i have eagle rods with the arp 3/8 rod bolts, they have only been use once, meaning i loose up the rod bolts, took off the rod caps to check the rod bearings, are the rod bolts still reusable?

 

Iv reused them several times.

 

I personally replace rod bolts every time they come out

 

i've reused them a bunch of times on rod sets during rebuilds or refreshes with 700+ minimum horsepower, Always torque them correctly and accurately. Stretch gauge is best, but a good torque wrench has never failed me. They are high quality bolts, not home depot crap.

 

this is true but they become crap if overtorqued. i'd say as long as you kept the preload on them at or under the specification, you can reuse them.

 

ANY bolt becomes crap if overtorqued. Im sure ive over torqued a set of arp2000 by a few pounds but still ive reused them a good bit.

 

wel im not sure how much the person who build the motor torque them to, but i called him asking for how many pound they torque the 3/8 rod bolt and they told me 50lbs. so i just retorque them to 50 pounds.

 

50? they are rated for 43 on moly and 60 on 30weight.

 

They aren't a torque to yield designed bolt..... you can re-use them as long as they have not been torqued/stetched beyond recommended specs in previous installations. Use a stretch gauge and recommended assembly lube for proper stretch/pre-load on rod fastener's.

I'd ask for a bolt stretch measurement instead of a torque number.......

 

ive definately used them a few times with no issues, 43 ftlbs with the moly. ive actually had the same rodbolts in the same eagle rods on the same oe ls crank in the last few motors ive done, probably 30,000 miles on 400hp

 

I get a kick out of people saying they buy new bolts everytime they loosen them up and have to retorque.

I am not an experienced engine builder, but I have worked on aircraft and have torqued some very critical bolts on military planes. Certain critical bolts were not replaced everytime we took them out. Im also positive that some of those bolts and hardware saw more torque than what was recommended, and I never saw nor do you ever really hear of a military plane going down because of maintenance.

With that being said, I would reuse bolts. I have in the past and never had a problem in my car or any of the aircraft I ever touched.

 

If you are using a stretch gauge that means that bolt has been torqued to its yield. I wouldn't reuse any bolt that has been torqued to yield on any internal parts of and engine regardless of quality.

 

no

 

How about you explain why you disagree with me rather than just a one word answer. You can use bolts if you measure them and they haven't stretched over X amount over brand new. I still will not use bolts that are torque to yield and by my knowledge if you are using a bolt stretch gauge that bolt it torqued to yield. Even if you measure it and it's within specs, I still wouldn't risk it, but that's just my .02 and experience.

 

So you're saying that just because a bolt was stretched while being tightened that it has "yeilded"? Every bolt will stretch even with relatively low torque applied to it. If you put a stretch gauge on an arp rod bolt and torque it to 20 lb/ft you will see it stretch, but that definitely does not mean it is trash. BTW those effing stretch gauges suck for these arp bolts because the anvils don't fit properly in the dimples in the bolts. If you really want accurate readings from them you have to make your own anvils to fit snuggly.

 

Correct me if I'm wrong but when you torque a bolt to yield that means that you have put the maximum amount of tension on that bolt that will not cause a failure. By doing that, if you have pushed the limits of that bolt once, why would you do it again. I doubt ARP is going to give you some bogus stretch number that they think will just keep the rod cap together. I'm sure the figure is the maximum torque that they were able to apply and still have the bolt not be weakened by over tightening

 

I can draw a graph later tonight to help explain if you want, but the stretch specs you get with a rod bolt still keep a bolt in it's elastic stage of tension, which is the goal for all rod bolts and is why you want to use bolt stretch and torque over just torque. TTY bolts are torqued beyond that into the plastic stage of deformation which cause them to not be able to return to stock length and are on the very edge of snapping..ie the yield part. Typicaly OE manufactures use these for head bolts because the crushing of the headgasket.

 

Im not going against what any of you are saying, but if this type of torque where it turns the bolts into a "plastic stage" of deformation was really that critical, then why is so much hardware reused? I recently talked with someone who is regarded as one of the better engine builders/machinist out there, he suggested reusing alot of the stock hardware that others are scared of using. He also stated that he has never really experienced any sort of bolt failure either, when reusing hardware. I have reused stock headbolts, stock rod bolts, aftermarket rod bolts, ARP headstuds, etc. Never have I had a bolt failure, nor do I really know anyone that has. This was the same on military aircraft as well. The planes that I worked on, the hardware was torqued on a number of times. Some of these bolts were crucial for the aircraft. Engine mount bolts, bolts through out various areas in the landing gear, flight controls, etc. Never did I see a critical bolt fail in that either. With the top fuel cars, I bet they reuse quite a bit of their hardware and its torqued on numerous times.

Like I said, Im not going against what any of you are stating and I totally understand how and why a bolt stretches. I have seen some bolts that have been stretched, but it was because of negligence on the installers part. They were over-torqued from the beginning.

 

When I worked for Caterpillar we had issues with 10.9 grade bolts used for injector hold down clamps. There was a service letter to replace them every time they were torqued even if just to seat the injector. The eventually upgraded the bolts to 11.9's and still had problems with them

 

I have a couple friends that got out of the military and went to work for Caterpillar. Both of them were diesel engine mechanics in the either the Air Force or the Marines. Anyways, they both told me about some of the training they did with Caterpillar. It was some in depth stuff, it seemed?

Do you think these bolts failed because of the stresses they saw while in use on the engine or because of failure due to the torque that was applied during installation?

 

This.....

 

Whenever I replaced injectors or did a rebuild I always used the old bolt to seat the injectors and then used moly paste on the threads of the new bolt, and both surfaces of the conical washer. I never had a come-back and this was with 4 years of service with them. I did though have one that broke while I tried to torque it. Brand new bolt and I could tell that it was stretching, so hard to tell I guess?