7 bolt ARP head bolts

[caged]

Hey iv some how been given Arp head bolts instead of studs. Iam uming and arring about just using them. Its a 7 bolt evo 3 engine going for 550whp with an HX40 pro. would you use them or buy new studs? They look the same as the studs but are just bolts. Does anyone know what to torque these up to? Arp doesnt have them on there site and it didnt come with instructions. Cheers Josh

 

[crimsondragon]

It says ARP on the bolt head and is 12 point? If it isn't, they're not ARPs. Get another box.

 

[TSITurbo95]

ARP Head studs only come in studs, the stock 7 bolt head bolts are bolts. And yes, if they don't say ARP on them, then they are not ARP. Also, there is a handful of people who pushed stock blocks past the hp you wish to reach. How reliable is it, no one knows. Every motor is different.

 

[99gst_racer]

Pics please. ARP doesn't even list bulk bolts in 11mm, so I have no clue what you have there.

 

[caged]

They are definitely 12 point Arp head bolts. They are stamped arp and came in an arp box that had arp head bolts printed on it. When I'm back form work in 1.5weeks ill get the pics and part number.

 

[99gst_racer]

Well, 12mm is for 6-bolts. All 7-bolt engines use 11mm.

Post the part number on the box when you get a chance.

 

[caged]

12 point head not 12mm thread. They are 11mm.

 

[99gst_racer]

Oops, sorry, I misread.

But let us know of a part number when you can.

 

[snowborder714]

I'm guessing it's 207-3900.
ARP 207-3900 - ARP Pro Series Cylinder Head Bolt Kits - Overview - SummitRacing.com

Now, whether I can find a torque spec listed somewhere is a different story. Maybe someone can contact ARP and get an answer.

 

[99gst_racer]

I'm guessing it's 207-3900.
ARP 207-3900 - ARP Pro Series Cylinder Head Bolt Kits - Overview - SummitRacing.com

^^^ Incorrect image I assume?

Now, whether I can find a torque spec listed somewhere is a different story. Maybe someone can contact ARP and get an answer.

Torque specs are based off of material type, diameter, and lubricant, so it should be the same as the 11mm studs.

 

[caged]

That would be them I think. Thanks for that. I would call up arp but being in a different country and time zones makes it hard, I think ill try email them. Next question is would you use them? They appear to be made from the same material as the studs so I'm just assuming they are just not as accurate to torque as the studs, would that be the only negitive?

 

[snowborder714]

I'd assume so as well, Paul. I saw the same image on a few other sites. The specs say it's a 12 point head.

Good to know on the torque spec info.

 

[99gst_racer]

I've never noticed that ARP came out with a head bolt for the 7-bolt 4G63. This is news to me. It appears that it's an undercut bolt as well.


caged - I'm sure they're fine to use, but I'd still take a stud over a bolt any day of the week.

 

[caged]

Just found out that the ARP site has become usefull since I used it last. torque spec is 80ftb. Cheers