Question on torquing ARP head studs

Novak

Novak

SQUIRREL TRYN TO GET A NUT
Jun 15, 2015
990
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Cloud 9, IDAHO
On this note I have a question. We have a technician that assisted in building "The Barn Stormer" & "The Raging Bull" which are both 1700+ hp tractor sled pullers and he claims that you don't torque to yield and that you tightened them down snug and then torque them 3x instead of doing them gradually from
40ftlbs to 60ftlbs and so on like the ARP guide says to.
How did you guys do them?



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Burn Down

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
Novak said:
On this note I have a question. We have a technician that assisted in building "The Barn Stormer" & "The Raging Bull" which are both 1700+ hp tractor sled pullers and he claims that you don't torque to yield and that you tightened them down snug and then torque them 3x instead of doing them gradually from
40ftlbs to 60ftlbs and so on like the ARP guide says to.
How did you guys do them?



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Not sure? I used the ARP instructions, after all they designed the fastener:D Torque to Yield hardware is pretty much one time use stuff. I know they can be reused in a pinch but the integrity of the fastener could be compromised and fail.
 
Novak

Novak

SQUIRREL TRYN TO GET A NUT
Jun 15, 2015
990
0
16
Cloud 9, IDAHO
Burn Down said:
Not sure? I used the ARP instructions, after all they designed the fastener:D Torque to Yield hardware is pretty much one time use stuff. I know they can be reused in a pinch but the integrity of the fastener could be compromised and fail.
Click to expand...



Same here, when we did the LLY i remember you touch each stud 9X by the time you finish. Granted it's been over 2 years sooo I could be wrong on that digit


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PureHybrid

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,495
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Central OH
Novak said:
Same here, when we did the LLY i remember you touch each stud 9X by the time you finish. Granted it's been over 2 years sooo I could be wrong on that digit


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I believe a while ago, ARP had you increase torque in 3 steps, then back off each stud one at a time and retorque (like a burnishing procedure). Might be where you got that from. I think the procedure changed when they came out with the ARP super lube.
 
Burn Down

Burn Down

Hotrodder
Sep 14, 2008
7,092
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48
Boise Idaho
Novak said:
And to stretch studs?


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The final torque is the stretch on the stud. The main studs on Some Caterpillar engines are stretched with a hydraulic ram to a specified amount and then you just run the nut up to the main cap and let the ram off. Small fasteners are easier to torque because there is less drag on the flanges of the nut and bolt head. Larger fasteners that are critical usually are torque turned with a specific lubricant. They can be accurately torqued to a small number then turned 90* 0r 120* etc. etc. the manufacturer has figured out the amount of stretch needed. Clear as Mud?:D
 
PureHybrid

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,495
476
83
Central OH
Burn Down said:
The final torque is the stretch on the stud. The main studs on Some Caterpillar engines are stretched with a hydraulic ram to a specified amount and then you just run the nut up to the main cap and let the ram off. Small fasteners are easier to torque because there is less drag on the flanges of the nut and bolt head. Larger fasteners that are critical usually are torque turned with a specific lubricant. They can be accurately torqued to a small number then turned 90* 0r 120* etc. etc. the manufacturer has figured out the amount of stretch needed. Clear as Mud?:D
Click to expand...

Sounds interesting. We have a similar procedure with our compressor piston rods. What kind of pressure do they run on that tool?
 
Novak

Novak

SQUIRREL TRYN TO GET A NUT
Jun 15, 2015
990
0
16
Cloud 9, IDAHO
Burn Down said:
The final torque is the stretch on the stud. The main studs on Some Caterpillar engines are stretched with a hydraulic ram to a specified amount and then you just run the nut up to the main cap and let the ram off. Small fasteners are easier to torque because there is less drag on the flanges of the nut and bolt head. Larger fasteners that are critical usually are torque turned with a specific lubricant. They can be accurately torqued to a small number then turned 90* 0r 120* etc. etc. the manufacturer has figured out the amount of stretch needed. Clear as Mud?:D
Click to expand...


That actually does make sense. Our CASE's have a system like that.


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Novak

Novak

SQUIRREL TRYN TO GET A NUT
Jun 15, 2015
990
0
16
Cloud 9, IDAHO
PureHybrid said:
I believe a while ago, ARP had you increase torque in 3 steps, then back off each stud one at a time and retorque (like a burnishing procedure). Might be where you got that from. I think the procedure changed when they came out with the ARP super lube.
Click to expand...



Yea you would torque them and then back them out and finger tighten them back down and do it all over again to the next torque range. We were there doing that for hours it seemed like. But 2 years on a hot tune and she hasn't pushed water. BTW the harbor freight hood creeper was the best Chinese tool ever made for this process


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WolfLMM

WolfLMM

Making Chips
Nov 21, 2006
4,005
26
48
38
AL
Burn Down said:
The final torque is the stretch on the stud. The main studs on Some Caterpillar engines are stretched with a hydraulic ram to a specified amount and then you just run the nut up to the main cap and let the ram off. Small fasteners are easier to torque because there is less drag on the flanges of the nut and bolt head. Larger fasteners that are critical usually are torque turned with a specific lubricant. They can be accurately torqued to a small number then turned 90* 0r 120* etc. etc. the manufacturer has figured out the amount of stretch needed. Clear as Mud?:D
Click to expand...

That's cool Albert. I've seen our cat guys use a mobile hydrualic ram to tighten the nut that holds piston on larger hydrualic rams. I talked to the guy doing it and the tq spec was like 4500 ft/lbs. so he just watched the psi gauge on the tighten ram till it hit 4500psi and the nut was tightened to spec. Took it like 20minutes to tq that bad boy lol.
 
Burn Down

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
WolfLLY said:
That's cool Albert. I've seen our cat guys use a mobile hydrualic ram to tighten the nut that holds piston on larger hydrualic rams. I talked to the guy doing it and the tq spec was like 4500 ft/lbs. so he just watched the psi gauge on the tighten ram till it hit 4500psi and the nut was tightened to spec. Took it like 20minutes to tq that bad boy lol.
Click to expand...

He was using a Hyd. tq wrench they are super sweet:thumb:
 
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