tempering the connecting rods

[AKheathen]

ok, so i'm about to send out some connecting rods to put on one of my cranks, and i'm thinking about tempering them frst. i don't know if it would be a good thing to do to a connecting rod or not, but it sounds like a good idea to me and free, too.

[bonerific250]

Sounds like a good idea, but I would make sure the person doing it knows what their doing, Tempering does a couple of things it hardens, strengthens, but at the same time it makes the steel softer. Heating the steel and holding it below its AC-3 line ( the temp. @ which steel hardens) for certain amount of time around 212 degrees for 1 hour per inch of thickness then let air cool. I would do it bulletproof rods.

[blowit]

ok, so i'm about to send out some connecting rods to put on one of my cranks, and i'm thinking about tempering them frst. i don't know if it would be a good thing to do to a connecting rod or not, but it sounds like a good idea to me and free, too.

 

 

 

What are you trying to achieve? Do you know the alloy of the rods you are working with? Most all structural components such as rods will be tempered from an OEM for obvious reasons. Most all our our components get tempering free of charge to us because it is like having the potatoes without the gravy.

 

I think I would for go the temper and just use them. Without specific knowledge of the part and alloying, you run the risk of distortion of the precision ground concentricity of the rod centers. Grinding is the last step.

 

 

 

Mull Engineering

[J-Madd]

Is the connecting rod the weakest link in the rotating assembly? Don't know, just asking.

[blowit]

Is the connecting rod the weakest link in the rotating assembly? Don't know, just asking.

 

 

 

Depends entirely on what you are doing to it. Steel con rods tend to hold up extremely well. Hydrolocking never seems to turn out too well though...

 

 

 

 

B

[Jereme6655]

Depends entirely on what you are doing to it. Steel con rods tend to hold up extremely well. Hydrolocking never seems to turn out too well though...

 

 

 

 

B

 

 

haha....good point....9000 revs and water dont usually turn out good...tempered or not. even if the tempering were to hold up to a hydro-lock it would just the force into another part that can't hold the force haha

[AKheathen]

yah, it really depends on what force is being applied as to what the wekest link is..........my general opinion is that the ball bearings hands down, then the tiny needle rollers, then the rods, but something as simple as an improperly seated crank, or compression imballance will leave all that unharmed and rip the crank apart easy........so, the thing is, that they are good spec stock rods, and i already got one a little hot. enough to color the copper coating, and i figured it's a simple 10.9 japaneese steel, or they would not bend as much as i've seen and simply break. the plan is to relax it over 1200, then a few heat/quench cycles to haredn it back up and re-hone, but i'm also thinking about case hardening, depending on how much the gallon costs.....i have my metalurgy mentor here in town with me so, we'll get it. thanx for the input guys

[blowit]

I would caution you on trying a carbon rich "paste" product for way of case hardening for a structural application. There just is not enough control of case depth to be accurate. I will admit that getting too much depth would not be a concern with that product but the heat being applied is rarely controlled to any exact science (torch or induction) and that can really cause structural problems. Usually a con rod is made from a carbon poor material so hardening on it's own is more difficult so a carbon rich material must be introduced.

[AKheathen]

i was out lookin for the powder, just now, actually.......just missed the welding shops, so i got stuck googling in other stores, lol

[jbooker82]

I think I would rather have a con rod bend than break. There are plenty of guys running a stock welded crank with a cub cylinder with no issues.