straightlinespeed
Sometimes I pretend to be normal
Very interesting read! Thanks for all the knowledge everyone.
Crank bore refinished? Wouldn't I have already had that issue when they were re-sized already? Because everything got pretty good.
From ARP catalog:
Are ARP bolts and studs re-usable?Yes. As long as the fasteners have been installed and torqued correctly, and show no visible signs of damage, they can be re-used. If they show any signs of thread galling or corrosion, they should be replaced. In the case of rod bolts, if any of them have taken a permanent set and have stretched by .001 or longer, you should replace them immediately. See page 29 in the catalog for more detailed information on this critical measurement.
Here's page 29:
http://arpcatalog.com/?src=home#29/z
Also, minute differences in the rod bolts diameters will place the rod caps in an ever so slightly different place than the old rod bolts. When you're talking about thousandths of an inch clearances, the least little change can be a big one.
I don't totally agree with their write up.
They recommend throwing away a bolt that has a .001" of permanent stretch. EVERY BOLT GETS .001" OF STRETCH WHEN TORQUED PROPERLY...
I don't totally agree with their write up.
They recommend throwing away a bolt that has a .001" of permanent stretch. EVERY BOLT GETS .001" OF STRETCH WHEN TORQUED PROPERLY.
Their way of measuring bolt stretch is not accurate. They say to use a "bolt stretch" gauge when you tighten the bolt/nut. this method also gives elastic and plastic deformation. Elastic deformation will go back when the load is taken off. Plastic deformation is permanent stretch and can only be measured when the bolt is not tightened, before you tighten it, and then after it has been loosened. You can't determine the amount of plastic deformation by measuring the bolt length under load.
When I did my bolt stretch studies, I brought the rod bolts to the tool room to be ground and centered. This is where they GRIND the ends flat and parallel and drill center holes exactly in the center of the head and tip of the bolt. Then I would etch numbers in the bolts and measure them with ball micrometers. You have to use ball mic's as calipers are not accurate enough - ask M. Koppesser (he didn't listen to me and had to do his test over).
Then take them to the rod machining line and get them loaded in some rods and follow them to the end of the line. After they are finished, then I would loosen the nuts and re-measure the bolt length with ball micrometers (ball mic's). This will give you the accurate permanent deformation.
I would then have pistons pinned to the rods and then install the pistons in engines and send them through the dedicated torque multiples and record the data from the multiple for torque and angle. Then remove the pistons from the engine, and measure the bolts again with ball mic's.
I have done bolt stretch test, and worked with the industry experts to set up the equipment needed to torque the rod bolts properly. I am not just some "internet jockey" throwing bull ****.....
Yes. The rods need to be resized when the rod bolts are replaced. I have seen some disagree, but IMO it is imperative. Think of all that's at stake. Nuff said.
May as well just buy some new Scat I Beams. You will be $ and miles ahead of the game.
I must be the luckiest person on the planet! Back in the "bad old days" we street raced and ran the hell out of mud trucks with "dirt road rebuilds" all the time. These were our daily drivers as well! My friends and I had piles of core engines and would rob a rod out of one if we needed to replace one that spun a bearing. One 360 (I called it lucky) that I ran in a nearly 4000lb. W100 had three #7 rods in it. My 72 challenger had a 340 that I built out of a pile of cores I bought off a retired bracket racer. That motor saw 8000 rpm on a regular basis at the hands of a rowdy 17 year old. The only thing we took a motor to the machine shop for was to get a block boiled.
Well that would be if I do go with new rod bolts, but these ones if I don't replace them are ready to go back in. I guess ive just gotta decide, arp and my engine guy say they are fine, while you guys say to replace em lol. No replacing them is alot easier on the wallet anyways.
Exactly. Much like I described the action of the rod bolts stretching with every RPM cycle. It does not matter whose rod bolt you use. They all have a shelf life.
What gets me is, how many people do an old dirt road build and actually get by re-using rod bolts with 100K plus miles on them. I would do that and sling a rod into next week.
I don't totally agree with their write up.
They recommend throwing away a bolt that has a .001" of permanent stretch. EVERY BOLT GETS .001" OF STRETCH WHEN TORQUED PROPERLY.
Their way of measuring bolt stretch is not accurate. They say to use a "bolt stretch" gauge when you tighten the bolt/nut. this method also gives elastic and plastic deformation. Elastic deformation will go back when the load is taken off. Plastic deformation is permanent stretch and can only be measured when the bolt is not tightened, before you tighten it, and then after it has been loosened. You can't determine the amount of plastic deformation by measuring the bolt length under load. ...
I don't see anywhere I have made a recommendation for your case either way. I will tell you this. If I were in your place, I would use the rod bolts again so quick, I wouldn't have time to think about it. How's that for a recommendation? lol
I'd have to agree. SBM rods are pretty beefy, have taken a set, and have had the big ends redone with quality rod bolts, then run for 3,000 miles. Just don't blame RRR or I if a rod scatters causing an expensive mess...
I'd have to agree. SBM rods are pretty beefy, have taken a set, and have had the big ends redone with quality rod bolts, then run for 3,000 miles. Just don't blame RRR or I if a rod scatters causing an expensive mess...
i certainly cannot disagree with that logic.
It wouldn't be a total loss.....scrap iron is selling for $200 a ton here.......
So the plastic deformation is what the concern would be, so if there is a measurable amount the bolts are no good from what I am understanding?
I don't see anywhere I have made a recommendation for your case either way. I will tell you this. If I were in your place, I would use the rod bolts again so quick, I wouldn't have time to think about it. How's that for a recommendation? lol
yes, when you tighten a bolt, you get both plastic and elastic deformation.
Elastic deformation is stretching that goes back when the load is released. (Like a spring, it goes back when unloaded).
Plastic deformation is when the bolt stretches PERMANENTLY and does not go back when unloaded.
You cannot measure plastic deformation with the bolt under clamp load.
It is difficult to get an accurate reading for bolt length unless the bolts are ground flat/parallel and with centers drilled in them. Otherwise the ridges that are made when they form the bolt can throw off the measurements.
Try to measure a bolt 10 times and see if you get the same exact reading every time. If you can't, then your measurement method is not good enough....
You have to use micrometers, not calipers. Calipers are not sensitive enough...