ARP Main bolts or no? And if so, linebore?

[bugjam1999]

Hi all,

A bit of advice please- I’m rebuilding a b230fk aiming for 300bhp and (amongst a load of other parts) I’ve bought arp studs for the main bearings, but I’m wondering if they’re required and if so how to go about installing them. The overboost racing rebuild series on YouTube uses the standard main bolts for a 600bhp build, which is way over what I’m aiming at. That said, I’ve bought them now and there’s no point them staying in the box, so I may as well install them.

Do I need to have the block line bored with the arp main studs installed? I’ve read a few threads suggesting the main caps should be installed and the app studs torqued higher than stock, then linebored as the higher torque will deform the caps.

Or install as direct replacements using standard torque settings?

I have one of the replacement oil transfer tubes that will clear arp main studs.

Thanks all,

Cheers

 

[mikep]

No line bore needed, and you can always sell or return them.

 

[linuxman51]

I didn't use them at 600hp nothing looked bad in the bottom end nor was there any signs in the oil or filters indicating problems brewing.

 

[culberro]

First off, don’t under torque studs. You will not get the appropriate stretch needed to keep them tight.

I’m of the opinion and experience that you’ll want to at the very least check the main bores before (torqued with stock bolts) and after (studs and girdle) to see how much deflection you have.

Main studs are notorious for distorting the main bores, and these can often be cleaned up with a line-hone. This is much less then a main line-bore and hone.

You’re also going to distort the cylinder bores with the main studs, so you have that to worry about now too

 

[cwdodson88]

I was toying with the idea of doing a combined billet girdle/crank scraper, and what culberro just mentioned is one of the top reasons why I said nope, followed by what linuxman said.

For some things it’s worth the effort, but in most cases… it might not be.

 

[bugjam1999]

Think I’m leaning towards using the standard main bolts based on comments above…