Re: ARP Bolt and Stud Stretch Specs
[Re: earlymopar]
#2940310
07/05/21 10:21 PM
07/05/21 10:21 PM
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Joined: Aug 2003
Posts: 43,274 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,274
Bend,OR USA
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I've used a bunch of he ARP main studs on both BB and SB Mopars, never seen mention of a stretch length for them in the instruction sheets Finger tight installed into the blocks and the torque reading in Ft. Lbs. with their moly is all I remember reading on the instruction sheets now. I do have several of those sheets saved out in my shop so maybe, if I can remember, I'll dig one out and copy it and attach it to this post tomorrow
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: ARP Bolt and Stud Stretch Specs
[Re: Cab_Burge]
#2940317
07/05/21 10:55 PM
07/05/21 10:55 PM
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Joined: Aug 2019
Posts: 9,546 Super Spudsville
Mr PotatoHead
Half Baked
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Half Baked
Joined: Aug 2019
Posts: 9,546
Super Spudsville
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Been a few too many years 4? to recall but the last set of arp rod bolts I put into oem type rods were either tq or stretch and came with an instruction sheet with specs n stretch. If your trying to stretch your rod bolts I think you can find it in this link with your pn. I pre stretched mine twice then set the third time, not sure if it was needed but its still running. https://arp-bolts.com/p/instructions.php
STOP POTATO HATE!
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Re: ARP Bolt and Stud Stretch Specs
[Re: Cab_Burge]
#2940417
07/06/21 09:03 AM
07/06/21 09:03 AM
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Joined: Feb 2003
Posts: 912 London, England
mopar_mark
super stock
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super stock
Joined: Feb 2003
Posts: 912
London, England
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I've used a bunch of he ARP main studs on both BB and SB Mopars, never seen mention of a stretch length for them in the instruction sheets Finger tight installed into the blocks and the torque reading in Ft. Lbs. with their moly is all I remember reading on the instruction sheets now. I’ve also never seen info on checking stretch on main studs. I’m not even sure how you would be able to measure.
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Re: ARP Bolt and Stud Stretch Specs
[Re: mopar_mark]
#2940425
07/06/21 09:21 AM
07/06/21 09:21 AM
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Joined: Jan 2003
Posts: 10,015 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,015
Frostbitefalls MN (Rocky&Bullw...
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For studs, the surface of the washer facing the block needs to ve scuffed with 500 grit sandpaper so it grips the cap or head surface. Just lightly scuffed so the washer can' t be turned by the nut. According to ARP 85 percent of torque goes to overcome friction, so using plenty of lube is vital in getting the right load on the studs or bolts.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: ARP Bolt and Stud Stretch Specs
[Re: earlymopar]
#2940756
07/07/21 09:28 AM
07/07/21 09:28 AM
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Joined: Jan 2003
Posts: 1,763 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,763
Windsor, ON, Canada
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...I can't see why you couldn't simply measure off of the end of the stud for stretch (after the thread clearance had been taken up between the block female threads and the male threads on the stud). However, ARPs reply back to me this morning indicates using the torque value is what they suggest. Hmm, my thinking was a bit different. Given the amount of stretch you'd expect to see I think it would be hard to consistently locate the stud well enough in the block to always take up the extra "wiggle room", and therefore give you a stable baseline measuring and starting point. After all, they normally say "put the studs in finger tight", and when the total stretch may only be 0.025" (guess only, but I'm comparing to a rod bolt that's typically in the 0.006-0.007 range) there is just too much room for an error to creep in when simply installing the studs. So instead of the above I was thinking of using the OAL of the stud as an indicator to see if the stud was over-stretched, along the lines of the rod bolt check you'd normally do. For that to work you'd need some kind of a range from ARP that says: if the bolt OAL increases beyond this point that means it's lost it's ability to retain torque. If that info was available you'd be able to torque it down to the advertised torque (110 ft-lbs in my case), and periodically (during refresh perhaps) pull the studs to re-measure the OAL to see if they were stretched past their initial length and therefore are suspect and should be replaced.
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