Changing Connecting Rod Bolts.

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Dragonbat13

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I got a 5.9 Magnum that I want to put new rod and main bearings, along with rings, oil pump and timing chain. I just want to freshen up the engine before I install it. The cam and heads are stock, but the pistons are .040 over sealed power pistons, and the rod journals are .010 under. I got the engine last week out of the u pull it, so I dont know the history of it. The truck I pulled it out of had a digital mileage setup, so I dont even know how many miles were on the truck, much less the engine. Only thing I do know is it was a 2500 and it didnt seem to look like it was abused super bad. Visual inspection of the bores look fine, still have the crosshatch in them, and the piston skirts dont have much, if any wear.

Anyway, I am worried I should change out the rod bolts. The pistons are pressed on. Most of the aftermarket rods are full floating, so I cant really use those, with the current pistons. And I want to avoid the costs of a rebalance also.

So, do I really need to worry about the rod bolts? Right now the engine is just going in to get the car moving. But I will push it some when its in. Probably no drag strip, but who could keep from hammering on a magnum smallblock in a Dart Sport?

If I should worry about the rod bolts, what would be the cheapest route? I gotta save money for other parts of the car. If I get something like the EAGLE press fit I beam rods, will I have to have the rotating assembly rebalanced? That may not be the cheapest, but I think it would be the best route for the money, as long as a rebalance isnt required.

What would everybody do in this situtation?
 
Ok, so it is cheaper to get the pistons pressed off, bolts changed, rods resized and pistons pressed on?

What are you considering a rod reconditioned? I am thinking install the new bolts, check and resize if necessary. Am I right?

I would go this route if the total costs was under 175 dollars. What is a fair price to have rods reconditioned with new bolts installed, if I supply the bolts? Seems to me that in my town machine shops are overpriced. But houston is two hours away, if I have to go there.
 
Cheaper is not the direction to go. Doing it correctly so you don't spin a bearing and ruin a engine is the way to go. If the old bearings look good and evenly worn it would be better to install new bearings and don't replace the rod bolts. tmm
 
When I say cheaper, I mean cheaper than getting new I beam rods. Usually its more cost effective to get new rods than it is to recondition old rods. Thats what I meant by cheaper. The thing is that I want to avoid the costs of balancing. Add that, and then it is less money to just have the bolts changed on the old rods.

Just wanted to make clear what I was saying by "cheaper".
 
Dragonbat13 said:
When I say cheaper, I mean cheaper than getting new I beam rods. Usually its more cost effective to get new rods than it is to recondition old rods. Thats what I meant by cheaper. The thing is that I want to avoid the costs of balancing. Add that, and then it is less money to just have the bolts changed on the old rods.

Just wanted to make clear what I was saying by "cheaper".
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Resize what you have,unless you want a really solid foundation for 500 + horsepower.(not a bad idea,considered your budget). New rods,means a new "bob weight",and a crank rebalance. (Somewhere in the 300-600 dollar zone,I.M.O). What do you want it to do?
 
One part of the equation that we don't know is how much your machine shop will charge to change out the bolts and recondition the rods vs. buying new ready to go rods. That's where the cheaper comes in. Did you get a estimate?
 
I am just doing a basic rebuild of the engine. Even the stock camshaft. Only mods will be a dual plane intake, four barrel, recurved distributor, headers and dual exhaust. With a 904 behind it, 3.23 gears in an open 8 1/4 diff. From what I have read it should be about a 300 horsepower engine.

I suppose I will just have the rods I already have checked and resized with new arp bolts.
 
So the engine you just bought, you pulled apart? It already had .040" over pistons in it?

What do the cylinder walls look like as far as wear and crosshatch?

If as mentioned above, you are just doing a basic rering and the bearings look good, for a daily driver with no intentions of beating it to death I would just run the rods and bolts as is.
However, if you intend to beat on it you might think about new bolts and resizing the old rods or new rods.
 
Dragonbat13 said:
I am just doing a basic rebuild of the engine. Even the stock camshaft. Only mods will be a dual plane intake, four barrel, recurved distributor, headers and dual exhaust. With a 904 behind it, 3.23 gears in an open 8 1/4 diff. From what I have read it should be about a 300 horsepower engine.

I suppose I will just have the rods I already have checked and resized with new arp bolts.
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Good plan with your combo.
 
Ask if they will change the bolts with the pistons on. If not, you may be buying a new set of pistons as well. Its not a guarantee that they will not break a piston pressing it off the rod.
 
Nuff said.

[ame="http://www.ebay.com/itm/Mopar-SB-Eagle-SIR-6123-CP-Connecting-Rod-Set-I-Beam-NEW-FACTORY-BOX-8-matched-/160811709000?pt=Motors_Car_Truck_Parts_Accessories&hash=item25711ff248&vxp=mtr"]Mopar SB Eagle Sir 6123 CP Connecting Rod Set I Beam New Factory Box 8 Matched | eBay[/ame]
 
Would those eagle rods require a rebalance? That was the rods I was considering instead of new bolts, since they were press fit wrist pins. Even if it costs a little more to go over to the eagle rods than the bolt change and resize, I think the extra money is worth the piece of mind. Just dont want the costs of a rebalance.
 
I would imagine the Eagles are a different weight than the stock rods and would require re balancing. Let me see if I can find the weights for you. tmm
 
I found that the Eagle rods are 605 grams and the stock rods are 758 grams. A lighter rod is good but it would need re-balancing. One good thing is that weight would be taken out of the crank and that is cheaper than adding weight which can get expensive. tmm
 
toolmanmike said:
One part of the equation that we don't know is how much your machine shop will charge to change out the bolts and recondition the rods vs. buying new ready to go rods. That's where the cheaper comes in. Did you get a estimate?
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My guy wil recondition the rods for $30 per rod, or $240 a set.


It' works out to be about $40 more than new rods, but I like having the squirt holes in the old rods.
 
Dragonbat13 said:
Does he supply the bolts?
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No, you have to get them from Mancini.

http://chucker54.stores.yahoo.net/arpaenrodbol.html


I like to have the oil squirt holes. The new rods do not have them. It works out to be about $40 more to recondition my old rods, than buy a new set, but I will rather do that and keep my oil squirt holes.


The oil rings will take care of any extra oil, but they cannot correct for not enough.... :violent1:


I like durability in my engines.... :farao:
 
As Rusty has already expressed, it's cost effective to just replace the rods, and upgrade the pistons to say a KB107. Either run what you have, or upgrade everything.

It's black and white like that.

I stayed with the old; quick re-hone, new rings, new bearings, old rod bolts +1. Hell I've got a bastard piston in there, runs and revs clean and fast. I tried to find a reason to worry, but once it starts and runs, all that melts away by the way it sounds when it runs at 3500+ rpm. These bottom ends are tougher than they are given credit for. Check out JoeDust451 and LXguy, both great examples of clean it up and beat on it.

Now if you want to spend money on it, then go right ahead and get new rods and pistons, the deck cleaned up with new bushings; and all that other crap that adds up to about $5-700 worth of machine work. My opinion, both will be 'durable'. You can just squeeze a little more power and piece of mind out of the latter, good ruck!
 
I have no direct experience with Eagle SIR rods but I have heard from numerous sources that they are crap. You got this engine at a Pick-a-Part. The engine you have is stock except for .040 overbore, correct? And you plan on keeping the stock cam and heads. Stock 5.9s are not known for breaking rod bolts and breaking rods. IMO, I would leave it alone.
 
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