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Rb25/30 Build Help

Dylan andrew
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Dylan andrew Apprentice

Dylan andrew

Posted
Posted

Hi all,

So at the moment i am currently building my first 25/30, really my first engine and i'm needing some advice.

i have gone with cp pistons, Manley rods, i will be running gtr n1 oil pump fitted with oil collar. with a cometic head gasket, all arp studs and acl king bearings.

compression is sitting low 8 cant remember exact 8.1. head is rb25det as well

so my question would be, what oil restrictors are people running?if any at all? needing to know this asap

and i'm also looking at changing valve springs and maybe cams, im wanting to keep the hydraulic lifters, unless someone can convince me otherwise.

what cams and valve springs should i run or could i just run standard cams and different valve springs with higher seat pressure?

overall looking to get anywhere from 500-650 hp

Thanks :rolleyes:

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The Mafia Grand Master

The Mafia

Posted
Posted

I ran 2 x 1.3mm restrictors in mine.

I still had VCT and did the internal mod so I was robbing oil from the lifters to run it.

Not sure how effective that was because when the VCT is on, it is shut and holding pressure on the cam pulley so that it can advance. When it de-activates, it opens up and releases the pressure which means it is flowing and adding to the amount of oil in the head ( I'm not 100% sure because I don't have a head here to inspect and I'm not sure if the VCT had it's own drain. I am pretty sure it uses the head drains)

Anyway, If I did it again I would look at using 1.2mm feeds. EVen they seem to be big enough from what I have heard.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

You need more compression...9:1 or better. I used 2 x 1.0mm restrictors.Depending on the head you are using you may benefit from some higher lift cams without excessive overlap (a custom grind) and retaining VCT. Read the latter part of the oil control thread re venting your sump.

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