Stretch Head Studs ?

[tricstar]

question for the engine builders and knowledgable..

just recently brought a GTR with built RB28, first time we put it on the dyno it split a wastegate hose and hit boost cut at over 30psi, now there is a tiny oil leak under the exhaust manifold between the head and block, been told its probibly stretched the head studs and we need to remove head to replace studs and get head checked etc etc

Excuse my ignorance for knowing f### all, but can't the head just be re-torqued ???? car still runs perfectly

If the above is needed, how would I expect to pay ?

[StealthX]

I'm no engine builder, but you'd want your head studs to be as top spec as possible. They're not THAT expensive, after all you don't want be cruising down the road and pop a head gasket, then have to fork out more to rip the head off, just cos you skimped out on the studs...

I say if they are in anyway damaged at all, replace them. Who knows, they might just need re-torquing, but i doubt it if the head has lifted enough to cause a leak. I'm surprised you didn't damage the bottom end at all, if boost was that high, how didn't you get heaps of detonation and end up with killed pistons?

Sorry to answer a question with a question, but why wasn't the boost monitored? i.e. surely the tuner saw that the boost was increasing out of sight, why didn't he stop the run when boost was spiking out of control?

Excuse my ignorance for knowing f### all,

Don't apologize man! That's what this forum's about!

[R31Nismoid]

You need new studs, end of story.

You cannot just do them up tighter and hope for the best.

[TiTAN]

you can get ARP studs for ~$250 + what ever labour it takes to fit them.

[tricstar]

just got off the phone from the workshop, after a more thorough inspection they are leaning towards a wrongly machined block or head , slightly to much removed on the outside of the oil gallery that feeds the head....only the smallest leak atm, not to many options with this one, not far off a full rebuild, pretty piss poor, engine has done less than 5000km and cost the previous owner over $50k

we're going to try chemi-weld or something similar as a patch, ( because I only just bought the car and can't afford a rebuild straight away

very pissed off

[Deano 1]

if your changing the studs i think youll have to do teh head gasket as well. im 99%sure you can only torque a head gasket down once.

[Deano 1]

BTW how much power did it make at 30psi?

lol

[tricstar]

BTW how much power did it make at 30psi?

lol

not sure, but at 25psi it makes 760hp at the motor

[N1GTR]

What turbo/s?

[tricstar]

What turbo/s?

HKS step2 2.8 stroker, full counter crank and rods kit, CP pistons.

Brand new head from Nissan, Jun 272 in and ex cams, 10.8mm(?) lift, special retainers and all the jazz needed to support the cams and high revs, heads extensively ported.

Big dollar hypertune plenum and single throttle body setup

Custom alloy breather tank etc

Jun oil pump, N1 water pump, cant recall the brand of balancer, but its a good one.

Trust sump extension.

Turbonetics GTK-850 turbo and big Turbonetics external gate

[ezy_09s]

What head gasket, MLS or copper ?...i have seen copper head gaskets needing a re-torque.

You shouldnt see this normally with a good mls though.

[[200]]

you can get ARP studs for ~$250 + what ever labour it takes to fit them.

not for the rb26 ones.

[tricstar]

What head gasket, MLS or copper ?...i have seen copper head gaskets needing a re-torque.

You shouldnt see this normally with a good mls though.

I'm not sure, I'll be ring the mechanic who built it tomorrow, I would think judging by the rest of the build, it would be a good one, doesn't appear to have skimped anywhere else..

[snozzle]

so the engine is leaking oil from the head gasket to the OUTside of the engine but the car is still running fine and not even mixing oil with water?

what

[Swiper the Fox]

The whole thing souds like a bit of a crock from the info you have provided.

Not from you personally but from the 'workshop'.

Stands out like dogs nuts...can't understand why the king of RB engineering ^ didn't pick it up instantly.

I build these engines all the time and i have a fair idea what has happened. Was it built locally?

Edited May 17, 2010 by Swiper the Fox

[tricstar]

The whole thing souds like a bit of a crock from the info you have provided.

Not from you personally but from the 'workshop'.

Stands out like dogs nuts...can't understand why the king of RB engineering ^ didn't pick it up instantly.

I build these engines all the time and i have a fair idea what has happened. Was it built locally?

it was built in adelaide , I'm in perth..

please elaborate on whats happened

[Swiper the Fox]

it was built in adelaide , I'm in perth..

please elaborate on whats happened

Ok..for a start there are NO oil feeds to the head on the exhaust side of the engine...so that statement they made to you is incorrect.

It was built using a fastner when correctly installed that can generate a maximum clamping force of 220,000psi under operating conditions below its yield strength.

The engine only saw 30psi of boost!...stretching a 12mm main stud takes a bit more than that.

My guess is one of these...incorrectly installed stud...probably bottomed out or incorrectly torqued , poorly cleaned head that has leaked oil onto the head gasket during installation compromising the seal or the block is split around the turbo oil feed.

[tricstar]

Ok..for a start there are NO oil feeds to the head on the exhaust side of the engine...so that statement they made to you is incorrect.

It was built using a fastner when correctly installed that can generate a maximum clamping force of 220,000psi under operating conditions below its yield strength.

The engine only saw 30psi of boost!...stretching a 12mm main stud takes a bit more than that.

My guess is one of these...incorrectly installed stud...probably bottomed out or incorrectly torqued , poorly cleaned head that has leaked oil onto the head gasket during installation compromising the seal or the block is split around the turbo oil feed.

thanks for your help..althou none of those options sound good ..

cheers

[Swiper the Fox]

thanks for your help..althou none of those options sound good ..

cheers

just something to compare...i knocked up an engine from mostly used parts for my wife so she had a decent engine to race at the drags. It had 2nd hand Nissan head bolts and stock head gasket...

It was thrashed for over 3 years and won about a dozen trophys and made 465+awkw at around 35psi of boost!

Id never recommend anyone ever actually do this but it goes to show it not the sum of the parts used...its how they are put together that really counts the most.

[tricstar]

just something to compare...i knocked up an engine from mostly used parts for my wife so she had a decent engine to race at the drags. It had 2nd hand Nissan head bolts and stock head gasket...

It was thrashed for over 3 years and won about a dozen trophys and made 465+awkw at around 35psi of boost!

Id never recommend anyone ever actually do this but it goes to show it not the sum of the parts used...its how they are put together that really counts the most.

boy aint that the truth