What is a Fractured Connecting Rod? Cracked Rod? Advantages and Disadvantages.

[@XzX-7]

I'm not a mechanic and today is the first time I've ever heard of this process. Thanks for answering some questions.

[@Nobody-ld7mk]

Pro's, Zero Cap-Walk under severe loads. Cons, Require oversize O.D. bearing shells when resized/refurbished.

[@nickd.7267]

If I'm not mistaken the first modular engines from Ford used this, which began production in 1989

[@hopingforthebest1.9]

Honestly didn't know that was a thing, neat!

[@skinlab4239]

Why? The internet is vast.

[@volvo09]

Yeah holy shit! I don't build engines, so i didn't know. Seems like a good idea.

[@yeahok115sure]

All high revving 4 stroke sport bikes since 2004 have fractured rod and caps. The first time I found out about this style connecting rod was a Yamaha R1 I rebuilt with a dropped valve.. well I thought the rod cracked and that was a problem 😂 I even called Yamaha tech and was embarrassed when the tech told me it’s factory and I need to read my tech Manuel better.. 😂 he also said it 30% stronger at high rpm’s like 10k-14,500 rpm. It help keep the rod bolts from stretching at those rpms. It keeps the cap from walking side to side. That’s what they said not saying it’s true

[@matthewstorm5188]

“ It keeps the cap from walking side to side.” That’s the job of the dowels. NOT the bolts. Even on a machined rod, the bolts carry no shear load. As for cracked rods, if they are SO superior, then why are ALL aftermarket performance rods machined?

[@yeahok115sure]

@@matthewstorm5188 if you read my post, I never said the rod bolt keep the cap walking side to side. The fractured pattern helps with the walking. I’ve never seen a fractured rod with dowel pins. So I don’t what your talking about, a machined rod needs dowels pins because the surface is machine. As far as you question about the aftermarket world I don’t know why nor do I give a F@ck. Probably cost. Most after market rods for the moto industry are junk. I’ve seen stock fracture rods on a turbo r1 handle 600hp. The rod bolts where not stock nor where the head studs and cam. The engine for the most part was stock. The watercraft world is seeing 1200 hp with bottom ends with big ass turbo’s. It’s no secret japans know reliability and performance. So my question to you is why would the Japanese engineers use fractured rods in the highest performance highest rev’ing engines know to man if they are so inferior to standard rods

[@mrb692]

Aftermarket doesn’t necessarily mean “best”, it just means parts made by a third party to factory dimensions. Why would aftermarket manufacturers invest in a whole new tooling line and setup when their current product is meeting their demands? Ask yourself, how much does it cost to change over to making fracture split rods? How much do you save on each rod? How many rods do you need to make to break even? How many aftermarket rods get sold? How many OEM rods get sold? There’s just a tiny difference in scale there. Every second and cent of machine time they can save per rod adds up massively over the number of engines they make.

[@jacobhendrickson8935]

Yamaha was first to do this in 2004 R1 and perhaps other Yamahas like the R6 I’m not sure. I know Honda has used this method for a while now. But definitely not in 04. Yamaha came up with this technology that year so no one else had it in 04.

[@yeahok115sure]

@@jacobhendrickson8935 it was a cool time back then. I worked for Yamaha for almost 10 years. The 4 stroke technology from 2001-2009 was insane to be apart of. When Yamaha released the 2009 R1 in Vegas it was mind blowing. I got to meet and hang out with Valentino Rossi at the reveal.

[@yeahok115sure]

Cool you did this video. Not very many people know this is a thing!!

[@skinlab4239]

You would be surprised

[@jab-gn3sw]

There are two of us who know so far lol

[@MrChriskep1]

Good vid and interesting subject....thanks

[@mickeygallo6586]

In fact there where fractured rods in very old two stroke chainsaws like Pioneers and such, which had loose needle bearings...

[@jaydunbar7538]

They are stronger, it relieves stresses on the bolt so the bolt is less likely to break. Used in high revving performance applications, for the factory trucks your working on yes its primary for production cost. Now modify that cat to run 3500rpms at 3000+hp for sled pulling and that extra surface contact comes into play.

[@elvaqueroverga6980]

Some ISX 15 also have fractured rods. Very satisfying when you get them to perfectly Aline the cracks, when they are torqued.

[@w1ndex]

I wanted to say, "That's what she said." a lot watching this.

