Hi All,

I am having some issues with my head lifting at high boost, or at prolonged running (top speed) at slightly off peak boost. i am currently running stock sized ARP head bolts but it looks like they might not be enough.

My question is, and im just seeking confirmation of this, that the block/head would need machining to accept the larger 1/2" ARP studs/bolts?

If so then i wont do it as i dont want to take the engine out fully again, if they dropped right in then i would do it of course. Having never seen any though i would be assuming that the threads are different on then, hence the need for machining.

If anyone that has then in their engine can advise that would be great.

 

What is your power output?

You would need to have the block machined.

 

692 on a conservative dyno Rich. (of your finest british bhp of course)

In truth the head lifting was not something that i had initially thought i would have to deal with in the build, but as its now making great power these things rear their head....As its just a drag car then it looks like i might just have to live with it and keep it in check.

 

Look into these http://www.a1technologies.com/index_flash.php. Also did you treat the head gasket with copper spray.?

Who sleeved the block.? Are you running any sort of wire around the sleeves?

 

The block was sleeved at knight engines in northampton, they do/did a lot of work for prodrive etc, seem like they did a good job though.

Ill take a look at the link.

The tops of the sleeves i did grease to help sealing, when assembling. When you say treat the HG with copper spray do you mean a light dusting from about 30cm type of thing? I have some so i can certainly try that.

Sorry but what do you mean by wire around the sleeves?

 

I've never heard of anyone greasing either the hg or the surfaces. From my knowledge there both suppose to be oil and grease free.? (I could be wrong)

Yeah that's what i mean with the copper spray. You want a nice even coat.

Check this link out. http://www.goldeneaglemfg.com/index....id=3&chapter=0 You need to click on block o ringing.

 

Rich is spot on, O-ringing the sleeves will benefit you in youre application. I Had mine oringed for added insurance. Basically they cut out a grove on the top of each sleeve. Hondas seems to go with the copper wire. This wire sticks out prob .003" or so and when the head is torqued down the wire provides a better bite into the gasket creating a better seal. There is also the option of using Stainless Wire, However with stainless wire you need to have a reciever grove cut into the head (alot of times copper headgaskets are used with that set-up, but not always) Copper is able to crush which is why a reciever groove is not needed with copper wire.

I also would Highly advise against any greasing of the sleeves, that could be youre problem right there....Should be a perfect Clean, Flat surface for the headgasket to seal correctly. With the exception of copper spray. O-ringing would require the block to come out of the car. So dont think youll go that route. Next HG change go OEM with copper spray. ARP studs you have on now should be fine for youre power level

 

I believe you'd pull the threads out of the aluminum block before you'd ever stretch the ARP head studs. What are you torquing them down to?

 

isnt that the same thing as wills rings? i dont have those grooves anyway!!!

Im not sure that would stop the head lifting though would it?

Maybe the ARPs can be torqued down a little higher than stock to help counteract it anyway.

 

80lbft whichi believe ARP specify. Assuming my torque wrench is in spec of course! it was done last year.

 

The whole idea of the o ring is to help prevent the hot gasses escaping under high cylinder pressures. It most likely would cure what your experiencing. Consider it as a last resort though as your this far now.

Have you re torqued the head studs or not?

 

no i havent, the heads coming off at the moment anyway to replace the HG irrespective, so i will be retorquing them down after that of course.

It may just be that they had let go of a little of their grip.

 

Sweet, make sure the surfaces are spotless. I'd be tempted in a set of new studs if it was my engine.

 

may wanna recheck the tune if you're lifting the head.