Rods....I or H beam?
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Joined: Dec 2003
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From: NORCAL
Rods....I or H beam?
What are the differences? Advantages/Disadvantages?
I've always seem different I or H beam rods listed...but never actually understood what applications they were good for.
Thanks guys.
I've always seem different I or H beam rods listed...but never actually understood what applications they were good for.
Thanks guys.
Honda-Tech Member
Joined: Jul 2004
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From: God's Waiting Room, FL
Re: Rods....I or H beam? (EdBoon)
The construction of an H-Beam rod is stronger, most companies like Eagle or Crower design H-Beam rods mostly for turbo or any type of forced induction applications. I-Beam rods are strong but nothing like H-Beam, I-Beams are more for like an All Motor application, I would check out http://www.importbuilders.com, they have both I/H Beams for sale.
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Joined: Dec 2001
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From: assville, MI, USA
Re: Rods....I or H beam? (EdBoon)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">
The two most common "types" of connecting rod designs are the I beam and H beam configurations.
The I and H refer to the shape of the beam of the rod when viewed from the end.
The beam is the portion which connects the crank end (big end) to the rod end (small end). Each configuration has some unique qualities, however when each is designed and manufactured properly, the differences in strength are minimal.
The I beam configuration is slightly better than the H beam when it comes to compression strength. So, under load the I beam can handle slightly more pressure before bending.
The H beam rods are stronger in the unloaded cycles and are therefore, a better choice for high rpm applications, as they don't easily break on the overlap stroke.
The weights are pretty much the same for each, so the only real differences would be slight and application driven. It's also easy to "modify" each configuration to minimize the undesirable characteristics, and once again you're back at a toss-up on the (type) to use.
Manufacturing is another area that must be addressed:
I believe that the H beam is somewhat less costly to machine than the I beam rods, so there is a slight cost advantage in this respect for the H beams.
The billet rods are machined from a block of steel to the final configuration. There is considerable machine work and scrap left over when manufacturing in this manner, so the time involved sends the price pretty high.
The forged rods are frequently made from the same materials, but the actual process is far less labor and machine time intensive. The forging dies are engineered to produce a rod, which is very close to the finished rod size and shape, so there is relatively little additional material removed.
Most folks are unaware that all metal has a grain flow just like a piece of wood. If you make something from wood, maintaining the integrity of the grain is mandatory if strength is a requirement. The same is true with metal components.
If you imagine that a block of billet has a grain flow from one end to the other and you "carve" a connecting rod from it, you now have a tremendous abundance of open ended grain, and that's not desirable for maximum strength. On the other hand, the forging process imparts a grain flow that is continuous from end to end and the machining process removes minimal material, so the grain is largely uninterrupted for the length of the rod. The preservation of the grain provides considerably more strength.
In all our comparison testing, the three rods (Crower, Carillo, and Eagle) performed almost identically in compression, stress, and fatigue. We did note when testing the Eagle components, that the rod could be made better yet, if some material were added to the rod flank (the blending of the big end to the beam) and some material could also be removed in another area without sacrificing strength.
</TD></TR></TABLE>
There is very little strength difference between the two designs.
The two most common "types" of connecting rod designs are the I beam and H beam configurations.
The I and H refer to the shape of the beam of the rod when viewed from the end.
The beam is the portion which connects the crank end (big end) to the rod end (small end). Each configuration has some unique qualities, however when each is designed and manufactured properly, the differences in strength are minimal.
The I beam configuration is slightly better than the H beam when it comes to compression strength. So, under load the I beam can handle slightly more pressure before bending.
The H beam rods are stronger in the unloaded cycles and are therefore, a better choice for high rpm applications, as they don't easily break on the overlap stroke.
The weights are pretty much the same for each, so the only real differences would be slight and application driven. It's also easy to "modify" each configuration to minimize the undesirable characteristics, and once again you're back at a toss-up on the (type) to use.
Manufacturing is another area that must be addressed:
I believe that the H beam is somewhat less costly to machine than the I beam rods, so there is a slight cost advantage in this respect for the H beams.
The billet rods are machined from a block of steel to the final configuration. There is considerable machine work and scrap left over when manufacturing in this manner, so the time involved sends the price pretty high.
The forged rods are frequently made from the same materials, but the actual process is far less labor and machine time intensive. The forging dies are engineered to produce a rod, which is very close to the finished rod size and shape, so there is relatively little additional material removed.
Most folks are unaware that all metal has a grain flow just like a piece of wood. If you make something from wood, maintaining the integrity of the grain is mandatory if strength is a requirement. The same is true with metal components.
If you imagine that a block of billet has a grain flow from one end to the other and you "carve" a connecting rod from it, you now have a tremendous abundance of open ended grain, and that's not desirable for maximum strength. On the other hand, the forging process imparts a grain flow that is continuous from end to end and the machining process removes minimal material, so the grain is largely uninterrupted for the length of the rod. The preservation of the grain provides considerably more strength.
In all our comparison testing, the three rods (Crower, Carillo, and Eagle) performed almost identically in compression, stress, and fatigue. We did note when testing the Eagle components, that the rod could be made better yet, if some material were added to the rod flank (the blending of the big end to the beam) and some material could also be removed in another area without sacrificing strength.
</TD></TR></TABLE>
There is very little strength difference between the two designs.
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