Re-use rod bolts?

[miller]

A handful tossed up in the air...
Like anything else, just takes some common sense. But, for your understanding the rod bolt bit...at least at first, the rod bolt holes are cut precise, not only for fit, but more important line-up of the two halves. A loose bolt doesn't 'line-up' the two pieces right, too tight can distort the bearing hole.
A few things I've always done...first clean and deburr the rod, especially the bearing hole and the mating surfaces. I like my bolts to go in 1/4 to 1/3 the length, by hand, past that a snug, but light press fit.
Cleaned, check the bearing hole...needs to be round. Only if it's out more than .0002, would I 'resize' it. That involves cutting the mating surface, putting the hole out-of-round, and re-honing it back to size.
On and on...just needs to be right. Always also check for .001, or less pinch on the bearing halves.

 

[moper]

Don't mean to piss anyone off and this is just my opinion here, but I believe it's a gross mis-statement to say the bolts do not affect the bore. Having the right tools to measure and having the machine shop experience tells me that is incorrect. The only times the bores were not affected by a change in rod bolts, or main bores by a change to studs, was when exactly the same type of fastener replaced what came out.

Performance bolts are different material and manufactured differently in some cases, and when torqued properly and cycled WILL change the rod bore shape. Always. I've seen the rods bent because the bolts were hammered in without supporting the rod, and I've seen distorting by over-torqueing with a better fastener. This was a pet peeve of mine with 440Source connecting rods because they used ARP rod bolts and assembled the rods and machined them using engine oil - not the ARP lube. So when they were cleaned, lubed with the ARP lube, cycled, and measured - they were no longer round. Now they don't use ARP - but if you want they'll upgrade the bolts - without cycling or torqueing properly. So same issue...lol. Hence my (and most shops') recommendations for cycling and resizing.
It's not a huge income driver, nor are the other machining operations mentioned.

Factory machining quality is very easily improved on with an associated improvement in performance all around in power, lifespan, and economy by having all the modern machining done. Without question the investment in quality machining yields direct results from the moment the engine turns over the first time. If you wonder why two supposedly identical rebuilt engines from different shops have different qualities - that would be a big reason why. Ask your self why a shop owner would spend upwards of $100K to buy such equipment if there was no enhancement to the quality of the shop's product. The goal in performance building is to exceed factory quality - not duplicate it.

Read this:
http://arp-bolts.com/p/technical.php

The method of torqueing by measuring rotational torque to preload the bolts is not the most accurate way to measure the bolt's preload. Measuring the bolt's stretch is. So the idea that nuts are the "wear item" and cause for a torque value not to be met to can't hold water. Ever wonder why performance bolts of any make have dimples in the ends? It's for the stretch gage. Threads will wear in and lubricant will work it's way into the surfaces, causing the amount of turning or distance required to properly preload the bolt to increase. That's why new rod boles should be cycled once they are installed, PRIOR to measuring and resizing. Regardless of the measuring method a bolt's preload can be repeated unless the bolt itself was compromised (meaning overtorqued). Rod bolts do have a finite service life and that can be reduced by torqueing improperly. That means going too far and over stretching them. It's the body of the fastener that stretches. Not the nut. I've done it myself using the wrong torque spec or the wrong lube with the right spec. With ARP, if you use the moly lube and apply it properly the ARP spec is correct. If you use 30wt oil it is a different figure (higher) because the moly changes the coefficient of friction more than 30wt oil. If you use ARP lube on a factory rod bolt, using factory torque specs, chances are good it will be over-torqued and streched (mine were...lol). Bolt stretch gages are fairly inexpensive if someone wants to really do it like the bolt designers do.

