Crack Powdered Rods and More Q’s (Modular V8 info)

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JExpedition07

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Regarding rods and pistons specifically....Anyone know about these crack powdered metal connecting rods and why they use them? There is a good article on the 5.4L Triton engine out there that explains we have “crack powdered forged” connecting rods and genuine forged pistons from the oem. The newer Modular 5.0 Coyote platform also uses crack powdered forged connecting rods. I was watching a tear down video on the new 2020 6.7L PowerStroke Diesel and the techs said they also use Powdered Rods. I have always heard cast were cheap, and forged was the way to go. Where do our powdered connecting rods fall on the spectrum? They have to be able to be made pretty stout if they use this tech in the 6.7 Diesel.
 
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TobyU

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I assume they are a good version of PIM style even though I think PIM is mostly inferior and weak.
The "forged" could be a technicality definition for marketing.

Old style was cast- where you pour hot molten metal into a form (cast) and let it cool or
Forged where I guess the took a block of metal and cut and grinded and shaped it and beat in with hammers etc to forge it into shape.

The 'cracked' part is only about how they make the rod cap removable.
They use to cut them somehow or maybe cast the top long rod and the small bottom cap separately.
Cracked makes the whole rod at once and then they break (CRACK) the cap off like you would snap glass after scoring in with glass cutter.

The cracking makes two pieces which fit back together nicely since all highs and lows line up.

I still think we should be easily able and better off to finish both mating areas flat and maybe we can...but maybe these tiny imperfections that fit together hold it together BETTER with no lateral movement or walking etc.

I don't know exactly but I prefer overkill in pieces that are under high stress at high rpms inside of engines and hard to replace and do damage to other parts when they fail.

I likes to old strong forged rods. I don't even thing some of those were built strong enough.

I WANT BULLET PROOF!!
 

jeff kushner

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Good question JE.....the various metal strengthening processes have progressed seemingly exponentially in the past 25 years or so.

The fundamental difference between cast & forged;

Cast is pouring metal into a mold....forging is working with a solid piece of metal, cutting and shaping to the final desired shape.

Back in the day......the thinking was...Cast=cheap & Forged=Stronger

One of the reasons for that paradigm was that manufacturer's were not quite up to speed with how much silicone was added to the castings. Suzuki most notably in the motorcycle world fell victim to this in the 80's when the too-high silicone content of their pistons caused catastrophic destruction after the mileage got much over 40K. The pistons often simply disintegrated!


I am a plumber by trade.....cast iron cracks....in fact I've cut 10" Cast iron piping inside of 20 minutes with nothing but a hammer and brick chisel.

My car, an '02 factory supercharged, has forged pistons.....all of my high performance 2 stroke engines have Wossner forged pistons & IMU forged rods.

My guess is that the bean counters place the cost of crack cast rods slightly above that for cast and slightly below that for forged rods but when you are dealing in counts of 300,000 or a millions rods, it adds up quickly.

Stippling the surface of metals, indents like a golf ball, which I think this process emulates to some extent does increase sheer/compression and tension strengths b/c of the changes in surface tension it causes but it can do nothing for the inside of the metal. That's why heat treating works so well, it envelopes the entire piece.

jeff
 

TobyU

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Good question JE.....the various metal strengthening processes have progressed seemingly exponentially in the past 25 years or so.

The fundamental difference between cast & forged;

Cast is pouring metal into a mold....forging is working with a solid piece of metal, cutting and shaping to the final desired shape.

Back in the day......the thinking was...Cast=cheap & Forged=Stronger

One of the reasons for that paradigm was that manufacturer's were not quite up to speed with how much silicone was added to the castings. Suzuki most notably in the motorcycle world fell victim to this in the 80's when the too-high silicone content of their pistons caused catastrophic destruction after the mileage got much over 40K. The pistons often simply disintegrated!


I am a plumber by trade.....cast iron cracks....in fact I've cut 10" Cast iron piping inside of 20 minutes with nothing but a hammer and brick chisel.

My car, an '02 factory supercharged, has forged pistons.....all of my high performance 2 stroke engines have Wossner forged pistons & IMU forged rods.

My guess is that the bean counters place the cost of crack cast rods slightly above that for cast and slightly below that for forged rods but when you are dealing in counts of 300,000 or a millions rods, it adds up quickly.

Stippling the surface of metals, indents like a golf ball, which I think this process emulates to some extent does increase sheer/compression and tension strengths b/c of the changes in surface tension it causes but it can do nothing for the inside of the metal. That's why heat treating works so well, it envelopes the entire piece.

jeff
I don't really know if the metal strengthening processes have progressed exponentially in the past 25 years... But things have certainly changed some. They were already pretty smart 30 years ago knowing how to make strong connecting rods and such. Most of the changes have either been done to save money, or to increase the speed of production or the ease of production.
I think usually what happens is the thought process is they need to change something to make it cheaper or easier or at least someone wants them to and they start doing that but they end up with and figure products or problems so then they have to try to use technology and work to get back to the quality or durability they had in the first place. There are some things we have improved quality on but most things today are not as good as they used to be.
It is also sad that sometimes instead of improving the quality to where it used to be or needs to be to hold up they will just redesign lots of things or items around that component to makeup for it's inferior qualities in that particular application.