[@Rift45]

According to GM these rods debuted on the 1996 Corvette. LT4, last year before the LS-1

[@17th_Street_Preacher]

How do you crack a new one at home?

[@robertthornton7553]

Never heard cracked rod's as well explained. Well said 🏵️

[@deadline2k]

Every time you split the rod debris is created, you need to clean with a soft bristle brush and solvent, dry with compressed air. Also they should only be handled in 2 pieces or assembled and torqued to spec. I also read somewhere they have a limited number of times they can be split. I hate working with them.

[@AdeptApe]

Sounds like a bunch of reasons to hate them even more. One of the "benefits" on the Cat website mentioned easier installation by technician, not sure who wrote that.

[@jeffsimonar7161]

Adept Ape That guy also works in the sales department🤣

[@norman_sage2528]

@@jeffsimonar7161 😀😁😂

[@matthewstorm5188]

Another issue is that, if you use any kind of brush, the bristles can generate debris that can get stuck in the valleys - especially if you pack it in there by inadvertently stick the cap on before cleaning the surface. This, along with any kind of dirt, contamination, or physical damage, can cause the rod and cap to not mate properly.

[@joerangel611]

Josh Good evening Thank You for this video I did not think about the extreme care that these rod may need It is good to know all the details

[@ianplatts6233]

1978 Evenrude 9.9 has em

[@peterlogan1623]

explained very well

[@iBackshift]

Like #8 and the commercials havent ended yet. Just anticipation, haha. I put together a bottom end on a yamaha outboard 150hp and it had fractured connecting rods, fascinating.

[@Nudnik1]

Evinrude Johnson did this since 1970s.

[@iBackshift]

@@Nudnik1 Ive done snowmobile engines for 35 years and that was my first outboard crankshaft repair. Was fairly easy. I'll keep that in mind if ever happens again. very interesting experience.

[@larrytalley117]

Well.....I certainly learned something tonight...so fracture is not really broken...but broken can be fractured...sheesh my head hurts now.

[@macgyvermartin7347]

A square is a rectangle but a rectangle is not a square.

[@75LS1Vega]

GM has been using fractured rods on the LS engines since 1998. They seem to hold up fairly well there!!!

[@richardfrisbie252]

Cracked rods have ben around since at least the '70's. West Bend Engines used this process on their two cycle engine, needle bearing rods. This eliminated the the slight surface mismatch between the two rod parts and prevented failure of the needle bearing over time.

[@ct1762]

yea i have ZERO idea how he doesnt know about that. OMC (Johnson/Evinrude) had done that since atleast 1953 or so. this was clearly a necessity with the then-new needle bearing arrangement, but alot of 2 strokes back then still used plain ole' bronze ... which needed an absurd amount of oil. some where 16:1!

[@scottmccoy4129]

General Comment: Great job with your videos. You have an informed, educated, and well delivered message each time and it is very much respected and appreciated. Keep it up!

[@Nudnik1]

Out board motors and motor cycle s have used this for decades. OMC Evinrude invented this in 70s

[@ianplatts6233]

exactly

[@ct1762]

actually some in the late 50's! the big twin motors used them. same rods through early 70's, and one model made it to 1984 with the same basic rods (commercial 40hp). the rest were all fractured 1974-up as well. i rebuild these for a living. the only issue is when they went to precision-ground type over hand-sanded. a special alignment tool is need for the former. not hard to do with the tool, but many motors have grenaded themselves when some backyard tinkerer thought he could align them by hand :)

[@Nudnik1]

@@ct1762 I also built so many outboards in 80s-90s. Sad OMC gone . 👍

[@ct1762]

@@Nudnik1really is. such great motors!

[@am74343]

I suppose if you've got a V-8 engine, that you could use 4 cractured rods on one bank of cylinders and 4 machined rods on the other bank of cylinders. I think it would probably run fine without too much vibration. Or, theoretically, you could use fractured rods on cylinders 1, 3, 5 & 7 and then use machined rods on 2, 4, 6 & 8.

[@ALABAMAHEADHUNTER]

Another issue I have came across with a fractured rod is , if you have one that has fretted a bearing and you hone the big end to remove the bearing material it will male the big end to big . On some of the smaller diesel engine we work on they are beginning to make an oversize outside diameter bearing for this reason . Fretting is when the bearing begins to stick to the actual rod . Also you can not cut the cap and rod and machine the rod , they are not repairable .

[@Sgtyork488]

Hi..enjoy your videos alot....I have a truck with a 3126 and another truck with a C 15....just love these old cat engines...

