stock main bolts or ARP main studs?

[dsmcurse]

so i have a fully built engine, (well almost) eagle rods, ross pistons, all clevite bearings. crower 272's, hx40 turbo, 310lph pump, 1000cc's, dsmlink V3, all supporting mods. i currently have the engine on a engine builder stand upside down with the oil pan off.

my buddy tells me now is the time to switch from the old stock bolts to new studs.
my honest realistic goals are about 450-470awhp which is maybe about 550-560 engine power.

will my stock mitsu main bolts work for this? everytime i've ever taken it apart i check for strech and the i put that exact bolt back into its original hole. is that ok? i have arp head studs and arp rod bolts. should a spend the 80bucks or whatever to do arp mains too? or do you think the mitsu main blots are trust worthy for my power goals?

i understand that at a tremendous amout of load the main bolts could MAYBE stretch and i'd loose main bearing tolerances. but at like maybe 550ish engine power do you guys think thats a possibility? while its apart should i make the switch from bolts to studs? thanks

 

[eeeewidner]

Studs most definitely. You could always install Kiggly main girdles for added support of the bottom end. That is if you are built engine is a 6 bolt.

 

[turbo98eclipse]

Keep in mind arp mains USUALLY require you to align hone the crank bores.

 

[eeeewidner]

Keep in mind arp mains USUALLY require you to align hone the crank bores.

Good catch. I had to do that when I built my engine.

 

[mike hobbs]

I would do the arp since your already there with the build, might as well do everything to it. You don't have too but I would do it

 

[dsmcurse]

whats the best and easiest way to tell if it needs align honed? take to a machine shop? can it be as simple as just screwing in the studs hand tight like you do the head studs? i really dont want to rip it all the way down to take to machine shop. i was hoping i could just swap from main bolts to main studs and have it be that easy. any more advice on having the crank's main's align bored. if you guys are confident in stock mitsu crank bolts holding power in the 550ish neighborhood then im gonna still use the stock bolts

 

[Mr Peepers]

More clamping force from the ARP studs can distort the main bores. Same reason you need to recondition the rods when you install ARP rod bolts.

I'm also somewhat curious at what point the mains need to be replaced with different bolts/studs. Seems like a direct correlation with torque but I could be off.

 

[Miasma]

When you install arp main studs, it's a good idea to fully disassemble so you can torque down the mains and measure the hone for distortion. Other option, possibly easier for you would be to use plasti gauge and measure the oil clearances on each main journal after installing arp studs. Follow the torque spec recommendation provided by arp.

In not all cases do arp studs distort your alignment hone, but it is common and recommended to have it machined to prevent any costly problems down the road.

As for your goals, you could get away with using oem mains but it seems like the next step for the build so why not do it.

 

[grothe3297venge]

This was wayyy back in 2011.. I hope it's not on an engine stand still...

 

[4G63gst1990]

I would say arp main studs with algin hone just for the added strength