rods was actually hurting them. If you don't know the prep was to remove the balance pads, and profile and smooth the beams of the rods in the direction of beam to reduce stress risers. Hell now Scat even produces a prepped low cost I beam rod with larger bolts and polished beams.

My comment about "low buck" rods compares something like a Scat I beam ($250) to a Eagle H beam ($350-400) to each other. It's not comparing the strengths of the I vs. H beam design. One is a copy of a stock rod and the other is a copy of the most famous high performance rods made (Carrillo)

Bret

[Damn True]

"I" before "E" except after "C".

That's all I can tell ya.

[SStrokerAce]

lol, thanks.... I should take a better look at my writing.