ARP Head & Main Studs ... problem?

Hi,
I change my head gasket by Cometic Multi-Layer Steel, and I put to have a good engine ARP head and Main Studs.
I grip in first time with the standart clamping (80Nm), after 2000kms, when I drive fast, I've got a lot of pressure in coolant tank cover and cooled water 's going out by the security cap.
After lot of trying, I grip again ARP and I would surprise all one at 50Nm.
I grip again at 90Nm and after 5000kms I think I have to grip again !!!

Someone have got the same problem?
What I have to do?

ps: Sorry my english is not good...

Did you or someone else do the build?

Bonjour!

your english is not that bad at all. Lot better then mine after a 12 pack or a night out with Jack. :tongue:

you have to go back and re-tighten them down.

on some cars, its unnecessary, on others you need to go back and re-TQ them. Personally i have not had problems with them or need to re-TQ but i follow directions to the T.

also when you installed them, did you follow install directions to the T?

use the assembly lube that went with the studs?

you can get 30-40% less tq on them if you install them dry or with just engine oil and not the specific assembly lube provided.

I'm doing all myself and yesterday I check all ARP and the pressure in the cooler tank cover and all one is "ok", I just be afraid to grip everytime all ARP.
Thanks for your answer, I think is normal to re-grip ARP head after 2000kms...
Now, I don't know why my climat inside give me sometime cold and sometime hot, not medium....

My english is good when I take two "Pastis", it's the only thing to speak with you....:tongue:

samsam13 said:

Hi,
I change my head gasket by Cometic Multi-Layer Steel, and I put to have a good engine ARP head and Main Studs.
I grip in first time with the standart clamping (80Nm), after 2000kms, when I drive fast, I've got a lot of pressure in coolant tank cover and cooled water 's going out by the security cap.
After lot of trying, I grip again ARP and I would surprise all one at 50Nm.
I grip again at 90Nm and after 5000kms I think I have to grip again !!!

Someone have got the same problem?
What I have to do?

ps: Sorry my english is not good...

Click to expand...

OK , your problem is the part where you torqued (clamping?) "at" 80 "Nm"
It should be 80 Lb/Ft !
even 90 Nm is only 66 Lb/Ft!!
You need 110 Nm!!!!!!
YOU MIGHT need new headgaskets now! At least re-lube the washers and nuts and re-torque.

On the NSX manual I have 56lbft / 78Nm for Cylinder head bolt (1991servman.pdf page 80)

ARP should have their own specs, but either way, I would torque to 80ft/lbs as our results speak for themselves.

After 15+ dyno pulls at 25psi and several pulls over 30psi(our current 920whp), our heads are still bolted down. This is without mentioning the nearly 32,000KM of daily driving, track driving, and of course the dyno pulls. Same gaskets, same studs that you are using.

Just my $.02 FWIW.

i was just cursing the internet and found some info that could help you

http://www.aa1car.com/library/ar996.htm

http://www.aa1car.com/library/2005/ic010532.htm

people are recommending 15-30 RMS for surface smoothness for the MLS head gaskets to work good.

almost a mirror finish.

read the 2 articles above, i got lots of new updated info from them.

also i TQ my ARP head studs to 80. ARP recommends 65 via their directions but 80 goes the trick best. Use ARP assembly lube or you'll be under TQ.

having to do the HG multiple times is not fun or cheap.

good luck with your build & happy new year