Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 944 Turbo and Turbo S

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Nov 2010
Posts: 108
Question Cylinder Head Torque

Greetings,

I am in the process of replacing the head gasket on my 1987 951 and I am not sure how to torque the nuts. The Porsche Workshop Manual (see image below) for the turbo specifies specific torque values but the procedures at Clark's and Rennist both specify turning angles. Which is correct? Is there perhaps a service bulletin or something covering this that I didn't manage to find? Or different for different years maybe?

Thanks!


Last edited by notMyScreenName; 04-22-2014 at 07:01 PM..
Old 04-22-2014, 06:24 PM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Jan 2013
Posts: 7
Hi!

I just went through this adventure myself last fall. I never did check the service manual, I just followed the excellent HG replacement procedure found here: 1986 Porsche 951 Head Gasket Procedure

There are two types of head studs: Torque to yield (TTY)(the ones with turning angles) and ones that just have a torque value.

My understanding is that the 951 has the TTY type. These head studs stretch when tightened down and ideally should be replaced each time the head is removed. Lots of guys don't, though. In fact my local 944 specialty shop doesn't unless they feel one really stretch out when tightening the head down.

So - I am as confused as you are about why the service manual does not specify turn angles, so I can't help you there. I can tell you that I did not replace my head studs and I followed the turn angle procedure and my car is running fine. YMMV.
Old 04-23-2014, 05:59 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Shade Tree Mechanic
 
David Floyd's Avatar
 
Join Date: Jan 2002
Location: Tennessee
Posts: 12
Torque values have always worked for me
__________________
87 951 106mm 2.785 ltr
Old 04-23-2014, 08:03 PM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Jan 2013
Posts: 7
Also - a word of warning - learn from my mistake!

I replaced the HG and belts last fall late in the season right as first snow was happening. I was very happy that the car started up and ran but didn't have a pressure tester to properly fill the cooling system, so I just parked it for the winter.

Fast forward to this spring. The first time I revved it up giant white clouds came out the tailpipe and it wouldn't idle. I thought for sure that I blew another HG for some reason and had it towed to the shop.

It turns out that during the original HG failure, coolant was pushed up past the intake valves and flowed down and pooled in the intercooler. When I revved it after replacing the HG, this coolant in the intercooler was forced up into the intake by the turbo. This resulted in the symptoms I was seeing.

So - if your HG blew, be sure to drain your intercooler!
Old 04-24-2014, 09:54 PM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Nov 2010
Posts: 108
Thanks for the replies. I really appreciate it.

I just now managed to get back to this project and just got the head back from the machine shop so I'll be putting it all back together as soon as the new nuts/washers get here (I'm keeping the existing studs). Anyway... Looking further through the factory manual I came across the page pictured below, so I am assuming that the turning-angle method of torquing the bolts supersedes the torque-value method. So I guess I'll be doing it that way. For those who've done it - so I know what to expect: How hard a pull is the last 90-degrees? Does it feel like it's in the 90Nm range or is it harder?

Thanks again, and any other tips or suggestions are more than welcome.

Old 04-28-2014, 07:55 PM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Eric
 
Join Date: Apr 2009
Location: Brisbane, Australia
Posts: 270
Garage
My recollection is that it felt a little tighter than 90nm.
__________________
Eric
Old 05-10-2014, 02:50 AM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
Join Date: Feb 2003
Location: East Bay
Posts: 1,451
It's about 10% tighter than the earlier 90nm spec.

Similar issue with the MKIII Supra Turbo as well, torque was too low and leaking/blowing headgaskets. Tech-bulletin update called for 10% higher torque there as well.
Old 05-19-2014, 02:44 PM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 

Tags
944 turbo , 951 , cylinder head , torque


All times are GMT -8. The time now is 01:10 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2017 Pelican Parts LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.