The HG thang

[SupBone]

Hi Guys, I've been reading and looking and redone this 7MGE thang (3) times now.
I saw the article that said the factory recall never happened; the new torque level should be 75 rather than 58.
Do i still need the Mtl Gas and the new Hd Bolts?
Orrr! do I retorque the existing and see if it holds first?
I can run up to 70 mph w/o pressure push back... w/ the AC on i can only do 60 before it will push air pressure out of the reservior.
I have a (3) row aluminium radiator on the way... i quess i'll be going in for round (4) but another TKO and I may throw in the towel!!
Somebody said that the HB sequence and torque has changed... i didn't get the memo...can somebody please hep me please, please hep me...

Sup Bone on the air... any 89 Targa's out there on the Gulf Coast!?!

 

[jenny89]

no do atlesast the 75 lbs and always replace the head bolts if you take them out, even if they were just put in

 

[jetjock]

^ That part about the head bolts is nonsense.

 

[jenny89]

tell that to a week old set of reused head bolts

 

[jenny89]

true it doesnt happen alot but after my experiences ill replace a set everytime

 

[Supracentral]

Neither the factory bolts, nor aftermarket ARP bolts/studs are torque to yield. Inspect them, if they are undamaged, reuse them. You'll note that in the TSRM they are not listed as single use, nor are there any specs for measured length or shoulder diameter, which are always provided for TTY bolts as they need to be checked for how much they have been stretched to see if they are reusable. Also, it's worth noting the aluminum head on the 7M wouldn't survive the level of torque you'd need to generate to get those bolts into the plastic range. It's a class 10.9 bolt if I remember correctly. They are elastic at all times in this application and you'd be hard pressed to "wear" a set out. You can look it up but I recall the yield strength for them being in the 900+ MPa range for those things. That's an insane amount of force.

 

[jetjock]

^ Yea, that too

 

[Backlash2032]

Neither the factory bolts, nor aftermarket ARP bolts/studs are torque to yield. Inspect them, if they are undamaged, reuse them. You'll note that in the TSRM they are not listed as single use, nor are there any specs for measured length or shoulder diameter, which are always provided for TTY bolts as they need to be checked for how much they have been stretched to see if they are reusable. Also, it's worth noting the aluminum head on the 7M wouldn't survive the level of torque you'd need to generate to get those bolts into the plastic range. It's a class 10.9 bolt if I remember correctly. They are elastic at all times in this application and you'd be hard pressed to "wear" a set out. You can look it up but I recall the yield strength for them being in the 900+ MPa range for those things. That's an insane amount of force.

So if the factory head bolts are plenty strong, and the head can't take that much force.. Why would somebody even consider buying ARP head bolts? Not studs. I know the advantage to studs. Is there any advantage to ARP bolts over factory bolts though?

 

[Supracentral]

Is there any advantage to ARP bolts over factory bolts though?

None in my opinion.

 

[Nick M]

So if the factory head bolts are plenty strong, and the head can't take that much force.. Why would somebody even consider buying ARP head bolts?

Because this site and SF is permeated with BS that can't get filtered or stomped fast enough.

 

[Jimbo]

And there I go getting suckered into buying used arp bolts.
Sunavabitch.

 

[jetjock]

Too much mechanic-ing and not enough basic engineering. Many (if not most) materials when kept within the elastic region have no fatigue limit. Not all though. Aluminum is one that comes to mind.

 

[jenny89]

learn somethin new everyday lol

 

[Jimbo]

So then it's koo if stock bolts are torqued past the usual 72lbs, up to ARP bolt spec?

 

[jetjock]

As long as they haven't been over-torqued before, yes. Btw I don't retorque. Never have on any of the engines I've built. Zero problems. I'm not surprised either.

 

[Turbo Habanero]

As long as they haven't been over-torqued before, yes. Btw I don't retorque. Never have on any of the engines I've built. Zero problems. I'm not surprised either.

JetJock do you not think a re-torque is needed with brand new Bolts/studs after a few heat cycles? When i re-torqued my studs to be 100% honest i did it at the 500 mile mark and they were originally put at 90ft lbs but man the torque specs where everywhere after 500miles, i waited another 500miles and checked again and they were spot on.

Not sure if you were just talking about stock bolts just sharing my experience.

 

[jetjock]

No, I don't. Do OEMs do it? Ever seen a shop make customers bring their cars back to do it?

 

[Turbo Habanero]

No, I don't. Do OEMs do it? Ever seen a shop make customers bring their cars back to do it?

I did think about this point also.

I don't know enough about it to disagree with your methods.
Just from what I've been taught to do in practice and the fact that I've seen the specs change personally made me want to ask you.

 

[jetjock]

You should do what makes you comfortable. I understand my view on this will be controversial but that how I feel. As long as the fasteners are installed correctly there should be no need for it and my experience has borne that out. Does ARP even say do it? Last time I checked they said to incrementally torque on installation which is what I've always done.

 

[Devin LeBlanc]

Never done a retorque on 30+ motors I've built, never had a problem. I think the issue with some is most of the time when the head studs or bolts loosen up over time after the re torque is due to the aluminum being annealed from previous over heat. Often over looked when putting back together.