Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

1980 MY Cylinder head bolt torque question?

 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech.
View previous topic :: View next topic  
Author Message
Svobodin  



Joined: 08 Oct 2013
Posts: 67
Location: Colorado

PostPosted: Tue Sep 24, 2019 12:20 am    Post subject: 1980 MY Cylinder head bolt torque question? Reply with quote

The factory service manual technical update bulletin for 1980 says that for all cylinder head bolts 1980 MY and up (polygon aka triple square) need to be torqued to 65Nm, then warm up the engine and torque an extra 180 degrees, and retorque after 1000 miles

However, I have hex head cylinder head bolts on my 1980 931.
The torque spec according to the FSM for hex head bolts is 120Nm, and retorque after 1000 miles. Should I follow the hex or the triple square torque spec?

Also, are the Hex head bolts stretch bolts?
I've been told by a good mechanic friend with decades of VW/Audi/Porsche experience that they can be reused, while my other mechanic friend also with decades of Porsche/BMW/Mercedes experience is telling me not to reuse them....
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK

PostPosted: Tue Sep 24, 2019 8:31 am    Post subject: Reply with quote

There’s a later bulletin for torquing......
Cannot remember which, Hex or 12 point, but one is stretch and one isn’t if OEM Porsche. Non stretch can be reused but stretch bolts cannot.
Or go for Sierra/Escort Cosworth ARP studs, better clamping on a turbo
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Svobodin  



Joined: 08 Oct 2013
Posts: 67
Location: Colorado

PostPosted: Fri Oct 04, 2019 3:32 am    Post subject: Reply with quote

Carrera RSR wrote:
There’s a later bulletin for torquing......
Cannot remember which, Hex or 12 point, but one is stretch and one isn’t if OEM Porsche. Non stretch can be reused but stretch bolts cannot.
Or go for Sierra/Escort Cosworth ARP studs, better clamping on a turbo


I do have the technical update, but it does not specify whether they are stretch bolts or not. These are Porsche OEM hex-head studs and are original to the car.

Anyone have any sources? I will be working on the car this weekend hoping to get it running.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech. All times are GMT + 10 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group