Cylinder head bolts
03-23-2009, 08:52 PM
#1
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Cylinder head bolts
Could someone please tell me the size of the cylinder head bolts? There are 12 of them and they look like torx bolts, but have 12 points instead of 6 points (internal, 12 point socket). I think they also might be called triple square? These are the bolts that are revealed after the valve cover is removed (cams exposed). Any help would be appreciated.
Dave
Dave
03-23-2009, 09:09 PM
#2
The PN is 034 103 385 C
and they are common to the 20v 7A and the 20vT 3B, AAN, ABY and ADU engines.
Probably the same as a 2.0L 16V VW engine head bolts (027 103 385C) (but don't quote me).
They are single use stretch bolts (they yield during the torquing sequence and cannot be re-used).
Alternative is ARP head studs which do NOT yield and can be reused.
Look on page 40 of this ARP catalogue pdf:
http://video.arp-bolts.com/catalog/ARPCatalog.pdf
Probably the same as a 2.0L 16V VW engine head bolts (027 103 385C) (but don't quote me).
They are single use stretch bolts (they yield during the torquing sequence and cannot be re-used).
Alternative is ARP head studs which do NOT yield and can be reused.
Look on page 40 of this ARP catalogue pdf:
http://video.arp-bolts.com/catalog/ARPCatalog.pdf
Last edited by UrS4boy; 03-23-2009 at 09:17 PM.
03-23-2009, 09:30 PM
#5
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M12 triple square try to get reinz or oem head bolts not meyle!!! But by that time you're almost half the cost of ARP head studs so....... any how you can get the ARP studs at summitracing
http://store.summitracing.com/partde...4&autoview=sku
http://store.summitracing.com/partde...4&autoview=sku
Last edited by yodasfro; 03-23-2009 at 10:58 PM.
03-24-2009, 05:07 AM
#6
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M12 triple square try to get reinz or oem head bolts not meyle!!! But by that time you're almost half the cost of ARP head studs so....... any how you can get the ARP studs at summitracing
http://store.summitracing.com/partde...4&autoview=sku
http://store.summitracing.com/partde...4&autoview=sku
03-24-2009, 05:46 AM
#7
Yes you are missing something. The picuture in the link is the ARP head studs that I
was suggesting in my post as well. The suggestion is the ARP head stud kit is not that much more than the stock head bolts, at least when you consider that the ARP studs are reusable whereas the OE head bolts are not.
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03-24-2009, 11:17 AM
#9
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You don't want the undercut headstuds, as was posted previously. These are designed with a substantial amount more 'give' in them for motors with large amounts of thermal expansion.
The straight cut head stud kit is the standard kit you'll want to look for. We've run them over 800whp without any problems. Kit pays for itself if you ever need to pull the head again.
20v Head Stud Kit
The straight cut head stud kit is the standard kit you'll want to look for. We've run them over 800whp without any problems. Kit pays for itself if you ever need to pull the head again.
20v Head Stud Kit