Neil S

iTrader: (1)

After the carry on I've had with cam cap studs pulling out of my head I've started thinking...

I'm wary of any more pulling out and am not 100% confident that the studs will take a 20Nm torque.

I was wondering if it's acceptable to use an all-steel self locking nut on them (the same kind as found on the exhaust manifold). This would hopefully let me use a slightly lower torque setting without fear of coming loose.

Any thoughts on this from the PF experts?

Neil.

Dangerous Malcolm..

Is there enough thread for two nuts?

-beefy-

iTrader: (6)

i cant see a reason why not neil , but im no expert ,

why do you think theyre going to pull the threads mate

you have any issues removing them >

beef

RWD_cossie_wil

iTrader: (9)

If the studs are pulling out of the head, better nuts won't help. You need to get the head helicoiled to retain the cam studs better .

Neil S

iTrader: (1)

I've already helicoiled 4 or 5 of them in the past, i'm worried about these pulling out too! Self locking nuts would surely allow lower torque with lower risk of coming loose?

I just think the head is geting very soft on the exhaust side Beef...

Dicko&Vacant

iTrader: (3)

neil i had 4 pull out on my last cossie and it snapped the exhaust cam in the process lol

got them helicoiled and was fine so cant see why yours wont last

tracktoy

the exhaust manifold nuts are called 'philidas' nuts

http://www.philidasfasteners.co.uk/products.html

not the cheapest but they do seem to work quite well

Neil S

iTrader: (1)

Yep, just bought a load for the fannymould

jpfour

just a thought but when was your torque wrench last (if ever?) calibrated?
could be that its over-torquing the fasteners resulting in stripped threads
even if its new it may have been incorrectly manufactured.

-James-

tabetha

philidas is the name of the firm not the type of nut, these(turbo) nuts are commonly reffered to as K NUTS, although a true K nut they aren't, as very slightly different construction, mainly used in aero industry where everything is a rip off.
In case you haven't spotted the problem with a locking nut, it will not come undone because it grips the stud, but it also gives a false reading to tightness as some of that tightness is going to be the nut itself rather than how hard the cap is clamped.
If the head is ok the std studs are perfectly fine at the correct torque.
You can make the locking nuts free by just squeezing in a vice a std nut, just till it has a very slight oval to the hole, does the same job, bit of trial and error till you find how much to squeeze them but easy to do.
tabetha

polly_x

iTrader: (2)

Is that a joke?

Squashing nuts in a vice to turn them into locking nuts to then use in your expensive engine and hope you squashed them just right? Seriously that cannot be good advice?

Neil, my way of doing this would be to get it right in the first place and ensure the studs are correctly fitted in the head and then use the correct nuts torqued to the correct setting. If the head is so soft that it wont take and hold a helicoil then consider a different head mate.

Personally I would use time serts not helicoils too. Expensive but peace of mind.