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Discussion and questions related to the course Practical Engine Building
hello, I am having an issue with ARP Mainstuds as I torque them to ARP specifications. Using the 3 step torque procedure (15-30-60 ft-lbs), around 30 ft-lbs. 2 of the studs started to spin a quarter of a turn before it tightened back and reached the torque spec. (they were hand tight, as per ARP instructions)
I used a straight edge to check the height of the studs and they all look even. I also made sure to clean the threads using a thread chaser without a tapered bottom to ensure I get the whole thread.
My question is, is this safe to proceed with? or do i have another issue?
The engine is a 05 Evo 4g63 block. I am in the process of blue printing. Thank you!
Hello Mario yes this is not an issue at all, you can relax and carry on
"Hand tight" is going to mean different things for different people - I have strong hands and wrists and could apply considerably more torque than some others, even with the same interpretation. IMO, it would be much better if they specified, say, 15 lbs.ft.
What I suspect is there was slightly more resistance to 'hand tightening' in those two instances. Not really something to worry about, but if in doubt you could back the nuts off and use an Allan key to make sure the studs are fully bottomed out, before re-torquing the nuts.
Thanks. You guys are awesome!
I've seen this across various applications before and if I was only 'hand tightening' the studs in I would use a low strength loctite and mark the studs with a line to easily identify if they move, the heights would also be measured to make sure they are all even. (Loctite allowed to set of course)
I would personally apply a small torque, like Gord says, 15Nm let's say so that I would know they where seated at the bottom of the hole.
It's not a big drama; but it's something that can cause some blocks to crack if the stud is wound too much into the block (this used to be a common problem in early toca btcc engines)
Hydraulic splitting of the block's been known to happen when people have used too much oil or grease to lubricate blind bolt holes.