I have seen the famous connecting rod picture that is floating around but had never seen any of the rods in person. The ford rod shown in the picture is not a 6.0 diesel rod. A local diesel repair shop has the rods their to see and the 6.0 ford rod looked very beefy and is actually larger than the Cummins rod in some critical areas. Also, the Cummins rod is crude with a rough finish and looks like 1950's or 1960's technology. Comparing the 6.0 and the 7.3 rod, the 6.0 rod looks much stronger. The Ford rod in that picture is from a Windsor or a straight six I think. The owner of the shop runs a twin turbo 6.0 diesel and says the engines bottom end has been 100% reliable. Having the bedplate instead of the seperate main bearing caps adds alot of strength.

Just something I learned and thought some of you would be interested.

Joe

 

I agree with you.. one thing though i thought i would tell you that its Cummins there is no G in there... :-) But yeah I have heard that the rods were looking strong on our 6.0's. I personally havent seen any but I dont really get a chance every day to look into a broken down engine...

ryan

 

That one right there is a 6.0 rod. You can tell by the enormous wristpin and semi-H-beam shape.

They look beefy, and for stock purposes they aren't bad. However, under high boost and timing load they will eventually break. Being powdered metal, the yeild strength just isn't there to handle prolonged high performance stress. Problem here isn't the design, it is the material they are composed of.

The only company I know of hitting extreme boost levels is Hypermax, and they have soild billet 4340 rods in the bottom. I will most certainly agree with you that the crank and bedplate setup is extremely durable; the bedplate is huge and is anchored down well, and the crank is equally as big and is forged from the factory.

 

That looks like one bad rod ! Ouch! I can tell you from my own experience that even Carrillo rods break. But my point is that PM technology has come a long way and I think is now in many ways superior to a forging. The new Corvette engine and Porsche engines are now PM rods as is Ford F-1 engine.

This is from an article I found on the net. It's good reading with some interesting figures on the end

"What about the mechanical properties of the forged PM rod versus the forged steel rod? “The mechanicals are equal to or better. They are in fact what you want them to be. Name it and we can match nearly any requirements. Powder metal parts always have to overcome this myth of inferiority, but it just isn’t there,” Letourneau explains.

“In this application the ultimate tensile strength is basically identical and the yield strength superior by some margin. Through the addition of manganese sulfide to the powder, we have a material that is machinable and still has a hardness in the Rockwell (C) 26-27 range. The microstructure is isotropic and lends itself to excellent machinability.
“But because this is a near net shape technology, there isn’t that much machining anyway, the capital cost for machining equipment is less, and the dimensional control is much improved. We’ve completely eliminated weight pads on both ends of the rods and thus the subsequent machining and processing required to meet weight specifications.” The connecting rod for the 7.3L engine is quite different from that for the 6.0L diesel.

The 7.3 rod has a straight split on the big end while the 6.0L rod features an angle split. On the small end, the 6.0L rod features teepee geometry to provide a larger bearings surface to absorb the high pressures on the underside of the piston pin. The material is a cuprous iron alloy with high carbon and a manganese with that program. sulfide additive. Copper content is approximately 3 percent. Particularly interesting, on the large end of the straight split rod the lower end cap fastens to the main part of the rod with through holes that can be drilled conventionally. But with the angle split rods on the 6.0L, the lower bearing cap mates to the main part of the con rod with cap screws secured in blind threaded holes.

Elimination of weight pad stock from both the large and small end of the connecting rod is terribly large advantage. Typically, you need to through a process of weighing the pin end mass and the crank end mass and then balance machining each end. Hardly an exact science, conn rods could instead be classified into several weight categories and then matched up assembly into a specific engine. Dealers and distributors may need various weight classes in inventory for aftermarket needs.

All this tedium is eliminated with forged PM connecting rods because the weight tolerance is so close. The 6.0L connecting rod has a target weight of 1,450 g. In forged steel, the weight variation of the pin mass would be +/- 20 g versus +/- 4 g for the forged PM rod. On the crank end, forged steel would have a variation or +/- 70 g. versus +/- 5 g for the forged PM.

Forged PM parts are growing in application they can often combine the mechanical properties of steel forgings. Basically, you start with a raw powder metal blend with a machining enhancer MnS); then compact it to near net shape in the green state; sinter it in a rotary hearth furnace in a nitrogen enriched neutral environment; forge it in a single stroke to full density; and then finish machine. No subsequent heat treating or stress relieving is required. The 6.0L PowerStroke is truly an interesting application, but PM rods in the overall have grown by leaps and bounds since the mid 1980s. Metaldyne has produced some 230 million of them since 1986 (more than half of that in the past five years) and claims to have market penetration just over 40 percent. OEM automakers have typically retained in house machining of critical engine components such as blocks, heads, crankshafts, camshafts and connecting rods and pistons."


<TABLE cellSpacing=0 cellPadding=5 border=1><TBODY><TR><TD bgColor=blue colSpan=4>Mechanical Properties</TD></TR><TR><TD bgColor=blue colSpan=2></TD><TD bgColor=blue>Forged Steel</TD><TD bgColor=blue>Powder Forged</TD></TR><TR><TD>Yield Strength </TD><TD>Rp0.2 </TD><TD>550 N/mm2</TD><TD>670 N/mm2</TD></TR><TR><TD>Tensile Strength </TD><TD>Rm </TD><TD>1050 N/mm2</TD><TD>1030 N/mm2</TD></TR><TR><TD>Elongation </TD><TD>A5</TD><TD>10% </TD><TD>11%</TD></TR><TR><TD>Density </TD><TD>p</TD><TD>7.82 g/cm3 min.</TD><TD>7.80 g/cm3 min.</TD></TR><TR><TD>Modulus of Elasticity </TD><TD>E</TD><TD>206 GPa </TD><TD>207 GPa </TD></TR><TR><TD>Poisson’s Ratio</TD><TD></TD><TD>0.294 </TD><TD>0.294</TD></TR><TR><TD>Core Hardness </TD><TD></TD><TD>28-34 Rc</TD><TD>21-31 Rc</TD></TR></TBODY></TABLE>

 

Boy is this a mouth full. don't understand all of it but it does read good

 

Actually good rod... bad kid.....big foot too...hehe...could not pass this one up~!~