Automotive Connecting Rods 101

[watajob]

Thank you sir for another informative video!

[fd2mugenRR1]

CAN i come to work for you...??? your are an absolute master on these things...

[FlatAbove732]

Fiatnutz this is a great video. I'm wondering though. I assume that I have the type of connecting rod discussed as the 4.6L Ford and I have read from time and time again that if I use a supercharger, I should change over to forged connecting rods. What is your take on that? It looks like from your video that the 4.6L ones are good but you do mention that they can fracture. the forged ones look stronger to me, from just looking at them.

[fiatnutz]

@FlatAbove732 - Get a set of forged or billet rods for use w/huffer.

[ArcticSTi]

I love all these videos about Costa Mesa R&D. I learn more and more...

[ratrace2p51]

OK, so what will tell me the "right" direction to install the rod.

I don't see anything in the Haynes manual, or onthe web in general.

Can you send me to a picture some where that will show the orinitation of the rod.

[ratrace2p51]

Is there a front and a back to a connecting rod?

Yesterday I tore down a Chevy 2.2 LN2 and I noticed that the rods are not symetrical.

they have a "sort of tab" on one side but not the other?

[fiatnutz]

@ratrace2p51 - Yes, most rods go in an engine in a certain direction and you have to be mindful about how they are installed.

[josiqvideos09]

@fiatnutz Hi man great video. I have a question for you: I have a 4G94 SOHC Lancer 2.0L this Lancer it comes with Forged Steel Rods but they are like the number #1 rod (from left to right of screen) at 4:00 comparison, so they looks really thin, but they are forged steel by the japanese mitsubishi factory...

(comment continued)

[josiqvideos09]

@fiatnutz ... and recently I turbocharged my engine and I set to 11psi like (200hp) on t3t4 on those stocks rods, and they holds it perfectly; my question is do they kind of rods holds 18-25psi like (350hp), or I need some H billet forged rods like #4 rod in the comparison at 4:00??? My engine gears redline shift is at 6,500rpm Thanks.

[dragsteralf]

so power metal rods are stronger then forged rods? i only ask because you said the powder rod has a higher rpm limit.

[toyota1212]

hi great video... very informative ! i have a couple questions, you said the h- beam are the strongest but you didn't give them a rpm range... what would that be? also I have been looking into rebuilding my engine and finding shops to do the work and the one i found has a couple options and one is an upgrade from h-beam to i-beam why would i "upgrade" to i-beam? arnt the h-beams better? but there saying it will be an extra $400 for i-beam rods instead of the h-beams

thanks for the vid!

[tiddlywink100]

Nice discussion on connecting rods...I always learn a lot when I watch these videos! Is there much usage of composite rods like carbon fiber and do you see exotic metal rods like titanium or other metals? Thanks again for your informative videos!

[fiatnutz]

@tiddlywink100 - No carbon fiber rods yet, but I do see a few titanium LS7 rods. I'm glad you are learning from my videos.

[k9forkids]

I always assumed that H-beam are the strongest but was told by an engine builder that some High dollar Forged Rod like carillo/Oliver was stronger, of course not taking in consideration of Alum Billet and Titanium

[20rich02]

Thanks for posting and also alot of thanks for your knowlege that you share with others. what i liked about your vid is that it wasnt to much or to less infos. just right to tag along with and to remember.another thing i liked is that your report was on one subject but which includes all types. Keep it goin guy, take care.

[brendanraymond]

what are those huge chucks of material located on both ends of the forged rod? ive seen them on a quite a few other rods but i havnt been able to work it out.

cheers

[fiatnutz]

@brendanraymond - They are factory balance pads used to adjust the rod weights on both big and small ends

[brendanraymond]

@fiatnutz thanks mate

I just find it suppressing that they make them so big... I wouldn't imagine that would be very good for keeping inertia and rotating mass down. Does the density in the steel vary that much that they need to be that big? I’m guessing this process would make the counter weights overly large?

So I'm guessing they'd be the first to go with modding a rod. Why don't they just balance their rods the way you do from the factory? Expensive?

Thanks again for the reply!

[brendanraymond]

I really appreciate you uploading all of these vids... it answers alot of questions I've had that I was either too busy at the time to ask or just embarrassed to ask them completely.

I tip my hat to you

good day sir

[flipmodeOptimus]

Nice Video for a Junior Mechanic three years after tuition and fresh on the scene!! Nice going John :-)

[highdeserthater]

dude what would happen if someone made a kevlar connecting rod? lol that i think would be WAY cool wouldnt it? or is kevlar not heatproof.

