head bolt torque settings r5

Newbie Joined: 19 May 2005 Posts: 19

HELP!!!!!!
am desperately tring to find out what the high tensile head bolts for a r5 gt turbo engine should be set at on their torque settings!
haynes manual is useless for uprated bolts... damn thing
all tuning sites are equally useless
someone rescue my engine rebuild!!!! Exclamation

Newbie Joined: 19 May 2005 Posts: 19

oh yeah and what do uprated bolts look like, am not sure if i already have them or not... i have two sets, one has 1.2 written on them and the other set has 1.1
any help welcome

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

fit standard bolts just make sure they are torqued properly.

Uprated bolts the cause of many an engine failure. Look at the K series!

Also the 1.1 and 1.2 I assume its stamped on the head? Thats the bolts tensile strength and 1.1 is garden fence stuff high tensile stuff is 8.8 up

Newbie Joined: 19 May 2005 Posts: 19

yeah is stamped on head,

but why do uprated bolts cause engine failures? arent they supposed to be an improvement?

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

do u think ur std bolts are gunna snap?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

well my good man. lets look at a humble head bolt.

They are stretch bolts, this means when you tighten them up they are preloaded a certain amount so their elastic limit isn't exceded.

That means they 'move' with the head and block as it heats up.

This ensures a long happy life together.

This is only applicable to stock bolts, you know where ther manufacturer has developed the bolts for the engine.

GFo get some high tensile bolts and they may be strong but the engine and headgasket isn;t goign to like the fact its all gonna move differently. It can pull threads etc.

To loose not enough preload in the bolt means the head can 'float' about which grooves the head face thus allowing it to pop.

The only worthwhile upgrade is to head studs, this clamps the head more evenly than you can with a bolt.

Head gaskets don't just blow theres a reason, if its not overheated and the bolts have been fitted properly the only thing that will blow a gasket is detonation.

Rover K series, these apparently blow head gaskets left right and centre, they do when they are not built properly. 1 major cause of their problems aside from plastic dowels is the use of non rover head bolts, they are 'uprated' they don't stretch the same way and thus bugger things up.

Renault rally cars survived just fine with renault headbolts.

Newbie Joined: 19 May 2005 Posts: 19

yes i see, that makes a lot of sense when you break it down like that. thankyou v. much.

and where can i find head studs?

I will crack on with getting the head re-skimmed, group A`head gasket and hopfully some head studs

I have just managed to fit a vauxhall calibra 2.0 turbo radiator into the
r5.
it cost 15 quid down the scrappie i thought y not?

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

that seems like a very sensible mod, why not indeed!

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

arp will do suitable studs.

Newbie Joined: 19 May 2005 Posts: 19

thanks, will look it up, you guys are cool!

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

we try our best