Manley 6.125 Pro I Billet rods GOOD rods? what other rods close or little better
03-18-2008, 10:02 PM
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Manley 6.125 Pro I Billet rods GOOD rods? what other rods close or little better Looking to buy a set of rods Thinking Manley 6.125 Pro I Billet rods. How are they? Are there other rods that are close to these or little better?
03-19-2008, 12:53 AM
#3
I know this isn't the answer you're looking for, I'm going to go ahead and throw a wrench in the works anyways. I have NEVER seen an aftermarket rod break, regardless of the manufacturer and been able to point my finger and say "root cause of failure". Every time an aftermarket rod has been broken its been IMO because of rod bolt failure or detonation. The only difference you get between ANY h-beam rod is who manufactures the bolts for it and where the rod was finished. More often than not they're all ARPs anyways.... Hmm.....
As far as billet rods go yeah, you'll find some that may be a few grams lighter on the small end but they'll all be near the same. If you had Manley pro billets and lunati pro billets with the same rod bolts I would venture to say the rods are damn near identical. You'll encounter some small differences but I am willing to bet both are about equally tolerant of detonation and both would be good to the same RPM if the same pistons are used.
So why are Carillo billet rods better than say Manley's or Lunati's? Well, they don't use ARP2000/L19 hardware, they use SPS Carr bolts which have a much higher tensile strength, however they are much more brittle and you better not ever get skin oil on them.
Morale of the story. Rod bolts will always be the weak point of the rod itself assuming there's no defects in the rods. RPM is the only limiting factor at that point.
As far as billet rods go yeah, you'll find some that may be a few grams lighter on the small end but they'll all be near the same. If you had Manley pro billets and lunati pro billets with the same rod bolts I would venture to say the rods are damn near identical. You'll encounter some small differences but I am willing to bet both are about equally tolerant of detonation and both would be good to the same RPM if the same pistons are used.
So why are Carillo billet rods better than say Manley's or Lunati's? Well, they don't use ARP2000/L19 hardware, they use SPS Carr bolts which have a much higher tensile strength, however they are much more brittle and you better not ever get skin oil on them.
Morale of the story. Rod bolts will always be the weak point of the rod itself assuming there's no defects in the rods. RPM is the only limiting factor at that point.
03-19-2008, 08:14 AM
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There are many factors involved regarding the strength of a rod. The biggest being the material it's made from, and the fasteners used. To say that all H-beam rods are basicly the same is not accurate. There is a reason the imported rods cost much less, and that is because of the material. We have seen rods break, and when they do it's usually right below the wrist pin. That is the weakest part on any rod with a tapered beam, excluding the bolts. All rods have a cycle life. In alot of instances, you may never reach that point of cycle life, especially in a moderate power level. The Manley Pro Series rods are a good piece, and for your intended use they are adequate. There are better pieces available, but it depends on your budget, and how much additional 'insurance' you're willing to pay for.
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03-19-2008, 10:54 AM
#8
There are many factors involved regarding the strength of a rod. The biggest being the material it's made from, and the fasteners used. To say that all H-beam rods are basicly the same is not accurate. There is a reason the imported rods cost much less, and that is because of the material.
So what rod of yours broke just below the wrist pin? I also highly doubt it was from sheer power alone, I would tend to think if it were going to break from power it would be closer to the big end right before the radius that starts the big end. It must have had detonation involved with it, a pretty serious stress riser or you ran wrist pin tolerances too close and the pin "siezed up" at an inopportune time. Now that I think about it there's only one person I know of that's broken rods from sheer power. Gale Banks, 20 years ago when he was doing turbocharging in Top Fuel he would split rods down the length.
03-19-2008, 03:29 PM
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I have only visited one forging plant, it is here in Michigan. They forge a few different blanks from two primary materials, 4340 and 300M. The quality of the material is of great concern in high load engines. Sometimes the better quality material is used so the mass of the rod can be lowered without failure. Most of the rods I have seen fail in my life had spun bearings, but overloaded broken rods seem to go below the pin everytime.
Kurt
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03-19-2008, 03:51 PM
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From what I have seen of the Manley rods is they are underrated, or can handle a significant amount of power more then what Manley claims.
03-19-2008, 04:05 PM
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I totally agree with kurt,the most important diff is the material,the upper end forging has a more pure material than the chinese forgings.The typical h beam will handle up to 1000+hp with no problem,after that i always use the lunati,have them in my own engine,it sees 9000rpms all the time,even with those junky arp2000 bolts
03-19-2008, 04:12 PM
#12
If you knew a little about this guy I doubt you would be calling BS. FYI, the company he works for builds the new NASCAR LSx spec motors. Sponsor or not, high or low post count, i'd take his advice on just about anything engine related. We should all be greatful to have people around here like him, Katech, W2W, etc. sharing info with us.
I'm sorry, I have to call BS on this. K1,Compstar,Eagle,Manley H, Scat and Lunati H are all made from the same rod blanks, there's only a handful of forges in the world that will make rods and major one is in China. The difference in price isn't the material difference its who got first pick of the batch, where the rod was finished from the blank and what hardware it comes with.
03-19-2008, 06:47 PM
#13
I have only visited one forging plant, it is here in Michigan. They forge a few different blanks from two primary materials, 4340 and 300M. The quality of the material is of great concern in high load engines. Sometimes the better quality material is used so the mass of the rod can be lowered without failure. Most of the rods I have seen fail in my life had spun bearings, but overloaded broken rods seem to go below the pin everytime.
Kurt
Kurt
03-19-2008, 06:57 PM
#14
Like the others have said, Most of the H-Beam rods will handle what you're looking to get out of it (1000hp). I wouldn't be too picky on brand. I went with the Eagle H-Beams. TSP has a twin-turbo shop car making 1200 wheel hp on a mustang dyno with the Eagles.
03-19-2008, 07:12 PM
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I totally agree with kurt,the most important diff is the material,the upper end forging has a more pure material than the chinese forgings.The typical h beam will handle up to 1000+hp with no problem,after that i always use the lunati,have them in my own engine,it sees 9000rpms all the time,even with those junky arp2000 bolts
Does anyone have micrographs (cross sections) and or SEM type data that indicates a distinct cleanliness issue (porosity,inclusions,or segragation) in relationship to the Chinese H beams vs other manufactures with like type Rods of a given tensile strength (maximum HP rating)?
03-19-2008, 09:59 PM
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It is Trenton forging in Trenton Michigan. They supply Dyers with 300m and Howards with 4340, and they might supply others. The process they use is multiple strikes on each part, very interesting (LOUD!) to watch and a proven way to produce a solid part.
Kurt
Kurt
03-20-2008, 12:04 AM
#17
Cool, thanks. Its always nice knowing baller race parts are made in America.
03-20-2008, 03:37 AM
#18
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I totally agree with kurt,the most important diff is the material,the upper end forging has a more pure material than the chinese forgings.The typical h beam will handle up to 1000+hp with no problem,after that i always use the lunati,have them in my own engine,it sees 9000rpms all the time,even with those junky arp2000 bolts
Hydrolock an engine and you will see all sorts of rods do different things! I saw a whole lot after Katrina and a few every once in while from NOS deals with head gaskets gone South. Trying to compress water will do quite a number on any rod and you will find the weak spots!
