i currently have the lunati pro mod rods in my stroker and know that i need to upgrade as i am currently pushing the limits of those rods as it is, they are recommended to 750flywheel hp, i am pushing that at the rearwheels. i have heard the eagle h beam rods are pretty indestructible.

i am open to any and all opinions and experiences.......

thanks, i am just thinking ahead for when i go through the motor possibly this winter or next.

 

FWIW the setup i am trying to purchase (high hp n/a) had Lunati Pro Mod rods and were swapped out in favor of a set of Carrillos.

 

I know George Baxter was using the Oliver Billet rods at 1,125flywheel HP in his LT1. He replaced the Oliver Forged with the Billets at about 825HP, because it was obvious the Forged were reaching their limit.

 

FWIW...i think the pro mod rods will do just fine for you...how high are you spinning them and how heavy of a piston are you using?

As long as you change the rod bolts i'd say every 2 seasons at the minimum you probably wont break them

That is just my opinion but unless the car just sees track duty and spends 90% of the time @ 6000-8000rpm i dont think you'll hurt them anytime soon

 

I have eagle h-beam and I dont know how much they can hold.. never heard any horror stories with them though... rskrause using the the pro mod rods with 733rwhp with no problems...

I thought forged was stronger than billet???

anyhow.. I think supras TT are billet... but they change to forged internals when pushing 800rwhp.

 

I wouldn't agree that Eagle H-beams are an upgrade from the Pro Mods. The Pro Mods are an excellent mid-price rod. I am in the same hp range as you are and am using them, but my setup is relatively low rev. I was going to upgrade this year, but the rods looked in such good shape I decided to keep them with some new bolts.

The next step up in my mind would be Oliver billets, ~$1,200/set.

Rich Krause

 

The Eagle H Beams are rated @ 700hp with good connecting rod bolts, which most people don't ever go for. The Eagle H's are a good low price rod and they have alot of options with them, but they are not very light, but for that strength they are normal weight.

I would say that the Lunati Pro Mods are a upgrade from the Eagle H Beams, not the other way around. On the other hand I don't think that Pro Mods are the strongest setup out there. Forged small block chevy rods (same as LT1) all stop at about the 750hp limit. (which you have to understand is a cirlce track constant high rpm limit.)

For example here is a list of some of the good forged connecting rods in the order that I like them.

Howard's Sport Rods
Lunati Pro Mods
Eagle H Beams

If you look at our GP going on, yes I am offering the Howard's in the GP but that is not why they are my first choice. They are first because the rods are very strong, less expensive than a Lunati Pro Mod and will fit in a stock oil pan unlike the Eagle H Beam. On top of that the Eagle's have to be upgraded to to the ARP 2000 series rod bolts to even be compared here. When you look at it that way, list on a Howard's is $550, Eagle H with ARP 2000 Bolts is $550 and Lunati Pro Mods are $690. That right there shows why the order is what it is.

Going up from that level is billet rod land. Now most guys never even look at these rods or hear about them because they don't make really big HP. Guys like Rich and Mindgame have, and if you see the RWHP numbers they make it's obvious why. (other than they are both smart cats)

There are alot of good choices up here. Oliver Billets, Crower Billets (Maxi Lite 93 Series), Arrow, Carrillo Billets and I'd through the Lunati Pro Billets in there too. These rods are the ones that engine builders get excited about, like street guys do about the forged rods above.

When you are looking at billet rods, price is not the first thing you should look at because if you are buying them, then you need them. All of those choices start out at $1200 list, with the Lunati's being the cheapest, but they are also not my first choice.

Now in most Winston Cup (Nextel) engines you are going find these names, but with the rods made out of more exotic materials like VAR 300M, which Carillo, Arrow, Crower (Maxi Lite 94 series), Manley and Oliver make. These are when you get into $2000+ sets of rods and they have to be made of steel. They are about 850+hp rods but weight in at 525g or lighter, but 525g is the WC weight minimum, which is crazy light and strong.

Next step is Titanium rods. Oliver, Arrow and Crower I know make these and are going to be found in engines like Pro Stock engines. These are $400+ per rod so we probably don't have to go there.

So yeah a Oliver is a upgrade. If I was going to build a crazy HP small block like 1,100 hp, I would definately throw a set of Olivers in there and not worry. Going to a custom rod, I would go with one of the Crower Maxi Lites just because I like the weight/hp choices. Oliver rods will also find their way into my Enigne Masters motor this year.

BTW we are offering the Oliver Rods in the GP too, they are going for $1055 and up which is about $150 of the list price.