[@PoliticalGangster]

I thought that fractured rods being a relatively new manufacturing process would or should somehow make the rods stronger. Today I learn that is actually not the case. It's just about a 30% cheaper method to produce connecting rods.

[@matthewstorm5188]

YES! If cracked rods were truly superior, aftermarket performance rods would NOT be machined.

[@Texas_Road_Warrior]

@@matthewstorm5188 there’s PLENTY of aftermarket rods that are fractured like this…

[@josiahkenn82]

Can you do a video on single turbo conversion kit..

[@RDC_Autosports]

ford went to these in the “modular engines”

[@deant876]

Thankfully I don't have to get that involved in the motors to have to worry about the type of rod caps it has. But good to know. And it was amazing to see the joint disappear like that

[@kevinhillgrenjr2248]

cars and trucks have had them since the 90s

[@wyattlandrath3265]

Your videos are my daily brain food

[@oldpete3153]

As in the past for many decades the cheaper costs to manufacture anything mysteriously is never passed onto the customer...in some cases these cheaper produced products will inevitably cost the end user more. Quality products are slowly becoming a thing of the past...Amen.

[@400outthedoor2]

Highly informative. Thank you very much.

[@garyr7027]

It goes back further than 2003, my 97 f150 4.6 has fractured split rods... they might go further back than 97?

[@Curtisbroughton]

Ive searched all your videos. Do you have a c15 water pump remove and install video? Not many out there. Just nuts and bolts?

[@AdeptApe]

Just uploaded a video which kind of shows it a little bit, but not specifically.

[@Curtisbroughton]

Thank you very much. Regarding the water pump, I was trying with the t-stat housing removed. I removed the front 3rd of the oil cooler to get the extra room required (like I saw in your video). Thanks again, you are the best!

[@itsFsmitty]

Adept ape, thanks a lot for all these videos! every bit of knowledge helps

[@paulattree1828]

Well I didn't know that.

[@daveostrom2908]

Did not know they existed, interesting info. Thanks

[@WhiteLinesBlueSkies]

As always, well done. I enjoying learning more about the CAT from your vids. WLBS

[@timwhiskerd2133]

Hi Joss. Very interesting. Thanks. Mercury ( outboard engines and some others ) used this principle. That was because they are two strokes and use Needle roller main bearings. The machined rod is impossible for this because you will always end up with a small step and that upsets the needle rollers. The Mercury rods were made from case hardened steels ( again because of the needle roller application ) and the case layer was deep enough to cover the entire fractured surface, therefore making it possible to fracture. These two strokes are ""normally"" rebuilt in "clean facilities and by high level technicians", so the fractured rod was quite successful. I have to say I was very surprised to see this applied to CAT's because as you correctly mentioned the mating of the surfaces can be problematic in the environment of heavy vehicle maintenance. I know all about this because I was part of the little team who working on the Cosworth Boat project and we had close dealings with Mercury. I'm a big fan of your YT channel and have learned so much about your work. Keep up the excellent channel.

[@AdeptApe]

Thank you for the comment and interesting information. Thanks for watching.

[@laputin710]

Hey Tim, can you please tell me how a step is generated in a fractured con rod given that they are handled perfectly as per the process. Can you tell me something you have experienced urself that specifically generates step in a fractured con rod.

[@ct1762]

@@laputin710id think its just an end mill that creates the grooves. trial and error i presume to get it right where they split perfectly.

[@ct1762]

wait Tim did you work on the 300 V6 back in the early 80's? always fascinated me that motor! i know they had cylinder liner issues or something and were low revving and relatively heavy so never really caught on, but must've been an answer to OMC's V8 motors dominating the circuits back then?

[@AndyL940]

Fractured rods have been used in OMC outboard motors since the late 60’s

[@donaldasayers]

One of the early Italian motorcycles, I think it was the MV Agusta had a four cylinder engine with a forged crank and roller main bearings, meaning that the outer races had to be in two pieces. The process involved cracking the outer races after cooling them in liquid nitrogen. Ford has been using cracked rods since the CVH engine on the Escort.

[@davidwalle5025]

Good video. How do you cut the rod cap and rehone the bore on a fractured rod like you would do on a machined rod, or do you not hone a,fractured rod.

[@Rote70SS]

The bore is honed oversized and larger OD rod bearings are used, if the manufacturer even offers them. On the Cat fractured rods, they are scrapped if the crank pin bore is out of spec or damaged.

