Reusing Rb25 Headbolts

[joe blo]

hi guys wondering if i can reuse my rb25det headbolts that were new last time. the motor failed early so the bolts are new sorta.

the car only did like 250-300kms. were done up for a few months. didnt get to do the retighten

rekn theyd still be any good? they copped one dyno run of 450rwhp. then pistons broke

[kitto]

IIRC they should be ok to use again. Once.

I've reused RB20DET ones before.

Its RB30 bolts that can't be reused.

I once asked myself the same question, did some internet research and from what i remember, yes; RB20 and RB25 bolts can be reused.

[Room42]

Mate its like this. Most head bolts are torque to yield. That means they get done up once and are stretched and twisted at the proper torque setting. They are fine while they are done up. After you undo them you cant reuse them. There is no difference if they are 2 weeks old or 20 years old.

Ok sure you physically "could" use them but head bolts are only $70 a set. You would not rebuild an engine and not buy new head bolts to save $70 bucks.

It a bit like oil. You wouldn't buy $14 supermarket oil just to save $70.

This time get a someone to build your entire engine with forged pistons and get a warranty with it. Or get an already built R.I.P.S engine for under $8k.

[Dobz]

Get new bolts. The bolts stretch and twist when they're tensioned so once you pull them out they don't have the same tensile strength they had from new. If you'r running around 450hp then a set of arp head studs would add some insurance.

And kitto how is it you can reuse rb20-25 bolts but not rb30? They're exactly the same apart from the bolt length.

Edited November 6, 2011 by Dobz

[kitto]

And kitto how is it you can reuse rb20-25 bolts but not rb30? They're exactly the same apart from the bolt length.

That was the info i was given 2 years ago or so from several people when i asked that question... Odd you say, yes i agree.

I opted out for new bolts for that head change anyway as i had the time to wait for new ones to come in.

I've reused them before in an urgent get it done situation and had no issues. it wasn't a 330kW engine however.

Personally, to do it right, i'd put new head bolts in.

On another note, if its a 330kW engine, and i would assume your running a metal head gasket, why dont you put a set of ARP studs in?

[joe blo]

its standard pistons again and genuine nissan headgasket. getting different shop to tune it. talked to one of the main skyline guys and he said 450rwhp should be fine but get the guys im using this time to tune it

yer ok il get new ones

Edited November 6, 2011 by joe blo

[joe blo]

what would be likely to happen if i reused them?

i reused them on a rb30 turbo motor a few years ago with 300rwhp. was ok while i had it but didnt use it much before i sold it so dunno how it went

[Room42]

what would be likely to happen if i reused them?

i reused them on a rb30 turbo motor a few years ago with 300rwhp. was ok while i had it but didnt use it much before i sold it so dunno how it went

If you reuse them then there is a high chance the bolts wont hold the proper torque settings. This means the head gasket will blow quickly.

[JonnoHR31]

they're fine to re use, just make sure they're torqued properly and go over all of them 2-3 times at the end.

yes they stretch but if they were f**ked after one use nissan would specify them as replaceable after every disassembly. have re used my standard bolts 4 times now with ~300rwkw and no problems whatsoever

[Room42]

As I already said torque to yield bolts should be used once. It is irresponsible to get on a forum with the high standing of SAU and say that it is fine to use head bolts 4 times.

Edited November 6, 2011 by Room42

[badhairdave]

Nice high horse you have there.

Attachment...

Yes i know it's from an SR manual, it's all i have available on the work computer.

RB one will say something similar.

If you don't have the gear to measure it then replace them.

They do not necessarily need to replaced.

Pages from em.pdf

[boostn0199]

Itll probably be fine but like anything theres always a chance it will fail kind of like not changing tensioners and idlers when doing belt prob wont fail but you never. Personally whenever i have made decisions on not changing where it is recomended it always eats me up inside like you dont know if its suddenly going to break lol so now i dont care and always be safe and change where things are at chance of failing.

[Room42]

Hey dave f**k off with your smart arse high horse shit. Every time you take your car to a professional you will get new head bolts with your head gasket. Plenty of mechanics won't even fix your car if you ask them to cut corners like that. Cutting corners is stupid. But if that is what you want to do then go hard.

[GTScotT]

Take this as a grain of salt.

In the history of how many motors Ive worked on, two have snapped brand new head bolts when torquing up..

In my frustration I reused the original bolts and all were happily ever after.

Note: they were the only two motors I ever put new bolts into

[BMYHOE]

im getting the popcorn out

[joe blo]

so they are stretch to yield bolts?

[GTScotT]

they are meant to be

[JonnoHR31]

As I already said torque to yield bolts should be used once. It is irresponsible to get on a forum with the high standing of SAU and say that it is fine to use head bolts 4 times.

go read the service manual, no mention of any need to replace them. and no, nissan aren't idiots.

having said that, it is a good idea to replace them, but its not essential, 99.9% of old ones will work fine.

[koe]

but thats for oem boost levels.Greater boost levels require tuff stuff.I would do the MLS,Aftermarket timing belt and arp head studs atleast.

There is no reason to take chances.The basics is to build reliable power.

[boostn0199]

I seem to remember reading somewhere arp head studs dont have to be changed is that true?