[youdragon]

would cam bearings cause lack of oil psi??? on my 97 sierra 5.7 litter v8? when its cold at start up i get over 40psi but has the engine warms up its drops down to about 20psi when idleing and then goes back up to 40ish my driveing is that the cam bearings or rod brearing that are causeing that? and how much would it be to reaplce each or those???

[fiatnutz]

@youdragon - I suspect that your cam bearings are at fault. You will need to remove the engine and completely disassemble it to make repairs. Installation of the cam bearings runs around $45, plus parts.

[youdragon]

@fiatnutz how can they be checked without removeing the engine?

[fiatnutz]

@youdragon - Checked for what, exactly? Housing bore size, pin bore size, c-c length, bend twist, what?

[craigcbang94]

@fiatnutz ya actually i have the same problem, i need to check if it twist and is the reason why my engine is frozen. i believe i can drop the oil pan a bit and look up in there. but how can i drop the oil pan without taking out the engine completely? on a 99 crown Victoria p71

[SoLSamuraibloodblade]

@youdragon it is normal for higher oil pressuer during cold start up

oil is cold and much thicker than at operating temp

and 20 psi is fine on an idling engine

and as u drive revs are higher so naturally more oil pressure

[scotts439]

John, given the choice between common heavy duty "X" rods in a street/strip motor... or the newer production powdered rods; which would take more abuse? Also, are the PM rods conducive to beam polishing, fitting with ARP bolts, etc the same as the stockers?

[kalam518]

hi, awesome video and explanation.

My question is :

when someone gets a "rod-knock" what part of a rod goes, how does it go and what causes the constant knocking noise?

How come an engine still runs without it (or does it only run on the functioning cylinders)

Can A rod be replaced without taking apart the whole engine?

many thanks guys

[highdeserthater]

@kalam518 if your rod is knocking it could be the bottom or top bearing. it means that its loose and could break and fly out of the block!! and that is not fun. if you have a rod knock you have to take it ALL apart to replace the crank and the rod that broke. if you have that you may aswell just do a complete rebuild. not that expensive if you do it yourself. but unless you have lots of experience thats not a good idea. :)

[kingtipz]

question about big end: how can u measure the "roundness", and also how would u determine the appropriate rod bearing size of the big end is altered

[fiatnutz]

@kingtipz - I use a AG300 concentricity gauge to measure roundness, housing bore is also measured at the same time or it can be done with a pre-set dial bore gauge. Pretty simple when you have the tools.

[youdragon]

ok i asked a Q about oil psi and this is what i got and im lookiing for a s2nd opnion

[yvesgia]

.875' tick Titanium 64AL4V

This is right stuff?

On my actual carillo rod I have Bronse boushing that need be repeted to titanium rood? Aluminium rood can make the job? Tank You Yves Giard

[yvesgia]

Can I make my rod from titanium Plate?

[fiatnutz]

@yvesgia Depends on the alloy and how thick the plate is.

[bsoth]

FORD RULES! Don't change a thing John!

[lespaulfan4]

thanks for rod tips

[AnathemusVideos]

What engine from chevrolet actually even runs past 7,000 rpm?

[subiemon]

corvete, camaro, 572, 604

[digzie1]

built or factory? if built ,they all can go way past 7000 even big blocks..

[james3000gt]

69 Z28, I've had my 302 up to 8,400 RPM.

[2800aaa]

thank you for telling the diference

[politowic]

Nice video. I rated your video after watching it. I am running a marketing campaign to start a large auto detailing chain corporation.  Let me know what you think by checking out my channel. Thanks

-Politowic

[RexB]

That was awesome! I love learning about engines!

[boxer3main]

a real forged, you would think would be close to billet in the rpm range...

[bastec666]

billet is always best IMHO because its a solid piece instead of 2 pieces put together or hot liquid metal pored into a mold. billet is always better. :D

[subiemon]

no forged is if u ever watch how they forge something u would know, and billet ok but not the best, like he says forged machined :-)

[bastec666]

billet is a solid chunk of metal cut down to said item. so you take say a slab of metal and cut it down to a rod using cnc machining.

forging is when you compress that metal, changing the shape. It compresses metal molecules and changes the grain, which is bad for metal.

What you refer to, forged machined, is like with rays racing rims. They forge then machine the left over for roundness accuracy. It makes the metal lighter, but that also means they are easier to break.

Learn your shit...

[subiemon]

forging does not compress is re-structers or changes the grains pattern making them stronger!!!

[dimman77]

@bastec666 Erm... Maybe do some research on what heat and pressure of forging do to metal grain then come back and fix this post...

[bastec666]

@dimman77 im not wrong, in anyway, by smashing the metal into shape you compress the metal at the same time making it weaker. when rays racing makes rims, they don't take hot metal and make a rim, its you generic ready to go slab of meat, and they compress it to the rim shape, and then cut it to exact shape, it makes the rim super light but it also breaks easy, hence when you buy rims that are circa 10 pounds or less they break so fucking easy.

i will correct nothing.