[@mohammadalissa8255]

always great information and nice subjects in adept ape channel

[@raulpereyra2817]

Have you ever thought of HOT RODDING any CAT engines. You WOULD have the BEST knowledge.

[@stevek6921]

I don't know how long it took me to realize the fracture was designed and not caused by damage! Scratched my ape-sized skull for a few minutes there.

[@parmijo]

Honda R18a engine (used in 2006 Civic onwards) uses cracked rods. The rod and crap are forged as a unit then cracked apart giving the uneven surface. No positioning pins. It's a good and very reliable engine but in my experience no better than older honda 4 cylinders that use traditional rods. In 2012 they Honda updated it to the R18Z.

[@CarlosDominguez-ti4to]

Good video thanks

[@bobt5002]

Great video thanks for sharing.

[@parexc07]

In the brick business this is called a split face

[@phil23515]

Hey what do you know about the C13B. Are they thinking about putting some in trucks.

[@AdeptApe]

Looks like an industrial engine with an SCR system. Cat currently has no interest in going back to trucks that I know of. They tried (extremely poorly) with the Cat truck and then gave up.

[@doktorjonsson3860]

Is there any easy way to figure out which cap belongs to which rod? I have 5 extra rods for a boat engine and would like to use them, but when I bought the engine the previous owner didn't mark them when he pulled them out so I don't know which ones is a pair. They're the machined type.

[@AdeptApe]

Well, that can be tricky, you can look for etched numbers on the rods to identify them. If nothing else mate them together and measure the journal bore size. If it is specification that will work, might just want to get new ones though would be my recommendation.

[@doktorjonsson3860]

@@AdeptApe Yeah, might just buy some new ones... A boat isn't really a place where you want engine problems 🤷🏻‍♂️

[@rolandtamaccio3285]

Clean them, carefully tap tap them together, one at a time, do not torque, the parting line will only match on its partner, ( 99 percent of the time ), this a light tap tap, as soon, or if it doesn't go flush, try another cap . Also keep your eyes open for marks, and also the chamfer will match if correct . If you wanna go a hundred percent, after you do the former, torque them, and have a machinist check them for round and spec size .

[@Toolaholic7]

When the bearing goes bad,the piston rod is scrap and gets replaced

[@stefanocapomaccio]

I think they are older than 2003. Ford Focus 1.6 petrol engine from 2001 had those. I know because I melt my engine. 😜

[@AlfonsoMartinez-rq9oc]

Super informative

[@TonyGingrich]

Fractured rods are not a new thing. They've been standard for at least as far back as the 60's. I've rebuilt many automotive motors. Never once encountered connecting rods which were not fractured.

[@AdeptApe]

In the Diesel field, they don't seem to be as standard, they seem to be the exception from my experience.

[@longliner205a4]

Fractured cap connecting rods are a cost and time saving measure.

[@AngelaWest-if5ko]

I wonder who came up with this idea and how they figured out how to crack the cap?

[@jackdawg4579]

must be some fancy heat treatment going in to those to allow them to fracture the rod, then it not be to brittle in service.

[@norman_sage2528]

Annealing after breaking, no?

[@leokarasinski4217]

One other thing is that you can't resize the rods. They're one and done. Now I dont work on big diesel stuff so I'm not sure if that common practice on them. But on smaller engines it's common to resize rods by taking a few thousandths of the rod cap and then the machine it back to proper size to have a perfect fit for the new bearings. You can't do that with a fractured rod.

[@matthewstorm5188]

You have to increase the size of the hole and use thicker bearing shells (if these are available).

[@versacecondoms1501]

are there any forged fractured rods? this question is for an argument lol

[@ryelor123]

One disadvantage is you can't grind the rod and cap and then bore them out to the correct size if there's wear on them.

[@Vladgore007]

Also 're sizing a fractured rod is impossible. Entire rod with matching cap will need replacing... conventional rods can be 're sized as long as all weights are on par

[@matthewstorm5188]

Cracked rods are resized by increasing the large end diameter. Thicker bearing shells are then used.

[@Vladgore007]

@@matthewstorm5188 if you can find outer oversized rod bearings and obviously inner o size, because crank will be stuffed. As far as I know, only ancient air cooled beetle engines have both outer and inner oversized main bearings and not rod bearings as well. Never heard of other engines with outer oversized rod bearings. Besides, this will severely affect internal balancing of rotating assembly. So imo and what I always do... new rods, and be safe and know it's 100% without mods

[@cbmech2563]

My biggest question is what the process is to break them. Dip them in liquid nitrogen?

