Interest THE strongest possible headstuds?
02-02-2017, 07:17 AM
#1
Nordschleife Master
Thread Starter
Interest THE strongest possible headstuds?
The main problem of getting high hp reliable from these engines is cylinder head sealing. Head lift is IMHO the main problem that keeps us back.
As some of you know I've been working a lot on these engines and my current engine concept with a 3.1l 16v turbo 770 hp engine has been tortured in Timeattack racing for several seasons now.
I've made a new head gasket design available through Athena to help with the engine sealing. My engine also have large 9/16 ARP head studs to help clamping force. But I've now reached a limit where I still have sealing issues over the course of a season even with the special gasket and large studs.
This have led me to look into the best possible head stud setup. In contact with ARP I have received a quote for 9/16 head studs in their very strongest material - Custom Age 625+.
However, it is very expensive. If I commission them to manufacture 3 complete sets with studs, washers and nuts it will cost 1029 USD per set. I'm looking to have more sets made and I could potentially offer complete sets for around 900 USD.
Might seem like a lot of money for studs compared to the regular ones but considering what needs to be spent to make a reliable high hp 3.0l 16v engine this is IMHO a given investment and potentially what will allow us to get into the 900 hp range without sealing issues.
Info about the material:
Custom Age 625 Plus®: This newly formulated super-alloy demonstrates superior fatigue cycle life, tensile strength and toughness – with complete resistance to atmospheric corrosion and oxidation. ARP is the first to develop manufacturing and testing processes for fasteners with Custom Age 625+. Best of all it is less expensive and expected to soon replace MP-35 as the material of choice in the high strength, super-alloy field. Typical tensile strength is 260,000-280,000 psi.
These studs have raised the bar for other engine types.
These will be made for 3.0l 16v and are in 9/16 which means you will have to tap the block to fit these.
Any interest?
As some of you know I've been working a lot on these engines and my current engine concept with a 3.1l 16v turbo 770 hp engine has been tortured in Timeattack racing for several seasons now.
I've made a new head gasket design available through Athena to help with the engine sealing. My engine also have large 9/16 ARP head studs to help clamping force. But I've now reached a limit where I still have sealing issues over the course of a season even with the special gasket and large studs.
This have led me to look into the best possible head stud setup. In contact with ARP I have received a quote for 9/16 head studs in their very strongest material - Custom Age 625+.
However, it is very expensive. If I commission them to manufacture 3 complete sets with studs, washers and nuts it will cost 1029 USD per set. I'm looking to have more sets made and I could potentially offer complete sets for around 900 USD.
Might seem like a lot of money for studs compared to the regular ones but considering what needs to be spent to make a reliable high hp 3.0l 16v engine this is IMHO a given investment and potentially what will allow us to get into the 900 hp range without sealing issues.
Info about the material:
Custom Age 625 Plus®: This newly formulated super-alloy demonstrates superior fatigue cycle life, tensile strength and toughness – with complete resistance to atmospheric corrosion and oxidation. ARP is the first to develop manufacturing and testing processes for fasteners with Custom Age 625+. Best of all it is less expensive and expected to soon replace MP-35 as the material of choice in the high strength, super-alloy field. Typical tensile strength is 260,000-280,000 psi.
These studs have raised the bar for other engine types.
These will be made for 3.0l 16v and are in 9/16 which means you will have to tap the block to fit these.
Any interest?
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968cabturbo (09-29-2020)
02-02-2017, 08:25 AM
#2
Addict
Rennlist Member
Rennlist Member
I'm interested in your 9/16 16V set when you buy 625+ 
02-02-2017, 10:50 AM
#4
Nordschleife Master
Thread Starter
Well one alternative is to weld the head to the block as Porsche did with some of the old 917's 
But then these bolts are a super easy cheap fix lol.
But then these bolts are a super easy cheap fix lol.
02-02-2017, 10:57 AM
#5
Rainman
Rennlist Member
Rennlist Member
i'm thinking a tab of some sort added to both block and head, mid-point on each cylinder on both intake and exhaust sides.
so it'd be more "stretched hexagon" than square pattern of current studs.
so it'd be more "stretched hexagon" than square pattern of current studs.
02-02-2017, 11:22 AM
#6
Addict
Rennlist Member
Rennlist Member
Maybe pankl could come up with custom studs..
02-02-2017, 11:37 AM
#7
Nordschleife Master
Thread Starter
I'm sure other companies can make custom studs and there can be other ideas in regards to sealing the head but let's not go off topic please 
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02-02-2017, 11:54 AM
#8
Rainman
Rennlist Member
Rennlist Member
Has your head gasket been any more survivable with the aftermarket studs?
