Thread: ARP Studs or Stretch Bolts

I've rebuilt two crossbolted engines, one 4.6 one 4.0 I used ARP's on the 4.6 and used (as in re-used) stretch bolts on the 4.0 neither had a problem.. I'm building a 5.0 based on a stroked 4.6 and I'm going to use ARP head studs on it.. I just want to be sure.. I don't know what it's like over there but here the new stretch bolts cost as much as the ARP kit..

Keith

with ARP's reputation and QC I'd be going that route.

Thanks Keith.

The stretch bolts are torque to angle. What did you do with the studs? Did you use the same torque for the studs (with a composite gasket) as specified for earlier engines without TTA bolts and a steel gasket?

As ARP don't produce a kit specifically for the 10-bolt head cross-bolted block, I assume you bought the 3.5 litre stud kit, i.e., the ARP 124-4003 studs. (Do they come with washers and nuts?)

Do ARP specify the torque for these or does one use the factory spec?

Sorry for being a bit vague on this.

All the best

Ron

Originally Posted by p38arover

Thanks Keith.

The stretch bolts are torque to angle. What did you do with the studs? Did you use the same torque for the studs (with a composite gasket) as specified for earlier engines without TTA bolts and a steel gasket?

As ARP don't produce a kit specifically for the 10-bolt head cross-bolted block, I assume you bought the 3.5 litre stud kit, i.e., the ARP 124-4003 studs. (Do they come with washers and nuts?)

Do ARP specify the torque for these or does one use the factory spec?

Sorry for being a bit vague on this.

All the best

Ron

I would imagine they would supply their own torque figures with the stud kit. ( they did with some arp rod bolts ive used in the past) the torque / angle settings are for the bolt / stud and not the heads benefit.

btw - is an alloy block up to the extra stress a stud will impose? a mate had to helicoil a bbc as the studs pulled out of the cast iron block. (was a very old and well used block tho)

also iirc - a different hone procedure is required when using studs. ??? torque plate?

anyway, factor in the extra costs of getting the bores honed with torque plates fitted, bolts will prob work out cheaper.

Indded the ARP 'kit" I got was for a 3.5 (actually a 215 Buick) A buddy of mine picked it up and never used it, It came with everything needed and detailed instructions about the use of oil and torque specs. It was designed for a Steel Gasket but I used the composite one's. It's held for some 40,000 really abusive miles..

Check out the website it's very informative..

http://www.arp-bolts.com/Catalog/Catalog.html

Keith, that's great info. I have been on their website recently and read a lot of stuff but wanted to hear from someone with real world experience.

A few Rover V8 specialists, e.g., RPI, JE Engineering, etc. recommend them. Dave Hammill talks about them in his Rover V8 book but not in respect of the torque specs for different gaskets, etc.

Ron

Originally Posted by PLR

Why/how does a stud exert more stress ?

Something i need to understand as i though the torque bolts would be worse than studs

Ditto.

Crossy's comment about additional stress from studs, that didn't make sense to me. The stud probably screws in further than the bolt so would have more engaged thread in the block holding it so it should be less likely to pull out.

Re the torque plate, I'll ask about that.

Ron

You get less stress from studs, and can use a higher torque figure.
I have read quite a bit about them for main bearings, to the extent of if you use them you have to have the block line bored, as they hold the caps so much more tightly.
BUT I would be wary of using them for heads, as it is impossible to remove the heads of a RRC with studs. I do not know about a 38A. And do you really want to remove 20 studs to lift the heads? Remember you have to remove the lot, as its the interference with the firewall that is the problem. In fact on an RRC , I doubt that you could not get the back studs out with the engine in place.It would be a PITA.
I have not eyeballed a 38A, but you better be sure before you do it!!!!LOL
Bolts hold the heads quite well enough . It is overheating that causes gasket failure/block cracks not bolt failure.
Regards Philip A