hondaapi

Hello guys.

Some weeks ago I sold a set of Eagle-H-Beam rods (with3/8Arp2000rodbolts) to a customer of mine.

Yesterday he told me that this was his first block he ever assembled. He also told me that he torqued the rodbolts to 59lbsft instead of 43lbsft that are suggested on the sheet.
I told him to replace the rodbolts but he donīt want to do it. He believes that more tourque is better.

What are your oppinions?

EnzoSpeed

Well, proper stretch is usually achieved by going well over the listed torque spec. That's simply due to our inability to recreate ARP's ideal laboratory conditions when using their bolts in a real-life situation.

However, tightening them too much might ruin them. Since I highly doubt the bolts had their manufactured length measured with a micrometer prior to installation, it's impossible to test for permanant stretch at this point.

So basically, they might be good, they might be bad. It depends on a lot of things. Unfortunately, at this point there is no way to figure out if they're bad. If it were me personally, I would replace them to be safe. I'm sure any competant engine builder would do the same.

hondaapi

Well, that what I think too. I usually mesure all my rodbolts before intallation and write it in a rodboltlenght log sheet. So I can check if they are still good or not when I disassemble an engine later.
But here in this situation I think it is the safest way to advise the guy to replace them.
He is someone with no experience in building engines.

EnzoSpeed

Convince him to bite the bullet and replace them. I had to on my last build . I wasn't a fan of spending $100 on new bolts, but then again, I haven't spun a bearing yet either.

X-Mazda 3 Racer

Let him know that the material in the rod bolt os like paper. Once you over=stretch it, it rips and will never be able to yeild the proper clamping force ever again.

Also, ARP usually suggests only a 75% yeild on their bolts. This means that there is another 25% of torque that can be applied to the bolt before it reaches it's yeild point.

43 Ft lbs. is approx. 75%
Add the other 25% to yield the fastener ( aprox 10 ft lbs ) and you get 53 ft lbs. If he went to 59, then I would replace them.

Also, let him know that the rod big end was honed to size and shape at the proper TQ lever. Anything over or uner that level will distort bearing bore causing big problems later on down the road!

earl

If the guy is leaving the bolts at 59lbs, he will probably wind up spinning a rod bearing anyway.

hondaapi

Ok. I talked to him again.
I told him everything I know about engine building in this point. I learned it at Porsche for a couple of years and all my other projects in my own garage.

He donīt believe that because he canīt imagine. He also didnīt mesure the bearing clearances because he didnīt know what I was talking about.
So I decided to stop talking about that with him.
I believe it will be an expansive way for him to learn.
I can just hope it will not hit my reputation.

I let you know what happened ;-)

PrecisionH23a

He'll blame you. That's just how the game is.

I love it how people can fork over a few grand on a build and skimp out on something as simple as $70 bolts and blow their engine up.