We can get into another serious rod discussion here if everyone wants too.

Bret

 

Yes please do.. we can all learn something new

 

Hey Bret....

in your howard's link i was looking at there was a notation where it said "M.S. aerospace bolt upgrade"

Are these the rod bolts that have M.S.A. stamped on them?

My rods have those and i could never find out any info on them other than what the person who sold them to me told me which basically was that they were made from an aerospace company and were cryogenitcaly treated

just curious if you know anything else about them

 

Oliver billets here

 

That is the company, but I don't know about the processes they do on them. I will look into it though.

I think the Old Engineer is working on a long post for this topic right now.

Bret

 

Why "billet" rods and not forged? A couple of thoughts:

"Billet" just means the rod is machined from a bar or slug of steel, say 4 inches wide x 1-1/8 inches thick by maybe 9 inchs long. If vacuum melted or Aircraft Quality (AQ) 4340 or 300M or whatever is used, the piece of steel has been made by a process which virtually eliminates contaminates, dirt, junk, etc. and has no voids, laps, seams, etc.

Forgings, on the other hand, are made from a bar of steel which is literally hammered into shape when red hot, with all of the scale, etc. from poundng on the metal getting on or into the surface. Also, the forging heat "decarbs" or removes carbon from the surface of the forging, since it is done in air and not a vacuum.

The good things about forgings:

"Grain flow" is often thought of as the reason a forging is strong. When steel is rolled into a bar when first produced, the grain structure in the metal is stretched in the direction of the rolling, or along the length of the bar. During the hot forging process, metal is not removed, it is reshaped, and the grains are stretched and follow the contours of the forging. This does increase strength in those areas to some extent. How much depends on the exact forging process, which is often not well controlled.

The best thing about forging is economics. The as-forged part is a "near-net shape". Very little material has to be machined off to finish the part. For a 650 gm (1 lb 7 oz) finished rod, the rough forging might weigh about 900 gm (2 lbs). Removing metal costs money. The billet for a 650 gm rod weighs about 11-1/2 lbs! That's 10 lbs of very tough metal that has to be machined away.

Most billet rods are subsequently hardened and tempered after initial machining. Tensile or yield strength is in fairly direct proportion to final hardness, so it can be controlled to a few percent in the billet rod. In an un-heat treated forging, this isn't so. If the forging is hardened after manufacture, the grains reform and become like the billet grains, but withourt the purity of the metal.

If a process called martempering is used on the billet rod, the part achieves the same hardness and strength in the thin and also thick sections, distorts very little, and is very strong as well as very tough. It will bend before it fractures catastrophically.

One way to use a forging that I like is to forge the part oversize then fully machine maybe 1/16 in. or more from all surfaces. This eliminates many of the bad things about forging, and retains the good ones. The economy of machining away maybe 1 lb rather than 10 lb saves a bundle.

Bottom line is that if I had my choice and enough $$, I'd choose an AQ 4340 billet rod which had been martempered to the appropriate strength level. Would I do that for a 500 fwhp 350-400 cube V-8? Nope, not unless the rods were free!

BTW, the above rant also applies to billet vs. forged crankshafts, but with the cranks there is even more room for forging problems.

My highly-opinionated $.02.

 

Thanks for the great info! Its always nice to learn something new and interesting.

 

This isn't a bad link, though it's about cranks http://www.scatcrankshafts.com/lawofthelongarm.pdf the principles are the same.

As far as rods go, the ranking of billet over forging is not an absolute. As the Old One said "one way to use a forging that I like is to forge the part oversize then fully machine maybe 1/16 in. or more from all surfaces. This eliminates many of the bad things about forging, and retains the good ones. The economy of machining away maybe 1 lb rather than 10 lb saves a bundle." This is sometimes referred to as a "fully machined" forging.

The process of fully machining forged rods eliminates undesirable surface imperfections and allows improvement of the shape for increased strength and/or reduced mass. The manufacturing cost reduction made possible by CNC machining has made it much less expensive to produce a fully machined forging that has a billet-like surface but still has the circular grain flow inherent in a forged rod. In a billet rod, the lack of longitudinal grain flow in the shoulder and cap can compromise the ultimate hoop strength in the big end up to an estimated 15%, according to some people.

No matter what rods you use, get the highest quality bolts. This is absolutely where you do NOT want to skrimp or just "get by".

Rich Krause

 

I dont think it warrents its own thread (rod bolts), so could we include discussion on the them also? I see everyone say use the highest quality, etc. but dont talk about specifics of rod bolts.