Austarion

hi guys, i'm having some problems with my head bolts. originally i was going to use some 12mm head studs, but they dont fit through the evo head. so i scrapped that idea and decided to go back to the starion head bolts which seem to go through, despite being 12mm also

but now the starion bolts wont bed down properly, i can feel them binding up but theyre still 10mm or so above the washer. what the hell is going on?

i've stopped for now. stuck working outside and it wont stop bloody raining.

yeah thats right im building my dohc headed engine outside.

you will need to machine evo head to talke 12mm bolts and use VR4 ones

yeah thats the conclusion i had come to :? bugger is the 11mm thing an evo only trait? never seen it mentioned in anyones elses build threads

plasticdash wrote:you will need to machine evo head to talke 12mm bolts and use VR4 ones

I remember reading somewhere that one of the stud holes is an oil feed into the head so you may want to check this out as it almost certainly need to be drilled a bit larger than the stud to accomodate the oil feed
I am sure that there will be someone out there that can confirm if this is so

i dont understand how it could be both a bolt hole and an oil drain.. if there was enough room for it to be a meaningful oil drain, the bolt fit would be really sloppy.. i'll look it up, but i'd be surprised if there arent dedicated oil drains

I just used vr4 head bolts then studs, went straight in.

vr4 bolts went through your evo head?

stariontron wrote:i dont understand how it could be both a bolt hole and an oil drain.. if there was enough room for it to be a meaningful oil drain, the bolt fit would be really sloppy.. i'll look it up, but i'd be surprised if there arent dedicated oil drains

Not a DRAIN, a FEED!

yea def need to take the evo head out to 12mm to fit on to a vr4 block

stariontron wrote:vr4 bolts went through your evo head?

no, VR4 bolts went through the VR4 head

yeah as above, you need to drill out the holes on the evo head to 12mm to run the VR-4 head bolts (which are shorter than the SOHC bolts).

sweet as. any more news on this bolt hole/oil feed that old fart was talking about?

Give Geoff Fear at SSS Automotive in Sydney a call - he knows all about the oil feed / stud problem. He fixed an EVO head that blew 3 turbos through oil starvation due to this issue.

An alternative is, just put the studs in, then check your oil pressure to the turbo before relying on it. If it's down or cut altogether, you can just get your oil feed from elsewhere (mine comes from down on the oil pump).

i was planning on using my factory starion oil feed. that comes out of the block somewhere. that mean im not going to run into any problems?

Yep, if you're not using the oil feed from the head, then you'll have no dramas with the larger studs.

Seems like a safer way to go after speaking to people that have experienced oil issues from the studs.