Posted By: RapidRobert
LA block/mag head bolt torque Q - 08/17/14 07:29 PM
MP torque to yield (I believe) head bolts with the integral "washer" built into the bolt head. Found several sites that said step one go to 50 then step 2 go to 105. I am getting ready to go together TODAY and I'm wondering why they are sayin 2 steps when at least 3 (if not more) is the norm. unless it is something to do with the TTY type or am I just overthinking. I will go to 105 in many steps unless you guys advise otherwise. thank you for your time. EDIT I just went to 105 in 6 steps
Posted By: denfireguy
Re: LA block/mag head bolt torque Q - 08/18/14 03:06 PM
You should be okay. I did ARPs in 6 steps without a problem...at least so far.
Posted By: RapidRobert
Re: LA block/mag head bolt torque Q - 08/18/14 03:12 PM
Yeah I just didn't grasp the "torque to yield" part
& I was sweatin a bit when I was comin up to 105
Posted By: dogdays
Re: LA block/mag head bolt torque Q - 08/18/14 05:10 PM
That's right, they are NOT torque-to-yield.
You can torque them in two steps or I usually do three.
A torque-to-yield bolt usually tightens to a certain torque and then you turn the bolt so many degrees.
When I was torquing the head bolts on my 318, I found at least two different torque values for LA motors.
R.
I've been thinking about this. It always takes more torque to start the bolt moving than it takes to keep it moving. A more technical way of saying this is that the static coefficient of friction is greater than the moving coefficient of friction. SO, if you take too many baby steps, the last step you may hit the required torque value just trying to start the bolt. Unfortunately the bolt won't really be torqued correctly, but it will appear so. So you need to start far enough back that your starting torque is comfortably lower than your target torque.
This is more easily seen with a dial indicator type torque wrench.