11mm To 12mm Head Stud Rb25 Block Rb26 Head

[ijoshi]

hey

can i drill and tap the rb25 block to 12mm to suit a rb26 head myself?

or would it be best left to the pros, also where in sydney and how much?

also would i be able to use the standard rb26 ecu and loom.......rb26 head on rb25 bottom end

cheers, josh

[R31Nismoid]

I've gotta ask... whats the motivation for this?

You have VCT with the 25 head. Get an adaptor made to get the ITB's if that is what you are after, otherwise a RB25 head even stock innards holds 350rwkw without a drama, plenty of people dont that now on stock head gear.

Failing that i would be going a NEO head, not a RB26 one.

[The Dan]

I've gotta ask... whats the motivation for this?

You have VCT with the 25 head. Get an adaptor made to get the ITB's if that is what you are after, otherwise a RB25 head even stock innards holds 350rwkw without a drama, plenty of people dont that now on stock head gear.

Failing that i would be going a NEO head, not a RB26 one.

+1

And drilling the block is not such a good idea. I now there are people who will say 'but I've done it and never had an issue' but it does weaken the block and is not completely necessary.

You can just use the 25 studs but it is advised to have ARP washers with a larger OD to suit the head.

[R.I.P.S NZ]

Normal RB25 11mm ARP head studs, don't bother messing with the block, its totally un neccessary even if you want to use a 26 head.

Rob

[GT-RZ]

Aftermarket 11mm Head studs have a higher clamping force and UTS than that of the factory 12mm head bolts.

Like said earlier the best option is to fit some sleeves over the studs to support the head correctly.

[R.I.P.S NZ]

The head is located with the 2 dowels, no need for sleeves over the 11mm studs.

[ijoshi]

hey

thanks for the info

i am using a rb26 head because its all i got of the rb26 motor

i just happen to have a rb25 bottom end lying around

cheers, josh

[R.I.P.S NZ]

A 26 head won't go straight onto a R33 RB25 block but it will on a R32 RB25 so check it all out properly before you get carried away.

Rob

[ijoshi]

what needs to be done? i might scrap the rb25 idea

will it go straight on the rb30 block? s2, i have a rb30 lying around as well, i need the car to pass a blue slip not sure if rb30 engine capacity is allowed for r33 gtst

i am thinking of rb25de pistons ceramic coated rb30 standard bottom end

then all i need is a ecu for it

[R31Nismoid]

If your going to waste time with DE pistsons, rebuilds etc just to make use of a 26 head...

I suggest this as a much faster and more efficient alternative, no legalities, no worries and so on...

1. Sell RB26 head.

2. Buy complete RB25

3. Install

Should work out around the same by the time you throw money about putting DE pistons in and so on for a cheap rebuild... you get an entire package ready to go.

If you also then have turbos and stuff lying around (to put on), then you sell off the RB25DET turbo gear and install your own.