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but what I notice in comparing a H beam to an I beam is that the H beam rods are much wider in the Y axis. So, when looking just at the shape, one would think they have the same strength characteristics along the line of the web, and their strength characteristics are 90 degrees from one another. I am thinking that with the much wider width in the Y axis, the H Beam has more strength in that axis, or at least equal strength, than the I beam, yet still has strength in the X axis, and has a lighter weight than if you made a rod with the same strength in a I configuration.
Thoughts?
Yes, compare weights from otherwise identical (to the application) H beam vs I beam rods, and lighter weight = less stress on the rod bolts.
Doug
Someone please explain to me why H-Beam rods exist.
The H-Beam would make sense if the rod stress is longitudinal WRT the engine, i.e. parallel to the crank centerline.
It's not.
If there is any bending stress on the rods it is lateral (i.e. from side to side) and for that, an I-Beam is the configuration which makes the most sense.
Maybe it's a marketing breakthrough....
In the interest of full disclosure: The Eagle rods in my road race engine are H-Beam. I bought them before thinking through the stresses. Not sure I would buy H-Beam again until/unless someone shows me the error of my thinking.
Jim
H-beam rods are designed to reduce windage in wet sump applications. You can pick up 20-30 horsepower over a set of I-beams just by using the H-beams. That's why the mid-level aftermarket rods are H-beam but when you go to 4 digit horsepower levels you have to switch back to I-beams for strength.
Rex, I used the Eagle rods on Duke’s recommendation when I rebuilt the 327 in my 62 a couple years ago. Builder liked them and looked good to me but unfortunately only dyno time on the engine at this point.
I ran Carrillo rods in my road race engines. In the SVRA version of the motor it made around 600 HP and I ran it up to 9500 RPM regularly occasionally 10,000 if I needed to get by someone.. They are expensive but they were the best i could find and I never had a rod failure.I ran them for 15 years in the road race car in both dry sump and wet sump applications. I would recommend them.
If you choose an entry level brand of rods (these include most off-shore pieces) try to use ones that have the oil holes for the wrist pins BELOW the rod eye, not above it.
Talking H-beams here the Eagles we carry all have this right, oil holes on the bottoms. Scat had them this way for years also but we just learned now they stopped doing them this way and are now drilling a single hole through the tops of the eyes! These top holes are all but useless in higher HP units!
The I-beams, both Eagle and Scat, all have the top holes. Occasionally we do use these and when we do we still drill our own holes below the eyes!
(Add info) Both sides below the pins get drilled for oiling, photo below of those Crowers I mentioned here!
Thanks, Gary in N.Y.
P.S. When you get into power-added builds you MUST have the pin-oiling BELOW the rod eyes! Just went down this road recently with some higher-end Crower rods, we ended up drilling our own holes in these for a 2000+ HP unit!
Last edited by GOSFAST; 11-20-2018 at 07:24 PM.
Reason: Add info
H vs I really has no influence on weight. You can buy either in pretty much any weight you desire but mostly in higher end rods. The Cower rods Gofast has pictured are available in 5 different weights for the same rod. Years ago NASCAR ran Carillos in the 850 gram range. Then later in their never ending qwest for more everything and less everything NASCAR stepped in and said the minimum rod weight is 535 grams. They also regulate the minimum diameters on the rods and mains.
Thanks to everyone for your well educated comments. This is obviously more information than my peanut brain can digest , but is much appreciated. Perhaps I should have simplified this initially by stating that my plans are to build a strong street engine in the 550 - 600 horsepower range and it will probably never see 6500 RPM. Now, with that said, IFFFFF I were going to build a super performance engine I would definitely use top rated rods........................probably Carrillo or Oliver. However, I can't justify that expense for my project. Like I stated initially, I was seeking opinions (good or bad) from actual users of Scat and Eagle rods and I got what I was seeking......................plus a lot more which I will "put in the bank" for future use.
Thanks very much to everyone who contributed to this thread. I value and respect EVERYONE'S input and comments.