And the high performance auto world I don't remember there being a problem with high-quality connecting rods as long as you were willing to spend the money.
Also, I look back at what we used to get some of the high quality performance parts for price wise and really wish we could get things for those prices today! We have been spoiled for the past 25 + years with stuff being mass-produced and copied and prices dropping down to super cheap. Yes, the quality suffered at least some but most of the cheap things we buy especially in electronics are at least adequate if not better than that.
Today, even when you're willing to spend good money or Top Dollar on performance parts, metal, Etc... You still have a fear or concern that you might be getting inferior quality because sometimes even companies with the best of intentions don't have any control of the raw product they have to buy.
 

jeff kushner

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Agreed Toby that often parts are made smaller/lighter/cheaper at the expense of long term reliability.

In the motorcycle world, makers will often revise a model by trimming weight EVERYWHERE! Honda even went to the extreme of going to thinner lens on the speedometer and odometers!

Frames cracking at headjoints b/c of weight savings. Kaw and Suz got into real trouble with cracked frames on 175HP bikes!

No where do we consumers see this more than in the Appliance world.....cheap parts cause the breakdown of expensive machines.


jeff
 

TobyU

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Yes, they've been cheap eating the quality of parts to keep the price low or to lower the price for decades. But I don't remember having any problem in the old days with Crower rods or Carrillo or the other brand-name forged Rod makers. You also had high quality aluminum rods for certain applications to.
 
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JExpedition07

JExpedition07

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Toby is pretty backwards in a lot of his opinions. Fact is metallurgy has gotten a lot better in the last 25 years and engines last longer. The Modular V8 is built a lot stronger than the Windsor series pushrod V8 engine it replaced, that is evident just by looking at the main caps/bolts and the block itself.
 

TobyU

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Toby is pretty backwards in a lot of his opinions. Fact is metallurgy has gotten a lot better in the last 25 years and engines last longer. The Modular V8 is built a lot stronger than the Windsor series pushrod V8 engine it replaced, that is evident just by looking at the main caps/bolts and the block itself.
Not really. We can all nitpick certain things that show either positive or negative. The modular engines were great engines. They had them perfected by right around 96 to 97. These go 300-plus Thousand Miles without ever having a valve cover off. They are great. Now with the three valves they are not so great anymore. They have to have timing chains and cam phasers replaced often head under a hundred twenty five thousand. I understand I think it's you who have had three or four of them with no problems but as you start researching there are a lot of people with problems. Sure the percentages are still pretty low but with the millions of these on the roads a lot of people have problems with the timing components and cam phasers. This simply did not happen on the two valve motor. Same basic design but things have changed some. This is actually not a metallurgical problem. They didn't cheap and anything to cause the problem. This was about because for fuel mileage and infinitely or constantly variable valve timing Etc. The Honda VTEC was one of the first engines commonly in America to have variable valve timing but it was a much more simplistic design with only two positions. It really gave any problems.
Let's talk about firearm manufacturer parts being made out of PIM metal, then tell me that metallurgy is better than it was 20 years ago.
But as I said, this is just another example of us being able to nitpick certain things that are better or certain things that are worse.
Overall, the longevity and durability of engines in cars improved a lot from from the cars in the 60s through late 80s.
The ones built from the late 80s on we're much better then these older decades. Now, for many of them the trend is going the other way.
It's not quite an epidemic yet but it's getting to epidemic proportions.
Forged steel connecting rods are not better today than they were 25 years ago! In fact, it's hard to get as good of quality iron or steel as it was 25 or 30 years ago. Most of the stuff is recycled and not as good as the old original stuff we had.
Expensive, high-performance block manufacturers are forced to buy steal from Chinese foundry's because there's no suppliers in the US supplying it from what I read just a few months ago.
They don't care about costs as the people buying their blocks will pay an extra few hundred to couple of thousand for the quality without asking any questions.
I read two or three different manufacturers who said they would have gladly paid more for us sourced Steel but there was none available. They often have problems with the quality of the import steel or forgings.
Technology does often improve things but sometimes when people are insistent on applying technology to tried-and-true things that already worked just fine, they introduce problems that then have to be overcome. Often you only get back to where you started from and sometimes you don't, and sometimes you end up a little better off. But almost always the end result is a little bit cheaper for them and that's what they're going for.
The only thing that's improved and they high performance race car world and aftermarket parts has been tolerances and replicating these tolerance is so part uniformity and consistency.
They have also improved valve sealing because of very minut an exact machinery. In the old days a 3 angle valve job was top-notch until like around 2000.
Now people consider that a joke. They have like 6 Plus sealing angles or whatever and if you were to do a 3 angle valve job on a newer set of heads you would be diminishing the performance and the sealing ability.
This has nothing to do with Metallurgy though or the quality of the valves or aluminum heads being machined.
 
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