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

[rjdelp7]

The Coyote, Powerstroke and EB are producing way more power than the old engines. The rods are stout and not an issue. The Coyote and Voodoo engines have had ring issues. The long timing chains and guides, scare the hell out of me.

 

[theoldwizard1]

Crack/fractured sintered (just means compressed and heated but not to melting) rids have been around for quite some time and have proved themselves to be very durable. The big win is low cost. I am sure the forged or billet steel (typically H-beam) would be lighter, but much more expensive. Making the rod as one piece and then cracking the big end off means that there is perfect alignment of the cap to the top half of the rod (no machining is done on the mating surfaces so the the small irregularity between the two piece make for perfect alignment when re-assembled). This is also a big win because cast rods will actually experience a small amount of "wiggle" at the joint under extreme loads.


TobyU, I have a "problem" accepting a few things you presented as "facts".

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.

Are we talking blocks or rods ? Not sure about cast iron blocks, but the NASCAR boys have near "infinite money" and I am sure they can throw enough money at "the problem" to get the quality they want, whether it is cast in the US or overseas.

As for forgings or extrusions of smaller steel items, there ARE small batch furnaces in the US that have extremely high quality control to make "specialty" steels. As long as the steel has the correct amount of elements (iron, carbon, manganese, etc, etc) which can only be determined will the steel is still molten, who cares where those elements came from.

If you look around the Internet there is a story about NASCAR valve strings. About 20(?) years ago, NASCAR engines would routinely break springs as the RPM started to exceed 9,000. Engine builders were buying thousand of spring and having a person sort them for height and compression, but that was still not good enough. A couple of smart engineers realized that the metal "wire" used to wind the spring was the real culprit and that they could solve the problem. It took them a few tries, but they came up with an alloy and a reliable manufacturer to make the wire to their spec. They bought the machinery to wind the springs. The result is, everyone in NASCAR buys valve springs from this one source and you almost never hear of a valve spring failure anymore (and NASCAR has changed some rules that have kept the WOT RPM from creeping up further).

 

[TobyU]

We started out talking about rods but then we were talking about different engines durability, problems, and got into different types of Metal Manufacturing and forging versus cast.
That's when I brought up the fact that I have read several times that high quality block manufacturers we're having to use overseas, mainly Chinese, steel for their blocks.
I mentioned that money wasn't an issue for them because they can easily pay the premium because their customers will also.
They were just complaining that there weren't any US ones or U S Steel steel available. I don't know how widespread this is or how accurate it was.

I did mention earlier about the cool fact that when you crack the rods it makes them line backup perfectly from all the little minor imperfections and high and low spots when they crack. That is just a cool naturally occurring thing in nature that gives you a benefit of a better connection with less movement.
I'm not sure about reconditioning these if they spin a bearing. I think they do it now but it one time they might have said you couldn't do it. A lot of things in engines are that way.
I can think of at least another one right off the top of my head that when they were fairly new, the Machine Shop said you couldn't do this or couldn't do that because of some design or some way they were made. Then, a few years later they figured out how to do it and it became standard practice.
As far as costs, I guess is slightly cheaper to just have a machine that snaps off the ride but she would think it wouldn't be that much more expensive to have a machine that cuts the ride in half so you can still make them as one piece. You would just design the casting so it makes the whole a little bigger or oblong so once you cut it in the middle and put it back together it's perfect.
I guess this might require some final Machining. I'm wondering if when they make these cracked rods if they are absolutely done once they crack them. Do they not put them back together and mic the inside or run a hone in them to make them closer to perfect?
Maybe they're close enough. I don't know. There is a slight amount of Tolerance allowed on rod bearing gaps.

 

[theoldwizard1]

I'm not sure about reconditioning these if they spin a bearing. I think they do it now but it one time they might have said you couldn't do it.

Probably not worth the cost. PM does not machine well, but it does hold tolerance and give a "good" finish when sintered.

I'm wondering if when they make these cracked rods if they are absolutely done once they crack them. Do they not put them back together and mic the inside or run a hone in them to make them closer to perfect?

I am pretty certain there is no further inspection done after the cap is cracked off.

 

[TobyU]

Probably not worth the cost. PM does not machine well, but it does hold tolerance and give a "good" finish when sintered.

I am pretty certain there is no further inspection done after the cap is cracked off.

I believe it is common for machine shops to recondition the modular rods if a bearing is spun.

I can't say for sure but I though I remembered it being listed when I checked on a 4.6 rebuild back in 2002.

 

[Greg Coleman]

I believe it is common for machine shops to recondition the modular rods if a bearing is spun.

I can't say for sure but I though I remembered it being listed when I checked on a 4.6 rebuild back in 2002.

There are bearing shells offered for some engines so you can bore the rod big end as a "reconditioned rod". Don't do it. Modern conn rods are dirt cheap.

Aside from the cost advantages, the parting line has 2 or 3X the surface area at the parting line compared to a machined interface. High-end conn rods have tight-fitting dowels between the cap and shank to prevent cap walk, or fretting between the 2 parts under high load / speed. Cracked rods have more resistance to cap walk because of the much greater surface area. Down side is you can't actually recondition them. Boring to an oversize bearing is NOT an acceptable way to go IMO.

The manufacturing process for fractured rods is pretty much done when the cap is snapped off. All the machining of the Big End, drilling and tapping for bolts, etc. is done first.

 

[TobyU]

There are bearing shells offered for some engines so you can bore the rod big end as a "reconditioned rod". Don't do it. Modern conn rods are dirt cheap.

Aside from the cost advantages, the parting line has 2 or 3X the surface area at the parting line compared to a machined interface. High-end conn rods have tight-fitting dowels between the cap and shank to prevent cap walk, or fretting between the 2 parts under high load / speed. Cracked rods have more resistance to cap walk because of the much greater surface area. Down side is you can't actually recondition them. Boring to an oversize bearing is NOT an acceptable way to go IMO.

The manufacturing process for fractured rods is pretty much done when the cap is snapped off. All the machining of the Big End, drilling and tapping for bolts, etc. is done first.

That's what I was thinking that if they spin you just replace them because since they're cracked they're not machined and you're not supposed to machine them after the fact. On the Old Rods it was common to cut the rod cap mating surfaces and then bore the big end back to round.
I just wasn't sure if I have seen it listed before on rebuild papers for modular Ford's.
I have a local machine shop nearby that does the mechanical work too. They will pull your engine out and fully rebuild it and put it back in for a very fair price. They have been in business for probably 40 plus years and they don't do anything halfway. They pride themselves on very quality work.
Most of the work is people buying complete engines from them or taking their engine in and having stuff done to it but they started offering the actual removal and reinstall about 20 years ago.
I would defer to them because I definitely know their stuff.

Back in 2001 I thought I was going to need a 4.6 L replaced in a town car I bought across the country.Even with my commercial discount at the local part stores the price of the long block was going to be so much that these people would have pulled the engine fully rebuilt it and gave me a 15 month 15000 mile warranty for $400 more. It wasn't worth getting the engine hoist out for $400. Luckily it was just a minor problem and I didn't have to pull the engine or even pull the heads once I got the car home.