Zappster, or anyone heavy into cars, question

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What are OE connecting rods usually made of? Cast iron or forged steel? I want to do something wierd with 2 connecting rods. Without getting into too many details, the 2 connecting rods will wind up being welded together. For what I want to do, I have found that the Cadillac 472/500 rod has the perfect size big end.I got a line on some rebuilt OE rods, but not sure what they are made of. I don't want to have to spring for Chromoly rods if I don't need to. If they are Cast Iron...I never welded cast before. I do however have some NiRod that is about 30 years old...
Reply:Cast, unless you buy expensive aftermarket rods, then they are forged.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Nah, many OE's used forged rods in different motors.  Anything that had a little pep to it, or used for heavy duty work is likely to have forged internals.  I'm not sure about Caddy's.  They weren't intended for very Hi Perf use, so they are probably cast.  You should check out some Caddy sites and check out the engine specs section.  You might find some info.  I've learn from here that it's probably better to silver solder them if they are cast with a high nickle content rod.  Some one correct me if I'm mis-informed.
Reply:Originally Posted by MicroZoneCast, unless you buy expensive aftermarket rods, then they are forged.
Reply:They could be either cast steel or forged steel. OEM's have used both. I don't remember which method Caddy used. Here's a rule of thumb. Wide parting beam, approx 1/8" to 1/4", for forged parts. Narrow parting beam, about 1/16" for cast parts. There are also powered metal rods but not in that old Caddy.
Reply:And another thing..Welding rods (connecting) are a waste of time..It will never last.. It will never weigh the same as the others no matter how much you loose metal off everything else.. Totaly out of balance and boom is the end result.. You cant imagine how much bullcrap that HAZ will not put up with..Especially if you attempt this with cast rods..let alone forged..I would not sign them.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:The OEM's did use forged parts but they are only MAYBE 10% of total production. He would have better luck playing the lottery than finding forged internals in a used motor. Anything used the roundy-round guys usually take out and use for themselves, then blow it up, put together another motor and do it all over again. The same holds true for trying to find a positive locking rear axle in the junk yard - good luck. Forging parts costs money, OEM's use it as little as possible in their motors. I know for a fact, GM doesn't use it as often as they should. Most of their motors use Hypereutectic pistons. Hell, even the new LS7 with 505hp uses Hyper pistons with titanium rods. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:(Not you John)Forging parts costs money, OEM's use it as little as possible in their motors. I know for a fact, GM doesn't use it as often as they should. Most of their motors use Hypereutectic pistons. Hell, even the new LS7 with 505hp uses Hyper pistons with titanium rods.
Reply:There are tons of OEM forged rods out there but not all forged rods are the same. Many production motors have forged mild steel rods. OEM forged chrome moly are in deed rare. Some OEMs such as Buick V8's used only cast rods. Others always had forged mild steel rods. Some could have either. Now that I said that some one is sure to have a photo of an OEM forged Buick rod.
Reply:I don't intend on using them in a motor...nothing they were designed for, so balance is not an issue.
Reply:Zap - a set of LS7 Titanium rods can be bought for $1500 to $2,000 depending on if you're a distributor or not. A set of Lunati LS1 Pro connecting rods are $700 - 1200...I don't think that's a 1:8 ratio  tresi - tons? How about some specific production information? OEM chromemoly rods?John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by eastcoasteddieI don't intend on using them in a motor...nothing they were designed for, so balance is not an issue.
Reply:Originally Posted by tresiI've seen many people make old rods into to tail plpe hanger and other things. They usually weld ok for that kind of thing.
Reply:Originally Posted by tresiI've seen many people make old rods into to tail plpe hanger and other things. They usually weld ok for that kind of thing.
Reply:Clean them, Mig them up both should do ok.
Reply:Hey e/c eddie,You post indicates you want to connect these 2 rods for other than what they are intended. Your best result for a solid bond will be silver solder as bigcountry1009 suggested. Silver solder for any steel or iron casting will work excellent and because of its' low melting point, will not do extensive damage to the casting. Sil/sol is generally 60(brass)/40(silver) content and is strong. An example is the fact all cemented tungsten lathe & milling cutting tools have the tungsten attached to the steel tool with sil/sol, as sil/sol is the only metal that will attach to and bond tungsten. Ever see a high speed lathe with a 2" tungsten carbide tool rip off 1" of steel in a single pass? Sil/sol has many uses and should be in every welders tool arsenal....DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:I planned on butt-welding the I-beams together , so that the big-ends of the rods would be directly opposite each other in a horizontal line. I can't solder a butt joint. I did think about soldering, though. I have soldered steel before.
Reply:Why can't you solder a butt joint??  Just bevel the I-beams a bit and lay a bead in the groove.  If it's clean, it should flow pretty well.  You might want to preheat the rods a bit too to burn off any oil or anything.
Reply:Only Cadillac and Pontiac used cast rods in their OEM motors, everybody else used forged steel.  I'm not sure of the alloy, OE forged crankshafts from GM were 1053.
Reply:Look at the parting line on the side of the beam. If it is a thin line it is cast, a wider part line (1/4 to 3/8") with grind indications indicates a forged rod (or any other part for that matter). In the forging process the dies do not come completely together and material is forced out between tham at the parting line making the wider line and requiring grinding.JimCut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:Originally Posted by 76GMC1500Only Cadillac and Pontiac used cast rods in their OEM motors, everybody else used forged steel.  I'm not sure of the alloy, OE forged crankshafts from GM were 1053.
Reply:editedLast edited by tresi; 04-16-2007 at 07:44 AM.
Reply:Like I said cast steel. Many people see that they are cast and assume it's cast iron. Just like steering arms and knuckles if it needs to bend before breaking it's most likely cast steel. There's a few old Potiacs from the mid 60's with forged rods. They were hard to find 20 years ago so your not likely to find any more.
Reply:Originally Posted by tresiLike I said cast steel. Many people see that they are cast and assume it's cast iron. Just like steering arms and knuckles if it needs to bend before breaking it's most likely cast steel. There's a few old Potiacs from the mid 60's with forged rods. They were hard to find 20 years ago so your not likely to find any more.
Reply:Originally Posted by tresiLike I said cast steel. Many people see that they are cast and assume it's cast iron. Just like steering arms and knuckles if it needs to bend before breaking it's most likely cast steel. There's a few old Potiacs from the mid 60's with forged rods. They were hard to find 20 years ago so your not likely to find any more.Forged rings like a bell when struck. Cast clunks.
Reply:Originally Posted by 76GMC1500You're exactly backwards.  There were a few Cadillacs and Pontiacs in the 60's with cast rods, everything else is forged, except GM's new powder metal rods starting in the mid-90's.  I don't know what you would call those.
Reply:Amen to the above statement. Cast steel or Forged steel, for what it seems you are trying to accomplish it would not matter. Clean them with some heat to drive out the dirt gremlins and then weld them like steel.
Reply:Originally Posted by eastcoasteddieI don't intend on using them in a motor...nothing they were designed for, so balance is not an issue.