m20 arp studs

[Cyrix2k]

anyone have access to an engineering lab that can run tests on the ARP & MCMaster studs? mostly when plastic deformation occurs.

[TS87325IS]

Nahh.... im going to give them the good old 18to20 lbs of boost test though..lol

[germanrob82]

Closest thing is Black-Oxide M10x1.5 150mm Length Spacer Stud. McMaster-Carr Part # 93275A046 = $2.79/ea

http://www.mcmaster.com/#catalog/118/3177/=h5f0uj

EDIT: Hmmm.. looks like ARP head studs are also Black-Oxide steel.. if these work then lots of people have been getting butt raped @ $225 a pop.

OKAY HERE'S WHAT I FOUND OUT....

The McMaster Carr's have a tensile strength of 125,000psi and rockwell hardness of c27

The ARP2000's have a tensile stregth of 220,000psi and rockwell hardness of c46

I haven't double checked yet but I'm almost certain I remember the metric blues being around the same figures as the McMaster Carr's.... and they cost half as much

[jaywood]

Metric blues have a Class 4g6g thread fit, a minimum Rockwell hardness of C38, and minimum tensile strength of 176,900 psi.

[TS87325IS]

Metric blues are definatley not reusable just incase anybody wants to know. Im going arp.

[jaywood]

Wait, so no more mcmaster studs?

[TS87325IS]

Not gonna chance it if there is that much difference in the two.i allready had a metric blue broke off in the block, dont want to do this again.

[RobertK]

Not gonna chance it if there is that much difference in the two.i allready had a metric blue broke off in the block, dont want to do this again.

I honestly doubt you would have the same problem with the studs. Worst case you strip out the threads or nut. I wouldn't hesitate to use them. I actually plan to use them on my S52 refresh.

There is a difference in that that bolts are pulling in their center and studs / nuts utilize more downward clamping force.

[einstein57]

Factory bead bolts are stonger then those studs. I would not use them.

[germanrob82]

oem bolts are comparable and metric blues are quite a few rockwells stronger and still stretch the bolts. So comparing claming force versus tensile strength is pointless. The stud itself will stretch before the nut and spacer give out causing the head to lift and so on and so forth.... reguardless of what the clamp force style is so its a really mute point.
I'm going with ARP studs: http://www.ebay.com/itm/BMW-M20-ARP-...item48416c90e0

[RobertK]

oem bolts are comparable and metric blues are quite a few rockwells stronger and still stretch the bolts. So comparing claming force versus tensile strength is pointless. The stud itself will stretch before the nut and spacer give out causing the head to lift and so on and so forth.... reguardless of what the clamp force style is so its a really mute point.
I'm going with ARP studs: http://www.ebay.com/itm/BMW-M20-ARP-...item48416c90e0

You make a very good point and the difference in tensile strenght is reflected in the price.

Oh well, back to the drawing board.

[JCarp90]

My metric blues will be here tomorrow and my engine will go together this weekend. We shall see...

[blueapplesoda]

Yeah...stick with Blues. Those studs look promising if they made it in a 12.9 class.. Or just do ARP, those are proven time and time again.

I put metric blues in all my turbo kits as a "at least" precaution, with special install instructions. Just clean the holes really really well. I usually fill it up with some sort of solvent and use a pipe cleaner and aggitate it for about a minute, then use a shop vac attached to a home made gatorade bottle catch can and vacuum lines to suck out all the stuff in the holes before installing. Use good moly type grease/assembly lube.

It's floating around on these forums, but Information, which should always be free.

ARP PNs
M20 HSK part numbers:
14x AM6.770-1B
14x AMN12-1
14x 200-8519

Derek
DedericMS

[TS87325IS]

My arp's came today ;-)

[4evere30]

go metric blues ! im going to buy some of those soon , very disappointed when a ARP stud broke off in my block! BIG waste of money , way over priced
called arp about it and they wouldnt send me a new stud to replace the broken one