[dimman77]

@bastec666 Well you are so far from reality in your statement that I have to conclude that either you are a troll, stunningly ignorant or amazingly stubborn. Either way there is no sense in me continuing this discussion as banging my head against a wall would be more productive. Like I said before, research.

Cheers,

D

[ITRlover1]

All those rods have such a low RPM tolerrance? I rev my Integra type R to 9500 on stock rods with no problems

[originaldriver]

stroke has more to do with rpm tolerance than rod designbecause stroke determines the piston speed at TDC.

The connecting rod is under the most stress when the when the piston is halted at TDC after traveling to the top of the bore.

This sudden "halt" at TDC generates tremendous forces on the rod and the rod bolts.

Most well-built street performance engines will perform safely at 4000 ft/sec of piston speed.

Use this formula...

max rpm = (max piston speed X 6) / stroke

[drums4life555]

your stock itr rods are probably forged, right? i think these rpm is not as relevant personally, obviously the stroke makes the huge difference. like bikes that can go to 12k rpm probably have forged rods.

[ITRlover1]

I dont think they are forged but they are stronger than your average rod somehow

[Joe11Blue]

Yes, and you still drive an overpriced slow econobox.

[ITRlover1]

lol whatever makes u sleep better at night fag.

[firefox8192]

does polishing and ballancing forged rods help any. please advise

[fiatnutz]

Balancing is necessary, polishing doesn't hurt either.

[originaldriver]

Yup....

Shot peening and better rod bolts will increase fatigue limits as well.

Remember,.. the rod is stressed the most at "TDC" during the exhaust stroke. Its literally being stretched.

[michaelovitch]

@originaldriver

As said in the vid that's why the lighter rods stay round more time than the others more heavy.

But it depends if the engine is NA or turbo too.

the stress is not the same on those engines....

[zabcod]

honda b series engines go 8000+. what rods do they use?

[humantestdummy]

forged h

[crxlover83]

wrong. they are forged I beam rods

[smithraymond]

Sintered is crap. Forged much better.

[marek0086]

one Billet Rod can take 1200hp???

[dfentono]

Thanks John, good stuff!

[LeeEBranch]

Copper is superior as re. dissipation of heat and it is used on some rods for this reason.. These copper 'small ends', in some applications, have been designed to operate without any bushing. 'Rod ratio' is very, very critical in determining torque to be available at a specific RPM range~ Are you conversant with the Hepworth-Granger formula?

(Worked for Freddie at one time)

Can you do Triumph 650 m.c. heads?

Nice work~ You are most generous in sharing your knowledge.

[timsamuels1971]

vary cool john

[paulmerz]

Very informative video, as always John.

Thanks.

[aleshits]

Hi!

Im repairing a fiat 500 engine, im a little amateur on this things, can you tell me how much LBS do I have gine to the connecting rods.

thanks!

[tmedhat]

very helpful

thank u medhat from cairo egypt

i have a workshop 2 rebuild car engines

i enjoy all ur posts

[305Bowtie]

A++ video. You just earned yourself another customer from San Diego and I look forward to doing business with you guys.

[44marcos44]

VERRY HELPPIFUL

[GSxcsubroto]

what about titanium rods.?

thanx

[fiatnutz]

I didn't have any in the shop at the time I made this vid. Ti rods are really good and can spin to extremely high rpm's, they're just expensive. JE...

[GSxcsubroto]

man..thats was cool video, ..i need that..thanx alot,

regards.

[garnita0]

question....how can the billet rod be forged and machined? is it forged then machined or is just machined from a billet?

[Isetari]

it is forged in a form and after that machined

[masterchief377]

Thank you sir. This video has answered questions that have been bothering me for quite some time. It's a whole lot easier to learn when you can hear the tone of someones voice, not just their typing.

[wzrox]

nice video

i live in holland,and i like these video s

i also think you re a good teacher!!!

[pokerdotjearsy]

thank you very much, its nice to see such a clear, informative and professional video on engine internals

[enginemasterbuilder]

ABSOLUTEly perfect vid . great refershment of whats going on in the life of engine rebuilding. have you had any 440 dodges in laely where 5,6 cam journal has turned in its bore and blocked the oil off to that area of the engine?

[fiatnutz]

Not lately. Did the bearing seize to the cam? What did the journals look like? Sounds like it's time for some green Loctite. JE...

[enginemasterbuilder]

that happened about a year ago.probably a bad idea to pein the bore of the cam galley , however it worked. i think the block had a little bit of core shift.

[enginemasterbuilder]

yep John knows his engines

[RanchoTitanOR]

good vid