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Comman Problems With Rb25det

old mate

By old mate,
in Engines & Forced Induction

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old mate Collaborator

old mate

Posted
Posted

i did a search and went back to about mid 07 and thought no point going further back due to development. or i typed the wrong shit in.

any ways i have an rb25det s1 pulled down and it will be rebuilt with pistons and rods, bearings, studs, gaskets of major brands. the motor will see drift work plus track/grip. is there anything i should spend my money on to avoid say oil problems or somthing simialr which is easy to fix but can cause big problems if i dont.

any help you can give would be great.

cheers, steve.

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The Mafia Grand Master

The Mafia

Posted
Posted

there is a massive thread based on the oiling problems that plague the RB25.

I'd find it and do everything that it suggests, because most of the problems arise when doing track work, in high revs.

The Mafia Grand Master

The Mafia

Posted
Posted (edited)
Dry sump will fix everything :P

But upgrade the oil pump

Good catch can and breather setup

Maybe head to sump oil drain

500mls extra oil.

dude, putting a bigger oil pump on, and not doing the rear head drain, or blocking the rear oil feed in the head makes the problem worse.

The whole problem is oil pooling in the head do to bad drainage at high RPM. If you put a bigger oil pump on, it will simply pump more up there and into the catch can, creating a disaster. I've seen this happen - GTR oil pump on a RB25 with no extra drains... or the rear feed blocked. Blew most of the oil into the catch can.. and then when the sump was starved... bang.

You're giving bad advice I'm afraid...

Edited by The Mafia
MBS206 Grand Master

MBS206

Posted
Posted
dude, putting a bigger oil pump on, and not doing the rear head drain, or blocking the rear oil feed in the head makes the problem worse.

The whole problem is oil pooling in the head do to bad drainage at high RPM. If you put a bigger oil pump on, it will simply pump more up there and into the catch can, creating a disaster. I've seen this happen - GTR oil pump on a RB25 with no extra drains... or the rear feed blocked. Blew most of the oil into the catch can.. and then when the sump was starved... bang.

You're giving bad advice I'm afraid...

The advice I've been given by most engine builders is not to restrict the oil getting up top. It's all in freeing up getting it back down to the sump.

IE, you REALLY want a good drain setup to get it out of the head. Then, you're all sweet.

The issue is only at high RPM, so who knows what it's doing when you're blocking an oil feed off and sticking to low RPMs. You might be starving the head of oil slightly.

MBS206 Grand Master

MBS206

Posted
Posted
I did see a drain set-up for RB30 heads on ebay, was simply a fitting tapped into the rear of the head for extra drainage. Would thios also work on an RB25?

I'm just using the fitting that TUF_RX3 from here made, which is press fitting into the back of the head.

Others drill and tap a fitting in.

The Mafia Grand Master

The Mafia

Posted
Posted
The advice I've been given by most engine builders is not to restrict the oil getting up top. It's all in freeing up getting it back down to the sump.

IE, you REALLY want a good drain setup to get it out of the head. Then, you're all sweet.

The issue is only at high RPM, so who knows what it's doing when you're blocking an oil feed off and sticking to low RPMs. You might be starving the head of oil slightly.

Well, the GTR have a blocked feed from the factory, and a restricted feed up the front. So less again.

I'm pretty sure SK has said that even with a blocked feed at the back, there is still more than enough oil for the hydraulic lifters in the RB25.

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