 

[dvw]

I have personally changed bolts after measuring the bore with the Sunnen rod hone dial indicator and not seen enough change to worry about. A few tenths at most after bokt change. The holes were deburred and bolts pressed in , not hammered. We're talking replacement type bolts here of the same shank diameter.
Doug

 

[cdr]

I have personally changed bolts after measuring the bore with the Sunnen rod hone dial indicator and not seen enough change to worry about. A few tenths at most after bokt change. The holes were deburred and bolts pressed in , not hammered. We're talking replacement type bolts here of the same shank diameter.
Doug

I agree , but people are saying to get arp bolts & who makes an EXACT OEM replacement rod bolt ?

 

[Cranky]

From the link you posted.....

Installation Methods
"There are three methods that can be employed to determine how much tension is exerted on a fastener; using a torque wrench, measuring the amount of stretch, and turning the fastener a pre-determined amount (torque angle). Of these methods, use of a stretch gauge is the most accurate."

What about the rod bolts that don't have those cute little dimples? He's not building a race engine.....

No one pisses me off these days lol....but, what makes your experience trump the experience of someone else? I've seen plenty of shops spend big bucks on machinery that cost $100k but if they don't know how to use the ****, what difference does it make? For example, one shop returned a block to me with .003" out of round main bores and another shop did another block with .001 hour glass finish in the cylinders and both had state of the art machines. That kind of crap made me want to do as much work as I could myself. Most of the machines I got to use were old and worn. Who would you rather have do your work? I rather have a machinist that knows how to punch out great work using old machinery than the guy that can't do squat with new stuff? You have to know what you're doing with both but the one on the new stuff that turns out crap is just an operator. And my God, I didn't know those little dimples on the rod bolts were for a stretch gauge! I thought they were there because someone figured they would look better with them Hell man, I used to work in a shop that made fasteners.

Hate to pound my own chest but...I got my first machine shop job in mid 79 and by April 80 I started my apprenticeship and 3 years later I had my journeyman machinist certification. Yeah, I spent the better part of my machining years in a refinery but they also required close tolerance work on a lot of stuff. There's even many things out there that allow no tolerance. I've ran machinery from small precision tool room lathes to 84" vertical boring mills...horizontal mills, surface and shaft grinders, small and large and most of them were pretty old with some of the lathes having tags on them from Navy ships but it wasn't long before they started getting rid of the worn out stuff. We had one surface grinder big enough to put a small car on it's table. We even had a Sunnen hone. Very few people used it though. I guess they didn't see the value in it. Working the off shift had it's pluses too. Yeah, it wasn't exactly an automotive shop and we didn't have a Serdi valve machine or a CK-10 but quite a bit of automotive work was done there just the same. There were several of us that raced including one guy with a 56 Chevy that ran SS/O with a 265 ci engine turning 9500. It never blew up either. Imagine that....us dumb fuks doing crap work and making it last. It lasted because we were doing crap work. And how about seeing if you can find someone to prove to you that those little *** rod nuts do give up some even after the first time....

 

[Cranky]

I agree , but people are saying to get arp bolts & who makes an EXACT OEM replacement rod bolt ?

What does Mopar or Mancini have to offer?

 

[mopar 3 B]

Guess I fucked the last build up. A 383 with about 350000 miles on it. Everything was check at the time. Bottom end was last inspected after 160000 miles of some times hard road use. Rod and main bearing still look almost new and clearances still within spec.
Other than machine work new valve train and new oil pump the bottom end now is at 500000. The bolts have never been changed.
Is this just dumb luck or a testimate to Chrysler's quest for quality?

 

[miller]

Damn, Cranky! Hehe...sound like a man after my own heart!

All very well said, including from mopar 3 B. I'll toss in, I'm not trying to piss anyone off either. If there's things you believe in, stay with it, just like those rotten little bolts I have no problem re-using.
When I picked up that set of ARP rod bolts, didn't take long to figure it out. Some would not even think about going in. Big hammer go to hell, or big press, or anything else.
It would have taken a precise reaming job on the bolt holes, to get a proper fit. Stock is good enough for government work! Even if you have to swap 'em around, to match up the fit...so what...all day long. There's machining tolerances in damn near anything you pick up...within reason.