ive done a search on this and all ive fould is that the oil and water galarys line up but you have to modify the bolt holes. what do you have to do to the head bolt holes ????? and has anybody used these spool import conrods????

i wanna know same question with da rods

drill the block and tap the right size thread into it

would it be better if i went the 26 head apposed to the 25

25 head uses the same thread as rb30. you use standard rb25 bolts. on the other hand you need to modify the head a little bit.

Does the GTR head flow more? It runs solid lifters doesnt it? Does this allow for more cam choices? A mate makes 240rwkw on his stocker GTR motor with more boost and powerFC. Its not so easy to give him **** about owning a slow skyline anymore.

could i just use the rb25 head bolts instead of the 26 head bolts to put the 26 head on.

no.

thats cool ill just get the bolt holes done when i get the block o-ringed cheers for the help.

Quote: Originally Posted by DeVL could i just use the rb25 head bolts instead of the 26 head bolts to put the 26 head on. Yes. Its only 1mm difference diameter and the bolts don't locate the head so it makes no difference. Not the IDEAL way to do it but considering what most people's VLs are like it will not be the worst thing on the car.

true dat. case in point, my car.

it would be seriously foolish to do that,for the sake of tapping a few threads

Quote: Originally Posted by duz360 it would be seriously foolish to do that,for the sake of tapping a few threads Not seriously foolish at all- just not perfect. And its not a case of tapping a few threads. Its 2 drills and a tap and not to mention a TOTAL strip of the motor which some people don't always want to do or have overlooked durign the build and its already together. The difference in operation of the motor would be zero unless you were looking at around 600hp or something silly like that.

considering that someone is building a rb26/30 its a given that they will want big hp. if you have overlooked this and built the bottom end just turn the engine upside down to drill and tap the threads.

haha! I hope you aren't serious. If anyone is thinking of doing this the block MUST be secured on a flat surface which is perpendicular in both planes to the chuck. It must be drilled and tapped this way. If you can do that upside down- good luck. And no not everyone builds a 30/26 for big HP. Some people have sensible goals and want good streetable torque.

ok lukevl i give up with you

Quote: Originally Posted by Dansedgli Does the GTR head flow more? It runs solid lifters doesnt it? Does this allow for more cam choices? A mate makes 240rwkw on his stocker GTR motor with more boost and powerFC. Its not so easy to give him **** about owning a slow skyline anymore. It will be more dodgy to have threads not taped correctly and perfectly square, then 1mm undersize bolts in my books. Few advantages of the Rb26 head would be, that you get solid lifters, great inlet manifold with individual throttle bodies, sodium filled exhaust valves and a huge camshaft choice and no n-vct to contend with. The head itself (cams aside) will not flow more then the RB25 though, same valve and port sizes basically.

Quote: Originally Posted by RB30-POWER It will be more dodgy to have threads not taped correctly and perfectly square, then 1mm undersize bolts in my books. Few advantages of the Rb26 head would be, that you get solid lifters, great inlet manifold with individual throttle bodies, sodium filled exhaust valves and a huge camshaft choice and no n-vct to contend with. The head itself (cams aside) will not flow more then the RB25 though, same valve and port sizes basically. No way. What happens when your motor is together and the bolts either pull out or have tight spots when they are being torqued up? Blown head gaskets and you're scratching your head. Do you know what 0.5mm per side is- stuff all. If I gave you an Rb26 head and Rb25 bolts and told you to put it together you wouldn't even notice it when you screwed it down. And an Rb26 will make more power than an Rb25 because it is a genuine high-port head derived from racing whereas the 25 was made just for street and has a worse short turn. The 26 flows more and it has just about the same size ports. Oh and bigger valves

Quote: Originally Posted by LukeVL No way. What happens when your motor is together and the bolts either pull out or have tight spots when they are being torqued up? Blown head gaskets and you're scratching your head. Do you know what 0.5mm per side is- stuff all. If I gave you an Rb26 head and Rb25 bolts and told you to put it together you wouldn't even notice it when you screwed it down. Sorry you lost me, To clarify what i said, i would prefer the standard RB25 bolts used with the RB26 head and standard RB30 block threads, then some dodgy guy drilling and tapping the larger hole in the RB30 block by hand and it not being perfectly vertical with the deck. You don't want head bolts pulling down on an angle at all. To bring another question to the table, can you get some jig or machine shop to tap the threads perfectly, because i wouldn't want to do it by hand?

my dad has some form of jig (though it wouldnt be idealfor tapping a block due to its size) , but it has a carrier with 3 legs that sits perpendicular to the surface being tapped , the tap and handle mounts in the carrier as a one peice assembly. he is a fitter and turner by trade and this thing is about 40 years old