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931 Head Installation Thread

 
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Sat Sep 04, 2021 6:00 am    Post subject: 931 Head Installation Thread Reply with quote

For the events leading up to this, see:

https://www.924board.org/viewtopic.php?t=44805&postdays=0&postorder=asc&start=0

So I have my head now and some spare parts as well. I've ordered most all of the gaskets, bolts, etc but I can't seem to find the exhaust manifold studs anywhere. Advice in the earlier thread was just to get something from the hardware store.

Can someone confirm the length of the exhaust manifold studs? I had written 25mm M8 w/ 1.25 pitch, but that 25mm can't be right...it's way shorter than what is currently in mine. I measure about 20mm worth of threads at each end and maybe 7-8mm of unthreaded space. None of them are free of either the head or manifold at this point though, so I may be off a bit, or I may have a non-stock part.

Is stainless preferable to grade 8 steel? Also someone in another thread mentioned copper nuts, is that correct?

Thanks...
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1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Tue Sep 07, 2021 1:19 am    Post subject: Reply with quote

Any reason I can't use 944 studs? They appear to be readily available and they're M8x46mm. Trying to measure mine in place I got 47mm so they have to be pretty similar? The two threaded halves may not be the same length, but has anyone used these?

My local recommended "bolt shop" said the only thing they have in M8 is 50mm. That definitely seems a bit too long, not sure if it's too long to matter but it might be, although I suppose they could be cut down.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Tue Sep 07, 2021 1:35 am    Post subject: Reply with quote

I found this thread but that certainly does not seem to match what's on my car:

http://924board.org/viewtopic.php?t=14514&sid=0b1a863b493bdef6e91a2db55f91fac7

It does however match the 25mm that I had previously read...
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Cedric  



Joined: 27 Aug 2004
Posts: 2204
Location: Sweden

PostPosted: Tue Sep 07, 2021 2:20 am    Post subject: Reply with quote

I can see if i can find my latest purchases. But I've ordered general VAG stuff both online and from the local vw shop before, both m8 studs and copper plated nuts, just be sure that they are suitable for exhaust components.
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Wed Sep 15, 2021 3:51 am    Post subject: Reply with quote

Does anyone know how long the threaded side of the stud that goes in the head is supposed to be? I bought some 40mm studs that are 10mm on one side and about 20mm on the other. The ones I took out are overall about 42mm but closer to symmetrical, so whichever side I screw into the head will be either longer or shorter than what came out. I want to avoid both too short to hold as well as long enough to do damage when being torqued down.

I still can't imagine how 25mm could be long enough...
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Sun Sep 19, 2021 12:48 am    Post subject: Reply with quote

Regarding manifold studs, the closest I could find locally are 10mm on the short side and 40mm overall. So, shorter on the head side, longer on the outside, but I checked and it seems to fit OK, so that's what I'm going with. Any thoughts on copper antiseize? I'm planning on using it on the studs, stop me if you disagree.

Planning on putting the MLS head gasket on dry...what about the pile of paper gaskets I have...do those go on dry? Or do you use some sort of sealant usually? Thinking distributor housing, intake manifold, tensioner/thermostat housing, etc etc....
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 369
Location: South Florida

PostPosted: Mon Sep 20, 2021 1:07 am    Post subject: Reply with quote

One other thing...the ARP head studs came with their own lubricant, which I'm using, but they mention "if any of the studs penetrate the water jacket, use ARP sealant." Now...I don't think any of ours do? Please correct me if I'm wrong....but I do seem to have oil in two of the stud holes. Is that normal?
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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View user's profile Send private message
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