Is it ok to reuse the stud and nut after they were used for around 10k ? Is there a stretch limit ? What actually causes the bolts to stretch ? Is it re-torqeing the bolt that cause stretch or just the amount of pressure on it constantly while running ? How would you measure this ?

 

i think one of the main points for using ARP studs is so that you can re-use them... as for the service limit or max stretch allowed, i'd contact some one at ARP.

the stretching though is the point of torquing bolts and studs. when you torque the studs you're stretching them.. when you loosen them again, they return to there previous state. ARP studs are designed to do this over and over without un-loaded stretching or fatigue.

 

You'll be fine reusing them.

 

great explaination. However I have a few more questions. To measure the stretch of the stud I would have to measure end to end by removing the stud correct ? Also should I have had before and after specs if I really wanted to be accurate ?

Also technically when the bolts are torqued they stretch but over a few times they should return to their previous state like you said. However will a bolt over time be unusable due to the forces of combustion on it ? Will that cause it to fatigue or stretch ?

 

a stretch gage is what you would use to measure the studs. this is the next level beyond using a torque wrench. i am unsure though how this would be done without being able to access the end of the stud...

you can measure before and after, maybe keeping a log of stud length over time and mileage. but you'll likely want to be looking at 0.001" variations, which means you'll need some pretty accurate measuring equipment.

i don't know engineering specifics for ARP, but i know they are presumably the best you can get and i know they've done their homework... i would speculate that their head studs don't even experience 10% of their yield strength in a running engine. you should be able to trust them for the life of the engine (...assuming this is not a dedicated competition engine- even then though, you shouldn't have any trouble.)

 

could you measure stretch from a fixed point such as the block deck ? Because stretch as far as a bolt being bad is measured without the bolt being torqued ? Since when using a rod bolt stretch gauge it is meaured while being torqued.

 

Unless they have been mishandled somehow, they are fine. Reuse them.

 

bump

 

So it seems the torque specs are the same when you reuse them?

 

Yep, what he said.

 

YES U CAN REUSE THEM ! and if u overtorq u might pull the threads out of ur block ! lol good luck with that budddy ! then u gotta pay like 30 - 70 a hole to fix hahah i fixed many !

 

im going to resuse mine when i put my head back on my new block.. now if i dont have arp lube what else could i use.. not tryin to thread jack

 

30w motor oil...like straight 30w, not 10w-30. and search to find the torque since it more when using oil.

i have no idea how threads like this go for soo long since it should be locked and deleted a long time ago.

 

You could use non-metallic anti-seize, http://www.huntvac.com/products.php?id=68&t=series

or just get some new ARP lube