I hope everyone has a safe and enjoyable Thanksgiving. Eat plenty and be thankful.
The Carrillo’s have the cheaper or expensive bolts! For all around, these are the best! I had their Chevy rods in my Porsche! I should have kept that engine!
The next Generation has basically taken over at Crower, haven’t heard any problems yet! They have different rods, some weighted more for high rpms, and others more endurance! Everything from aluminum to billet one’s and every level of steel in between!
Scat now! Scat from them! Now foreign jobs!
I have heard Olivers were good.
Eagle know nothing about Them, except seems cheap in price!
They used to be. Their reputation has improved quite a bit in the last 10 years or so.
That's really debatable at this stage, if you read my post about the pin-oiling locations on the Scat rod eyes you see they had it correct and NOW have it wrong?
This isn't an operation that we would consider to be an "improvement" here, more like a step backwards. I'm really surprised Tom (the owner) went ahead and approved this change??
Thanks, Gary in N.Y.
P.S. Scat has other issues with getting the balancing correct on their (internal-balanced) cranks, too much labor involved, for this reason we no longer use their cranks at all. We do still use their rods, but this remains up in the air unless they make a u-turn (again) on the pin-oiling?
If it’s between Scat and Eagle, keep in mind that the Eagle I beams are 5140 steel. The Scat’s are 4340.
Not exactly "true", we stock Eagle "4340" I-beam rods, both SBC & BBC, have been for years now!
These rods are "rated" to be able to handle 750 HP (SBC's) and 850 HP (BBC's) with no issues?? However, we still don't like the pin-oiling in these I-beam rods either, but it's something we are able to "fix" here on our own!
Thanks, Gary in N.Y.
P.S. We feel it's nicer to actually have the choice of 5140 OR 4340 I-beams, we can pick & choose where we need to pertinent to the build, the 5140's are a couple dollars less.
Thanks to everyone for your well educated comments. This is obviously more information than my peanut brain can digest , but is much appreciated. Perhaps I should have simplified this initially by stating that my plans are to build a strong street engine in the 550 - 600 horsepower range and it will probably never see 6500 RPM. Now, with that said, IFFFFF I were going to build a super performance engine I would definitely use top rated rods........................probably Carrillo or Oliver. However, I can't justify that expense for my project. Like I stated initially, I was seeking opinions (good or bad) from actual users of Scat and Eagle rods and I got what I was seeking......................plus a lot more which I will "put in the bank" for future use.
Thanks very much to everyone who contributed to this thread. I value and respect EVERYONE'S input and comments.
I hope everyone has a safe and enjoyable Thanksgiving. Eat plenty and be thankful.
Rex
Buy some Crower steel full floating rods. You get a much better price buying direct from them as compared to what the catalogue price is.
Doug
Not exactly "true", we stock Eagle "4340" I-beam rods, both SBC & BBC, have been for years now!
These rods are "rated" to be able to handle 750 HP (SBC's) and 850 HP (BBC's) with no issues?? However, we still don't like the pin-oiling in these I-beam rods either, but it's something we are able to "fix" here on our own!
Thanks, Gary in N.Y.
P.S. We feel it's nicer to actually have the choice of 5140 OR 4340 I-beams, we can pick & choose where we need to pertinent to the build, the 5140's are a couple dollars less.
Do you know how the weight compares between the Eagles and the Scats?
as to drilling oiling holes from the bottom of the wrist pin bore I saw pictures at GM where the wrist pin split the rod thru those bottom oil feed holes. these were stock BB chevy rods.
11-20-2018, 04:03 PM
, but is much appreciated. Perhaps I should have simplified this initially by stating that my plans are to build a strong street engine in the 550 - 600 horsepower range and it will probably never see 6500 RPM. Now, with that said, IFFFFF I were going to build a super performance engine I would definitely use top rated rods........................probably Carrillo or Oliver. However, I can't justify that expense for my project. Like I stated initially, I was seeking opinions (good or bad) from actual users of Scat and Eagle rods and I got what I was seeking......................plus a lot more which I will "put in the bank" for future use.
