Removal of head bolts
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Mudding
Joined: Aug 2014
Posts: 198
Likes: 10
Using ARP head bolts for some years on the Vauxhall Caterham, Ford BDA and Pajero heads. The Paj suffers the same issues as the D2 V8 with blown head gaskets albeit an alloy head to iron block but much higher compression ratio, 19.5:1. I would have thought that 'first use' threads could take much more than 90 lb/ft but problem is stretched weakened threads in well used blocks create a different scenario and also embrittlement comes into play. If it were me, I'd go for 3-4 torquing stages on an older block with the thread super lube and after 3 button it up and run the engine up to temp and then a final re-tighten to say 90 lb/ft once cooled down. Alternatively, as Dusty states, let the bolts stretch some overnight and do a final tighten which saves refitting all the rocker covers and intake tat and then stripping it all off again then refitting it all back - tedious or what?
I hate head bolt threaded into alu blocks in any case 'cos they always frick up sooner or later
Source some helicoils or inserts just in case.
I hate head bolt threaded into alu blocks in any case 'cos they always frick up sooner or later
Source some helicoils or inserts just in case.
OK, guys...I appreciate the guidance, but let's clarify:
I'm using the ARP stud/nut kit, NOT bolts. The reason I'm going to the studs is for just the reason Dusty stated - I don't want to pull the freakin' threads out of the block!
And I have no intention of pulling the upper intake and valve covers again once it's buttoned up to re-torque after heat cycle. That's WHY I'm going away from the factory stretch bolts!
Is 100 ft.lb. excessive with the stud/nut kit, or should I settle for the 88-90 range?
Super Moderator
Joined: Jul 2013
Posts: 5,794
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From: dallas texas
That is the question.... Most get to 80 and call it good. Arp has had that 100 info up for years. I've only used the studs once. 100 seems excessive and a risk.
Maybe start a new thread to get more opinions.
Maybe start a new thread to get more opinions.
Baja
Joined: Aug 2013
Posts: 5,845
Likes: 368
From: Near Bordeaux, France
OK, guys...I appreciate the guidance, but let's clarify:
I'm using the ARP stud/nut kit, NOT bolts. The reason I'm going to the studs is for just the reason Dusty stated - I don't want to pull the freakin' threads out of the block!
And I have no intention of pulling the upper intake and valve covers again once it's buttoned up to re-torque after heat cycle. That's WHY I'm going away from the factory stretch bolts!
Is 100 ft.lb. excessive with the stud/nut kit, or should I settle for the 88-90 range?
I'm using the ARP stud/nut kit, NOT bolts. The reason I'm going to the studs is for just the reason Dusty stated - I don't want to pull the freakin' threads out of the block!
And I have no intention of pulling the upper intake and valve covers again once it's buttoned up to re-torque after heat cycle. That's WHY I'm going away from the factory stretch bolts!
Is 100 ft.lb. excessive with the stud/nut kit, or should I settle for the 88-90 range?
Pro Wrench
Joined: Jan 2011
Posts: 1,869
Likes: 44
From: Philly
I stopped twerking my stud nuts at 70ft/lbs.
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Mudding
Joined: Aug 2014
Posts: 198
Likes: 10
I believe I do agree. 100 ft.lb. seems a bit extreme. After reading the "ARP Studs vs. Stretch Bolts" thread from 1 1/2 yrs. ago, I think I'll stick to the 25-50-75 ft.lb. technique.
Last edited by sdhow; Dec 30, 2014 at 12:56 PM.
Super Moderator
Joined: Jul 2013
Posts: 5,794
Likes: 211
From: dallas texas
that is a safe #.
some get away with 60. some say 80 is the #. ^ coors went 70.. I would have stopped at 80, but decided to let them sit overnight and hit them with 8 more the next morning (still felt like I was doing a root canal) I have an arp set on my bench, building a new engine. when my heads arrive, I will be stopping at 80. actually I my plan of attack is 20..40.....60..................................... .................80
I think 70-80 is the best/safest clamping zone
some get away with 60. some say 80 is the #. ^ coors went 70.. I would have stopped at 80, but decided to let them sit overnight and hit them with 8 more the next morning (still felt like I was doing a root canal) I have an arp set on my bench, building a new engine. when my heads arrive, I will be stopping at 80. actually I my plan of attack is 20..40.....60..................................... .................80
I think 70-80 is the best/safest clamping zone
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Mudding
Joined: Aug 2014
Posts: 198
Likes: 10
Thanks, Dusty!
Got the bolts out; nearly broke my thumb when one FINALLY let go and smashed my thumb between the cheater pipe and the radiator support! The factory must have these torqued in there at an ungodly high value...or used no anti-seize. Torqued the nuts at 25-50-75...then came back and hit them at 88 ft. lb.
This seemed to work fine.
Got the bolts out; nearly broke my thumb when one FINALLY let go and smashed my thumb between the cheater pipe and the radiator support! The factory must have these torqued in there at an ungodly high value...or used no anti-seize. Torqued the nuts at 25-50-75...then came back and hit them at 88 ft. lb.
This seemed to work fine.