Something you might find interesting is that the Lord of All Things 928 thinks ARP is junk and only uses stock Porsche studs in his builds...
https://rennlist.com/forums/928-foru...ml#post7662616
Something you might find interesting is that the Lord of All Things 928 thinks ARP is junk and only uses stock Porsche studs in his builds...
I was unfortunate enough to be building 944 Turbo engines when ARP started making studs for those engines.
The head gasket problems got much worse, when using those studs, than the original studs ever were. On top of that, they insisted that you re-torque the studs once the engine got ran through a heat cycle. Pulling the cam carrier off a 944 is not much fun, just to retorque the hardware. Pulling both cam carriers off a 928, to retorque the head nuts, isn't ever going to happen, in my shop....I can barely stant to do it once, per engine.
The Porsche hardware stretches, by design. This keeps the head "clamped" to the block as the engine warms up and cools down...it is always clamped. The ARP hardware is very high quality and doesn't stretch much. The "clamping" doesn't work as well. The result is more blown gasakets...not less!
I've got huge box of ARP hardware that I've removed out of 944 engines, around here, somewhere. Scrap metal.
The head gasket problems got much worse, when using those studs, than the original studs ever were. On top of that, they insisted that you re-torque the studs once the engine got ran through a heat cycle. Pulling the cam carrier off a 944 is not much fun, just to retorque the hardware. Pulling both cam carriers off a 928, to retorque the head nuts, isn't ever going to happen, in my shop....I can barely stant to do it once, per engine.
The Porsche hardware stretches, by design. This keeps the head "clamped" to the block as the engine warms up and cools down...it is always clamped. The ARP hardware is very high quality and doesn't stretch much. The "clamping" doesn't work as well. The result is more blown gasakets...not less!
I've got huge box of ARP hardware that I've removed out of 944 engines, around here, somewhere. Scrap metal.
02-02-2017, 01:50 PM
#9
Addict
Rennlist Member
Rennlist Member
Why do you think the strongest 944 headstuds should come from arp? Raceware, pankl and such could be a better option, have you contacted them too?
02-02-2017, 07:24 PM
#11
Rennlist Member
I'm interested, but what length would they be? Ideally, I'd want 150mm for the 89 block/head, though suspect you are looking for 165mm and most 951 guys need 190mm. Also, have you considered the large Milledge studs, which last I checked are still available from Jason Lee in Florida. They are made of a austenitic super-alloy as well. Jason could tell you how the alloy compares to Custom Age 625+, but believe they're in the same ball park anyway without needing to do such a small custom run.
02-03-2017, 06:21 AM
#12
Nordschleife Master
Thread Starter
Some facts about the material:
* The regular ARP bolts and Raceware bolts are 180000-210000 psi tensile strength.
* These Custom Age 625+ are 260000-280000 psi.
* To put this in perspective, the Heritage motor (similar to JME?) super alloy austenitic bolts are 2400000 psi.
Info about the custom sets I'm about to order:
* 165 mm length for 104 mm blocks with 16v head.
* undercut design - this is important!! This means the studs have a reduced diameter around the middle. This will allow the bolt to stretch at this point instead of in the thread. This reduces stress in the block.
I won't go into battling the misconceptions from the 928 thread. Let's just say these larger head studs are proven to raise the power level at which head lift occur on these engines. So far it has been successful with 180-210 k psi studs and by upgrading to the CA625+ material we should be able to raise the power level a bit further.
* The regular ARP bolts and Raceware bolts are 180000-210000 psi tensile strength.
* These Custom Age 625+ are 260000-280000 psi.
* To put this in perspective, the Heritage motor (similar to JME?) super alloy austenitic bolts are 2400000 psi.
Info about the custom sets I'm about to order:
* 165 mm length for 104 mm blocks with 16v head.
* undercut design - this is important!! This means the studs have a reduced diameter around the middle. This will allow the bolt to stretch at this point instead of in the thread. This reduces stress in the block.
I won't go into battling the misconceptions from the 928 thread. Let's just say these larger head studs are proven to raise the power level at which head lift occur on these engines. So far it has been successful with 180-210 k psi studs and by upgrading to the CA625+ material we should be able to raise the power level a bit further.
02-03-2017, 01:10 PM
#13
Rennlist Member
Yes, when I called Milledge for his studs, he sent me to Heritage, and Jason told me he and Jon developed them together. Sounds like the ARP material is even crazier. I'll PM you...
EDIT: Duke, your PM mailbox is full...
EDIT: Duke, your PM mailbox is full...
02-03-2017, 02:00 PM
#14
Nordschleife Master
Thread Starter
02-03-2017, 09:03 PM
#15
Rennlist Member
I think I'll grab a set too please Gustaf.