[@johngoldsmith6629]

kzbin.info/www/bejne/raaTdaSefpKqfdE

[@cbmech2563]

@@johngoldsmith6629 still seeing the fracturing process .

[@johngoldsmith6629]

@@cbmech2563 kzbin.info/www/bejne/eX2mqHucftt0g8k

[@ever4437]

If you really want to stir the pot. Most of the fractured rods are made from powdered metal that has been pressed at high pressures to make the rod. Thus the easier to fracture the cap off. Also cheaper to make. No problem for normal usage, but if your really turning a lot of rpms and high power, forged is MUCH better.

[@norman_sage2528]

Forged rods will bend before they separate. Sintered rods just separate and grenade the block. Sometimes the little things in life are important.

[@RustyorBroken]

2:20 Josh is secretly a bird. He's able to move his body while keeping his head perfectly still.

[@guyconnell2250]

All this time I assumed fractured con rods were "better" due to precise cap fitting. But the cheaper part makes more sense. Follow the money.

[@AdeptApe]

Don't worry, they cost the same to buy from the dealer, just costs the dealer less to make.

[@matthewstorm5188]

It seems like, whenever a manufacturer finds a cheaper way to make something that involves certain compromises, the marketing folks have to contrive a laundry list of alleged advantages to make the consumer believe they are getting a better product.

[@jasonsturm6922]

Love the video

[@christopherrasmussen8718]

I’ve seen them. Kind of made sense so I didn’t even ask

[@Mfgguy]

Rod caps and rods MUST be a matched set. In a large diesel engine this is critical. Fractured rods insure this. They won’t match perfectly if you mix them up, only if they stay together as a pair.

[@clayhebbes4224]

It negates a bunch of machining for the big end of the rod. Expensive tooling is why everyone doesn't do it.

[@stevedresen8497]

You can't size / resize a broken rod. They must be replaced when worn. I'd much rather have machined rods, the fractured rods are throwaways.

[@JA-fn7le]

This ISN'T a new thing, Deere has been using this for OVER a decade.

[@raginroadrunner]

Broken cap rods cannot be resized and reused. They are thrown away.

[@blacksmoke5009]

I hate fractured rods I prefer machined anyday! When you get cyl packs from CAT or Deere you really need to pay attention to what your getting I’ve run into this with a few KCB serial # engines thanks for sharing 👍

[@TheDustysix]

Fractured Rods are PM Steel.

[@pauljanssen2624]

One time rod had you heard the term Jimmy crack corn I don't care or Jimmy crack rod, yield to torque bolts yep it's for machine torque the bolts down at one time eliminating the person

[@richardjones4228]

Outboard motors have used cracked rods for decades

[@pdmustgtd1013]

Fractured Rods have been around long before 2003. Ford with 4.6 liter modular engine used powered rods so no special metal has to be used. They use laser to etch rod and split them apart. Machining big end of rod (bearing bore) no different than non-fractured rods. Parting surfaces on machined rod under load tend to work against each other (aka fretting). On fractured rod there is no movement between parting surfaces. As a tech working with fractured rods not down side, both styles you have to be careful with. If you did damage fractured rod parting surface in very small area you can hollow out that part. Only big downside to fractured rods if big end gets out of spec they cannot be fixed like non-fractured rod can be. I deal with fractured mains and rods not big deal too me

[@laputin710]

Hey, can please tell me what are the other reasons for step generation in a fractured con rod? I am currently working as a intern in a reputed car company, i have been working on this project but really I can't figure out how this step is generated, it's random and I have made sure the con rods are handled perfectly still this step is generated.

[@raginroadrunner]

If Cat does it, its because they saved 3 cents per rod.

[@terrelmchenry9524]

THEY STOLE THEM OUT OF A DODGE NEON.

[@chadmurfin188]

Absolutely. Chrysler has used them since 93.

[@norman_sage2528]

Sintered steel rods are cheap junk

[@Simon-nz8kt]

why 120 k sub

[@raginroadrunner]

They are cheap. Thats all there is to it.

[@Simon-nz8kt]

it is getting boringgggg

[@enginesandoutdoors3238]

Then find a new channel because some people are trying to learn about cats

[@ShainAndrews]

You know where the door is.

[@electric7487]

@@ShainAndrews G⊗ttem