RB25 Rebuild plan: please evaluate/ fill in gaps

[accel junky]

Please evaluate my series 1 rb25 rebuild plan and help me fill in the gaps as well.

I lost 3 cylinders after tuning. Got 40,90,60 compression on them... going to have the motor rebuilt here in the US.

I have searched thoroughly on the site but I'm still in the fog about some things:

RB25 Buildup Plan:

-Bottom End:

Metal Headgasket: what mm thickness?

ARP Head Studs: Same as SR Main Studs?

Wiseco RB26 Pistons 86.5mm Comp=8.8:1 or CP Pistons 8.5:1

Pauter RB26 Rods: .827” Pin Dia

Rod Bearings:?

Main Bearings: ?

-Maintenance

OEM Waterpump or N1 Waterpump ?

Power Enterprise Timing Belt (or Greddy or whoever)

Nismo Thermostat

ARP Exhaust Manifold Stud Set

OEM Full Gasket Kit (already have)

Fyi: Motor will be handling 400-500whp

Thanks a ton!!! ,

Daniel

[Bass Junky]

N1 Waterpump only required if you are going to spend a lot of time at high rpm.

Timing belt, all the same anyway.

[R31Nismoid]

ok.

I'd use Arias pistons...

GTR Rods

N1 water pump

stock head gasket

there are my blanks

[Trust33]

R31 nismoid,would the stockie head gasket be enuf for 400-500rwhp.reliably speaking?

If you are hitting the tracks things like oil coolers come in handy.it's a reliability thing.

If you go r31nismoid's way for a rebuild,and it is reliable for that type of hp,then,you wont need forged rods,and you could spend it in other places like a set of cams etc.

[Al]

Also need a N1 oil pump.

I too would stick with a factory head gasket, i have seen a RB25 pull over 330rwkw on a conservative dyno with forged pistons, a preped bottom end and stock gasket. Two year running without a problem and still going.

Get new stock bearings, the N1 oil pump will ensure there is enough oil to lubricate them.

[Clint32]

Use a metal headgasket, the thickness will depend on the pistons and head cc's so you can decide that once bottom end together.

If you use rb26 pistions you need the rb26 crank as well as it has 2mm more stroke therfor the pin height on the pistions is different. SO just get pistons for rb25 and i would say 8.5:1 comp.

I believe ARP have just relased head studs for rb25 head, pretty sure sr is diff as they have been avliable for a while and we couldnt use them then.

RB26 rods are good for around 450rwhp with some rod bolts and prep work, but in the us for the cost any forged rb26 rod will do the job.

Use std nissan bearings, along with N1 water and oil pumps

If your using a rb25 head at 500 rwhp you will need cams, and springs deffiantely, and i would also add valves and solid lifters to the list if you wont a safe reliable motor, at 400rwhp should all be good std, but 500 very unlikely in my opinion

[accel junky]

So, what about piston size? 86.5mm is the size that www.phase2motortrend.com lists for CP Pistons for the RB25.

And it IS ok to get the Pauter forged rods designed for the Rb26? www.pauter.com/nissan.htm

And std nissan bearings will do? Do I just order a set for main and rod in general? Or does my engine builder need to measure anything first?

I'm thinking about going with a stock height metal headgasket, such as 1mm or 1.1mm any thoughts?

I've contacted RIPS about their Rb30 blocks to see the price, to see if it is worth it to go that route.

Thanks for the help!!

Daniel

[Clint32]

86.5 or even 87mm pistions are good for a little extra capacity

Any rods for rb26 will fit rb25

get the crank and rods measured before ordering the bearings nissan had different sizes