Jump to content
SAU Community

Recommended Posts

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.

Link to comment
https://www.sau.com.au/forums/topic/249968-comman-problems-with-rb25det/
Share on other sites

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.

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
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.

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 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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • If you are keeping the current calipers you need to keep the current disc as the spacing of the caliper determines the disc diameter. Have you trial fitted the GTS brakes fit on a GTSt hub or is this forward planning? There could be differences in caliper mount spacing, backing plate and even hub shape that could cause an issue.
    • Hi there I have a r33 gts with 4 stud small brakes, I'm going to convert to 5 stud but keep the small brakes, what size rotor would I need?
    • First up, I wouldn't use PID straight up for boost control. There's also other control techniques that can be implemented. And as I said, and you keep missing the point. It's not the ONE thing, it's the wrapping it up together with everything else in the one system that starts to unravel the problem. It's why there are people who can work in a certain field as a generalist, IE a IT person, and then there are specialists. IE, an SQL database specialist. Sure the IT person can build and run a database, and it'll work, however theyll likely never be as good as a specialist.   So, as said, it's not as simple as you're thinking. And yes, there's a limit to the number of everything's in MCUs, and they run out far to freaking fast when you're designing a complex system, which means you have to make compromises. Add to that, you'll have a limited team working on it, so fixing / tweaking some features means some features are a higher priority than others. Add to that, someone might fix a problem around a certain unrelated feature, and that change due to other complexities in the system design, can now cause a new, unforseen bug in something else.   The whole thing is, as said, sometimes split systems can work as good, and if not better. Plus when there's no need to spend $4k on an all in one solution, to meet the needs of a $200 system, maybe don't just spout off things others have said / you've read. There's a lot of misinformation on the internet, including in translated service manuals, and data sheets. Going and doing, so that you know, is better than stating something you read. Stating something that has been read, is about as useful as an engineering graduate, as all they know is what they've read. And trust me, nearly every engineering graduate is useless in the real world. And add to that, if you don't know this stuff, and just have an opinion, maybe accept what people with experience are telling you as information, and don't keep reciting the exact same thing over and over in response.
    • How complicated is PID boost control? To me it really doesn't seem that difficult. I'm not disputing the core assertion (specialization can be better than general purpose solutions), I'm just saying we're 30+ years removed from the days when transistor budgets were in the thousands and we had to hem and haw about whether there's enough ECC DRAM or enough clock cycles or the interrupt handler can respond fast enough to handle another task. I really struggle to see how a Greddy Profec or an HKS EVC7 or whatever else is somehow a far superior solution to what you get in a Haltech Nexus/Elite ECU. I don't see OEMs spending time on dedicated boost control modules in any car I've ever touched. Is there value to separating out a motor controller or engine controller vs an infotainment module? Of course, those are two completely different tasks with highly divergent requirements. The reason why I cite data sheets, service manuals, etc is because as you have clearly suggested I don't know what I'm doing, can't learn how to do anything correctly, and have never actually done anything myself. So when I do offer advice to people I like to use sources that are not just based off of taking my word for it and can be independently verified by others so it's not just my misinterpretation of a primary source.
    • That's awesome, well done! Love all these older Datsun / Nissans so rare now
×
×
  • Create New...