Thread: Head bolts - what now?

Originally Posted by discorevy

Geez, BennehBoy, cheers for that info , don't think I'll be fitting those , what was the reasoning for fitting and was it T&K precision who calculated 70 ft lb for the final setting ?.( personally don't think this is enough if your running a big map / big boost ) , is that an Allisport manifold ?, I'd be replacing all the manifold studs as it's only a matter of time before others will snap. My opinion only

Well, here's the thing, T&K 'just make them to spec', they don't know what the torque values should be.

I inquired exhaustively in the UK and hit a brick wall of either ignorance or reluctance to supply any torque settings. I've gone with what's least likely to strip the block threads based upon a considered best estimate looking at ARP values for similar stud lengths and most importantly numbers.

The idea was to see how I get on and increment in 10lb feet if I see signs of HG failure/bypassing.

So far all is well, and I've ragged it quite hard. The map which is on is AFR based and is chucking in 85mg of fuel, so it's quite hefty.

Vehicle has a hybrid turbo (billet chra), turbosmart actuator, providing ~25psi of boost, allisport manifold (brilliant bit of kit), allisport full length intercooler, 3 BAR MAP, Solid flywheel with uprated clutch and plate, full stainless semi straight through exhaust, and a Provent.

PS Reasoning for fitting was simply 'because I can' - I bought them before I switched to the AFR remap, the previous injection timing map was creating far more boost due to the fuel being chucked in behind the receding pistons and created unnecessary exhaust, heat, and stress on the haed/gasket.

Originally Posted by discorevy

Geez, BennehBoy, cheers for that info , don't think I'll be fitting those , what was the reasoning for fitting and was it T&K precision who calculated 70 ft lb for the final setting ?.( personally don't think this is enough if your running a big map / big boost ) , is that an Allisport manifold ?, I'd be replacing all the manifold studs as it's only a matter of time before others will snap. My opinion only

So I've upped the torque to 90lb ft, had some exhaust gas in the cooling system after thrashing it - not happening after increasing the torque. I had deliberately kept the initial setup conservative with the intention of nipping it up progressively anyway.

Originally Posted by BennehBoy

So I've upped the torque to 90lb ft, had some exhaust gas in the cooling system after thrashing it - not happening after increasing the torque. I had deliberately kept the initial setup conservative with the intention of nipping it up progressively anyway.

I hope its not a case of shutting the gate after the torque's have bolted ........or something like that

Nah, all seems good now. I knew it might be a voyage of 'discovery' so have a spare HG just in case.