Yes OEM is at a set standard but if you want to go the extra step and get the best for your engine getting the rods and pistons balanced is a good way to go pressed fit may be different in how they are balanced that may be true but even then getting them balanced is a good idea if they can be done I don't see why not.

It hurts nothing but could get you some great benefits if done correctly.

Balancing only hurts your wallet not your engine some people go the extra mile some don't

I always installed custom forged rods in my engines. The 4.7 this may not work every engine is different do some research if this is something you think you may want done is all I will say.

 

The metal cannot be machined on the rods. That's why. Hence most likely why they are cracked at the joint for the bearing instead of cut. And why they are not threaded and have a thru bolt. It is a pressed forging. Very accurate in duplicating weights of connecting rods.

I don't see how you can tell someone to balance an OEM crank with OEM pistons. Unless your profile is wrong, you don't have a 4.7, just saying. 2.5, 3.9, 5.2, 5.9 is a whole different animal than the 3.7 and 4.7.

I am not saying I am always right either, so please if there is documentation out there regarding the procedure to balance a stock 4.7, I would really like to see it. I researched this extensively when I was doing my teardown and balancing was not an option on rods and pistons.

 

Most machine shops should be able to tell you what is possible or not and no I'm not talking about my 2.5 they are pressed on also

All I'm saying is it doesn't hurt to look into the possibility

Any crank can be balanced

OEM tolerances are ok good but not perfect good

 

Sorry I was editing while you were posting. I know, pressed fittings for the rods is different than a pressed forging of the rod itself. If you call a shop they will tell you the same. It just isn't a possibility is all I am saying, I made the calls and worried myself to death over not being able to balance the pistons. When I weighed the pistons on a scale they were all identical. Within less than a gram of one another. The newer tolerances in machined parts is amazing. In fact, if you mic out the bores, you have to have be able to go over an additional decimal point in comparison with the older magnum engines.

This blew my mind also when I came acrossed it. Also blew my mind that the connecting rod bolts are TTY and the head bolts are not.

I had to walk away from a lot of machine shops when working on this motor because they themselves didn't know what they were doing. If you call a shop that "specializes" in the 4.7, and specifically ask if they replace the connecting rod bolts after changing bearings, most will say no. When in fact, this is actually in writing in the FSM. Not just hearsay or something learned through trial and error.

 

I guess most people just have a shop do the work or just swap out engines rather than do the R/R themselves.

It has been many years for me that's for sure

I know a good machine shop is hard to find especially in AZ in southern California we had some great shops to go to

 

Good machine shops are becoming hard to find everywhere. Here in Chicago there are shops, but good ones for precision work like the 4.7 are difficult to find. It is becoming a lost art.

In my experience with the 4.7, most shops treat it like every other engine they have worked on and it isn't.

 

Well you have the experience so I will go with you

 

Im just curious but what other differences have you come across on the 4.7? I have one and have about 120k on the clock. Just wanna be as knowledgeable as I can

 

I'm gonna resurrect this one more time for future reference.

Dodge 4.7L 'N' engine was blown to hell and back. Broke one rod, damaged 5 more (bearings welded to the big ends), broke the block in two places (bottom of 2 cylinders), another cylinder cracked vertically midway down the bore (probably the cause of the entire misfortune), crankshaft damaged way beyond repair.

Anyway, back to the rods: They're sintered and cracked, so typically there will be no machining on these although I've had some old-timers say they've done it. The problem is a way to hold the cap in alignment using a precision bolt and the through hole honed for a precise fit. Not worth it, in my opinion. Clean them up and use them as is. Mine have a bolt that passes through the cap and threads into the rod.

Bolts: There are two issues here - replace or reuse. I always replace but I've found two conflicting schools of thought. The bolts are TTY or the bolts are TTA. If you consider they are torque to yield then toss 'em. If you consider them torque to angle then check for stretch or deformity and re-use if there is none. Problem is that I consider both sources of information reliable. By the way, the new bolts with the superceded part number have a locating collar on the bolt above the threads.

Weights: I've collected several used rods from several sources and found that the variance is a maximum of 3 grams. I've paired them up by weight and the pairs will be installed on companion cylinders. Sounds good, should work but it's an experiment.

Last thing: If you work with Mopar original parts then you're stuck with what they give you to work with, like the rod/piston assembly or the variance in the bearing sizes. The crankshaft and cylinder bores can be machined for everyday pistions and standard undersized bearing with no problem at all. In fact, the replacement bearings and materials are better than stock. A good crank grinder will give you perfect measurements across the crank to be used with the aftermarket bearings. There's only one minor problem to deal with using the aftermarket pistons. The piston pins are usually .001" bigger than stock. I don't know if this is for a better, tighter fit in the original rods or if it's expected to hone the small end for the bigger pin to match the spec for the interference fit. I'm not going to hone the full .001" but I will clean up the hole just a bit to make sure it's straight.

New post to an old thread but since these engines appear to self-destruct on a regular basis these days I though I'd post. Used 'N' engines with 180K miles are selling for upwards of $1800 and reman from a good supplier twice that. Ridiculous. Makes me want to stuff a late model GM engine and trans in it for way less than that.

Have fun.