I'm installing my rods and pistons back into the block, but im using ARP rod bolts.

Now, i've bought a rod bolt stretch gauge and im using this to torqe the ARPs down, the issue i'm having is with the amount of force im having to put on my spanner to get them to the .0075" of stretch. I'm haveing to turn it *really* hard, much harder than I thought I would.

Is this normal? i've only ever torqued bolts before and they seemed to require a lot less force than this.

 

I have no idea how hard, but they are ARP so it only makes sense to me that it would take a little more effort to stretch these bolts over OEM

 

What size bolts? For 5/16" bolts, the stretch spec is only .0055".

 

These are the bolts i'm using. The documentation that came with them suggested a stretch value of .0075 to .0079 I belive.

http://shopping.lightningmotor...age=1

 

If your using a half decent stretch gauge then trust it

 

Generally, you can torque the bolts to spec with a torque wrench, then add additional torque as necessary with the box wrench until you achieve proper stretch. It's usually a good bit of extra force past the torque spec because torque wrenches always read low due to excess friction between the non-ideal mating interfaces.

Also, you should have measured the length of each bolt before you torqued them at all. Make a sheet that shows the exact manufactured length of each bolt, down to .001". This should never change. If you ever fear that you've over-torqued a bolt, loosen the nut and measure the bolt - it should be back at the manufactured length. If the bolt is ever longer (even by 1 or 2 thousandths) then it's been stretched past yield and has plastically deformed.

I personally keep detailed charts for all my rod/head studs/bolts. If something ever comes up where I have to remove the head or rods, I check the lengths of everything to make sure nothing has stretched.