reusing main cap bolts

[belaggi1k]

Hello everyone!

My first post is going to be most stupid question of the year. To cut to the chase i am running an ASJ engine that had rod bearing damage and after sourcing an std crank and new rods and bearings the engine got back together and i've been running it for a year, but now one of my turbos is on its way out and I am considering going with rs6 turbos, however I've made the stupid mistake of re-using the original main cap bolts when the engine was put together and torqued them to factory specifications (with the additional 90 degree turn in the end). I know these are torque to yield bolts and I have no idea why I did not buy new ones at that time, but it is what it is now. Did anyone ever re-use these bolts on higher powered engines? I am afraid of putting more stress on them. I am thinking about replacing the bolts in-situ with new ones one-by-one without removing any of the caps. What do you guys think, what should I do?

Thank you for the input!

[LightningLou]

They are definitely TTY bolts. I would change them if you can to prevent any further issues down the road if one were to fail, because that would be catastrophic. Buy some new ones or some studs that you can re-use over and over and have the peace of of mind that everything is buttoned up properly down there.

[CELison]

buy ARP main studs and call it a day.

[belaggi1k]

I'd rather not go the ARP way because that would mean a complete disassembly of the block to get the caps line honed if necessary, however I think it might be okay to just replace the OEM bolts one by one after just removing the oil sump and that should not take more than a couple of hours because the engine will be out for turbos anyway. I've asked this because I know some local people who re-use their TTY bolts on their 4 cylinder engines for like 5 times and the engines are pushing more than double their original power without issues. It's weird :(

[landfill]

You shouldn't have to get your mains line honed just for the studs. That's only required when running aftermarket main caps or caps that weren't assigned to your block. The only mod needed I'm aware of for running arp main studs is to clearance the upper oil pan for the areas that contact the studs. Not really a tough job. Either way out of all of the TTY bolts used on a vehicle I'd have to say the last two I'd want to skimp out on would be head bolts or main bolts. Definitely not worth taking a chance.

[Zba]

Either way out of all of the TTY bolts used on a vehicle I'd have to say the last two I'd want to skimp out on would be head bolts or main bolts. Definitely not worth taking a chance.

Rod bolts

[landfill]

I'll mail you some bolts if you send over some sopersetta from Venice lol.

[slow ride]

Anytime you use a stud or apply higher clamp load you should always measure the parts after. It is very common to need machine work.

[landfill]

Maybe on other platforms but I've been through a bunch of these motors. The main caps
fit fine every time when just swapping to studs so IDK? Sometimes on other motors some
cap mis alignment has occurred so you're correct their but for me never with a 2.7t.