MichaelDelaney on Mar/27/05 said:ARP 2000 Pro-Series Wave-Loc
Bolt Stretch 5/16 in. (8mm) 208-6001 0.0048-0.0052 in.$45
Bolt Stretch 3/8 in.(9mm) 208-6401 0.0075-0.0079 in. $95
Quote: pdf file catalogue, p.29, ARP part # 208-6401, 9 mm ARP 2000 ProSeries Wave-Loc
1.) lube threads and nut flange face w/ provided ARP assy lube
2.) Recommended rod bolt stretch = .0075" - .0079" [preferred method]
Otherwise, torque to 40lb*ft (final). There should be a step-torque in there to like 20lb*ft first, then 40lb*ft. Loosen and re-torque. Do this a total of 3x to get sufficient rod bolt stretch.
Fasteners oNLY hold properly when they have been stretched a specific amount (depending upon material and size). Basically, as you tighten the fastener you remove the elasticity of the fastener.
It may seem counter-intuitive, but "strong" fasteners will still be quite elastic at tensions (or "torques" as read on a torque wrench) that are ideal for weaker fasteners.
The bolt needs tension, not torsion, to take up it's elasticity. Which measurement relates directly to tension??? If you have a burr on a thread, the torque reading will not be accurate.
If you change lubricants on the threads, you will get different stretch values at the same torque. The oNLY way to know that you have properly obtained the needed amount of bolt tension on a rod bolt, is via stretch measurement.
The elasticity of the bolt will become VERY obvious when you use the stretch gauge. The first 50% of the stretch is amazingly easy to take out. The effort past that increases exponentially. The last 5% of the stretch will take a tremendously greater effort than what you will probably expect.
And remember that every time you stretch (tighten) a fastener, it work hardens, so the stretch and torque values will change.