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I beam versus H beam rods

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I beam versus H beam rods

Postby Drew » Sun Feb 10, 2008 3:00 pm

I'm having a 383 built that will put out somewhere around 525hp and was wondering which rods to use either Scat I beam 2icr with the 7/16" capscrews or should I go with Scat H beam rods for this power level. Thanks
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Postby David Redszus » Sun Feb 10, 2008 3:28 pm

Providing the rod cross sectional areas are the same, and the material used is the same, there will be no difference in rod strength in tension or compression.

If, however, the rod is subject to bending forces, then the orientation of the I or H beam becomes an issue. Which way is your rod bending?
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Postby black_z » Sun Feb 10, 2008 3:30 pm

I have always wondered about the differences (pros/cons) of I vs H beams.
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Postby fishman » Sun Feb 10, 2008 4:30 pm

i use the scat 60 i beam rods with 7/16 cap screws they r rated to 750 hp and they are less moving mass so in my case like yours it would be worth running them......just my opinion
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rods

Postby Drew » Sun Feb 10, 2008 6:10 pm

Thats exactly my thinking. Looks like anywhere from 25 to 50 grams lighter per rod.
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Rods

Postby bigjoe1 » Mon Feb 11, 2008 12:05 am

I always use the I beam rods in everything I build, In high HP engines, I use the 7/16 bolts. That works out very well.

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Postby Wolfplace » Mon Feb 11, 2008 12:39 am

Another plus is that rod will have a ton of cam clearance, way more than even a stock 400 rod

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Re: Rods

Postby TORQUE INC » Mon Feb 11, 2008 1:57 am

bigjoe1 wrote:I always use the I beam rods in everything I build, In high HP engines, I use the 7/16 bolts. That works out very well.

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Hey there Joe

What brand of I beam rods do you prefer ?

Just curious

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Postby Stef » Mon Feb 11, 2008 4:02 am

For N/A engines there is a weight advantage using I-Beam rods. H-Beam are good for high compressive (buckling) loading i.e turbo or supercharged engines. Can't pull as much weight out of them though.
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Postby TORQUE INC » Mon Feb 11, 2008 4:09 am

Steff

I know the difference and I use both styles of rods

Was just wondering what Big Joe used and why.

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I beam rods

Postby bigjoe1 » Mon Feb 11, 2008 11:13 am

I do use the SCAT I beams rods about 90 percent of the time. They are made to clear the camshaft better than any of the others out there. I do still grind the rod where the threads of the bolt come through on long strokesThe machine work they do on the rod saves lots of time when you go to assemble the engine. I have only had ONE failure and that waas with a 3/8 bolt iinstead of the 7/16 bolts.

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Postby thundair » Mon Feb 11, 2008 12:07 pm

Maybe some will chime in as to what forces and at what direction is it that brakes the rod.

I had the privilege of spending some time with Jack Sparks @ Carrillo and we had this same discussion. It seems inclusions in the metal cause growth or collapse upsetting the symmetry of the rod, that misaligns the crank axis with the wrist pin axis and starts a failure in work.

IMHO a rod body should be a hollow tube still giving the compression and tinsel strength but adding torsional strength for the same weight rod.

I would like to know what the Pros think
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Postby curl'd » Mon Feb 11, 2008 5:33 pm

Stef wrote:H-Beam are good for high compressive (buckling) loading i.e turbo or supercharged engines. Can't pull as much weight out of them though.


You might want to double check that. :wink:
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Postby af2 » Mon Feb 11, 2008 5:50 pm

curl'd wrote:
Stef wrote:H-Beam are good for high compressive (buckling) loading i.e turbo or supercharged engines. Can't pull as much weight out of them though.


You might want to double check that. :wink:



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Postby 2xmod » Mon Feb 11, 2008 8:21 pm

I have 3 seasons dirt track racing on a set of scat 60 i beam with 7/16 cap screws. They are in a 13:1 6 inch 355. I turn in 7800 all the time. Thats almost unbelievable for a $250 set of rods. :shock:
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