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Rb25Det Forged Pistons

t304vkcalais

By t304vkcalais,
in Engines & Forced Induction

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t304vkcalais Enthusiast

t304vkcalais

Posted
  • Author
Posted

been looking at cp alot,and want to have that little more displacment but yer depends on what the bores look like, head was serviced less then 8000km ago, thinking bout throwing some springs and a high lift cam in to get more mid range/top end. but once again depends on condition of valves etc to see how far i go there.

Dasmbo Collaborator

Dasmbo

Posted
Posted

I have done something similar i used CP +40 8.5.1 comp pistons and Manley con rods arp2000 bolt set and found no problems with them. All RB25DET engines have block mounted oil squirters.CP pistons dont interfere with them

when getting your motor bored you also might want to get the block decked crank tunnels honed and final hone in yor bores done with a torque plate

I would recomend at least replaceing the valve springs with new standard ones and get the head decked as i think the pistons from usa are slightly lower comp and get the valve seats done

I was told that i would lose performance and later turbo spooling beause of the lower comp pistons but i had the head and block decked and fitted a greddy manifold and got rid of about 4 feet of turbo pipe work

and found if anything turbo spools faster{hi-flow}.

well just got a heap of detonation on my 25 and have decided to pull the motor down and rebuild it.......again, the only things im going to need to change will be pistons,headgaskeet and new bearings.

i have done the n1 pump,oil pump drive gear,oil restrictors,26 rods,arp studs everywhere blah blah blah.

chasing 400hp and i know a standard 25 will do it but im wanting a bit of safety so decided of forged pistons and cometic headgasket, what brand pistons are doing well in 25's at the moment and what ones to stay away from, going to be boring it out 40 thou aswell.

tim

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

That is correct, springs not valves, the thing is tho how much does it cost? The engine is out and head is off if it is not that expensive may as well do it for piece of mind

Yes the head is off... Realistically though it does not need touching at all.

It's just a case of sort the bottom end, bolt the head back on, away you go.

JustinP Mentor

JustinP

Posted
Posted

I have 9.0 compression CP pistons. They can do custom jobs but they cost more as they are not off the shelf.

Pity they are only 8.5 compression, I would be interested in 9-9.5. My car only runs E85 so I would look at ~9.5.

t304vkcalais Enthusiast

t304vkcalais

Posted
  • Author
Posted

i got another head sitting here that i can get somework done on and allways bolt it up later, kind of interested in doing a oil drain from the head aswell while its out.mayby a decent set of springs and get some sure cams for it as well with about 9mm lift

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

You don't need an external drain if you put proper sized restrictors in that match against the oil flow you will have.

It's funny people haven't needed them at all really before, and the last 18 months they are the latest rage... And are basically a band-aid type solution.

  • 3 weeks later...
Jimz Enthusiast

Jimz

Posted
Posted

25s don't have squirters

Hey buddy, sorry to burst your bubble, but the RB25DET does have oil squirters. They are in the bore and are used for lubrication and for crown cooling.

By the way, I would have gone with JE Pro Series Pistons if you had the dosh. I am using them in my current rebuild as they come standard with Nitrite coated rings and tool steel gugeon pins. I chose Manley H-Beam rods with ARP 2000 rod bolts.

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