Arp 2000 headbolt limits

[Dan ep3 turbo]

Could any one tell me when arp2000 head bolts become to weak? I've read on evolution m around 700whp and 40+psi but just wondering on people's opinions over here?

Thanks

[Kevin Troy]

AFAIK the APR2000 are the rod bolts.

[Dan ep3 turbo]

Originally Posted by Kevin Troy

AFAIK the APR2000 are the rod bolts.

No there not arp2000 is the grade/material of the fastener

[Andrew B]

Generally in the uk 550 upper limit

Get some nice H11 in there

[kins]

Originally Posted by Dan ep3 turbo

Could any one tell me when arp2000 head bolts become to weak? I've read on evolution m around 700whp and 40+psi but just wondering on people's opinions over here?

Thanks

It wouldn't be smart to try and relate fastener strength to horsepower and boost pressure.

ARP state tensile strength figures for their materials and pressure for which clamp load can be maintained.

ARP2000 can achieve clamp load at 220,000 psi.
Cosworth H11 studs are 260,000psi.

Edited to add - ARP L19 material is also 260,000psi... H11 and L19 - obviously trade names could well be the same material under different badges.

[foreskin fred]

The stock head bolts work perfectly.

They're not the weak point unless you're in the business of selling parts.

It's the head which distorts under extreme pressure and lifts between the bolts.


Edit 'cos I'm out of posts.

Aluminium is softer than steel. Over many heating / cooling cycles , the aluminium under the headbolt washer flows away from it............it's "ductile".
The bolts go loose.
Replacing with studs fixes HG leaking problems.
So does re torquing the head and it costs nothing and it's a lot easier.
That's IF you do it early enough before you do any other damage.

[Dan ep3 turbo]

Originally Posted by foreskin fred

The stock head bolts work perfectly.

They're not the weak point unless you're in the business of selling parts.

It's the head which distorts under extreme pressure and lifts between the bolts.

Do you go on evolution m a lot? That's what I've seen on there to

[Dan ep3 turbo]

Originally Posted by kins

It wouldn't be smart to try and relate fastener strength to horsepower and boost pressure.

ARP state tensile strength figures for their materials and pressure for which clamp load can be maintained.

ARP2000 can achieve clamp load at 220,000 psi.
Cosworth H11 studs are 260,000psi.

Edited to add - ARP L19 material is also 260,000psi... H11 and L19 - obviously trade names could well be the same material under different badges.

The Americans don't seem to mind quoting a power/boost number on head bolts, but they seem a lot more experienced on pushing the limits over there. I'd imagine ignition timing around peak torque is the killer when cylinder pressure is at its highest ismore than likely the main issues

[kins]

The OEM head bolts are fine to a point and aftermarket head studs have their place when limits are pushed. To say they are not required at for certain applications would be ridiculous.

Americans can say and claim a lot of things (especially on the forums) but it doesn't mean they or their claims are always correct.

[kikiturbo]

Originally Posted by kins

It wouldn't be smart to try and relate fastener strength to horsepower and boost pressure.

ARP state tensile strength figures for their materials and pressure for which clamp load can be maintained.

ARP2000 can achieve clamp load at 220,000 psi.
Cosworth H11 studs are 260,000psi.

Edited to add - ARP L19 material is also 260,000psi... H11 and L19 - obviously trade names could well be the same material under different badges.

to be precise.. ARP doesnt state clamp load nor the pressure for which it can be maintainded..

22000 and 260000 psi is tensile strength not clamp load. It only indicates how strong a bolt is. More tensile strength means that you can apply more clamping load (i.e. more preload by bolt torque) on headbolts if you choose to do so. More clamping load means more block distortion too...
This all means that there is no real proof on which bolt does what, only builder experience that dictates which combo works at which power level..

[beliblisk]

Nicely written kiki

[Kevin Troy]

Master Kiki

[Arronevo8]

Oh! Kiki I love it when you talk dirty

[philip2]

Just stripped an evo 8 running 620bhp that when checked over its shown signs of the head lifting along exhaust side of the block and split gasket between 3 and 4. Thats on arp2000 headbolts.

I wouldnt run more than 550bhp on arp2000 headstuds

[Dan ep3 turbo]

Originally Posted by philip2

Just stripped an evo 8 running 620bhp that when checked over its shown signs of the head lifting along exhaust side of the block and split gasket between 3 and 4. Thats on arp2000 headbolts.

I wouldnt run more than 550bhp on arp2000 headstuds

What turbo was the car running? From what I've researched aggressive ignition advanced at peak torque is the real killer