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Hello , so I have some scrambled thoughts on my planned setup for my rb25 build. 

Plan on using it for street/track mainly consisting of drifting. Plan on achieving 350whp.

refreshing the engine up as we speak. I have bought almost all the oil control issue mods ; bigger capacity sump from Lewis engines, n1 oil pump with billet spool gears to go along with it, head drain , oil restrictors, and nitto crank collar. Sound good ?

plus all the other maintenance bits.

performance side I’ll be getting a sinco exhaust manifold ,  unsure of turbo yet. Sard top feed 850cc injectors , walbro fuel pump, Hks fuel rail.

Since I’m not chasing for huge power and just wanting to keep my rb as reliable as I can I thought addressing all the oil problems with as much as I could. What else should I look at for ?

 

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If you still have the engine out put a couple of fittings in the sump so that you can connect directly to a catch can (one line to the top and one to the bottom for oil to drain back) as you may have problems if you spend a lot of time at WOT - especially when drifting.  get some modern injectors. A good ECU well tuned is key for reliability.

BTW if you haven't already fitted the "head drain" don't bother.

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1 hour ago, KiwiRS4T said:

If you still have the engine out put a couple of fittings in the sump so that you can connect directly to a catch can (one line to the top and one to the bottom for oil to drain back) as you may have problems if you spend a lot of time at WOT - especially when drifting.  get some modern injectors. A good ECU well tuned is key for reliability.

BTW if you haven't already fitted the "head drain" don't bother.

still have engine out and haven’t even begun to take it apart yet. Since it already has one fitting on the sump is it necessary to make another one ? Your saying to not bother with a head drain , is it not as efficient as everyone claims ? Or does it drain back better when fitted to the oil catch Can? 

Forgot to mention my ecu , I have a haltech pro plug in. So in that department im set 

Edited by Frozengrip

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I think you'll find there are no great claims for the head drain and there is no evidence that it does anything at all. If you have the correct oil restrictors oil will not pool in the head anyway.  A catch can vented to the turbo intake will create some negative pressure which will relieve pressure in the crank area and at full revs oil can accumulate in the catch can so a drain back to the sump will allow it to flow back when you lift off. If you put the fittings in the sump (above the oil level of course) which is a simple job when the motor is out then you can plug them and only use them if you find it necessary.

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The head drain probably only has benefit to fast drag cars. Otherwise it is only extra open area to permit air flow up from the sump into the top covers. And that's what the extra fittings into the sump do also (if plumbed to the top of the engine via a catch can).

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Head drain is good if your going to hit the track of give it death around the streets, people mock it but haven’t seen what they fix. If your motor is coming out I would bang one in there for peace of mind

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3 hours ago, WR33KD said:

Head drain is good if your going to hit the track of give it death around the streets, people mock it but haven’t seen what they fix. If your motor is coming out I would bang one in there for peace of mind

No one has seen what they fix. Rips stopped using them years ago.

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No one has seen what they fix. Rips stopped using them years ago.



Funny that we dropped a motor off there today and he asked what it was going to be used for and we told him and he wanted to install one so must be super old news about them.

Also guess 80% of people haven’t put there car hard around a track and see how much oil gets dumped in to the catch can

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2 hours ago, WR33KD said:

Also guess 80% of people haven’t put there car hard around a track and see how much oil gets dumped in to the catch can

have you even read the oil control thread?

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have you even read the oil control thread?


So what there saying if I take my head drain off and my engine starves of oil they will be rebuild it for me.

Also say that RIPS doesn’t use them but he only uses NITTO branded parts in most of his builds yet NITTO has one of the most research head drains out there.

Like I said I have one and for the peace of mind I would slap one on while the motor was out

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No, what I'm saying is if you do everything else properly, then you don't need a head drain bodged onto the back of the head.

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7 hours ago, WR33KD said:

 


So what there saying if I take my head drain off and my engine starves of oil they will be rebuild it for me.
 

No they say a lot of things but that is not one of them. Its a 200 page thread which contains the real life experience of many members as oil control is a very common problem with modified RBs. Although early in the thread (many years ago now) "head drains" were suggested as a possible solution if you read the last half or third of the thread you will find a consensus emerging. If you have so much oil pooling on top of the head that some of it finds its way down a drain at the back of the head above the floor level then you have other issues.

Reasons for oil starvation include inadequate capacity, over efficient oil pumps and excess pressure in the crankcase. A bigger, finned sump is one part of the answer, as are the installation of the right number and size oil restrictors. Boring out and relieving the oil drains in the head helps the return of oil to the sump as does reducing pressure in the crankcase with an outlet hose to the catch can which, if it is vented to the turbo intake will generate some negative pressure in the crankcase. My RB30 used to spew oil like a geyser until I made these changes and even then long periods at WOT (on the track only obviously) would start to fill the catch can which is why we run a drain from the bottom of the can back to the sump so that oil can drain back when you lift off.

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On 14/07/2019 at 12:20 AM, Frozengrip said:

refreshing the engine up as we speak. I have bought almost all the oil control issue mods ; bigger capacity sump from Lewis engines, n1 oil pump with billet spool gears to go along with it, head drain , oil restrictors, and nitto crank collar. Sound good ?

I would get both Spool gears & collar just to be super safe, however a Nitto pump and their collar would be ideal. I somehow destroyed the first revision of the Spool N1 gears. Currently running the 2nd revision of them, so let's see LOL.

Also spend your money on proper modern stainless steel injectors.

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No they say a lot of things but that is not one of them. Its a 200 page thread which contains the real life experience of many members as oil control is a very common problem with modified RBs. Although early in the thread (many years ago now) "head drains" were suggested as a possible solution if you read the last half or third of the thread you will find a consensus emerging. If you have so much oil pooling on top of the head that some of it finds its way down a drain at the back of the head above the floor level then you have other issues.
Reasons for oil starvation include inadequate capacity, over efficient oil pumps and excess pressure in the crankcase. A bigger, finned sump is one part of the answer, as are the installation of the right number and size oil restrictors. Boring out and relieving the oil drains in the head helps the return of oil to the sump as does reducing pressure in the crankcase with an outlet hose to the catch can which, if it is vented to the turbo intake will generate some negative pressure in the crankcase. My RB30 used to spew oil like a geyser until I made these changes and even then long periods at WOT (on the track only obviously) would start to fill the catch can which is why we run a drain from the bottom of the can back to the sump so that oil can drain back when you lift off.



So having the catch can return to the sump like you have, isn’t that a head drain?????

I have run my 25 on the track count less times now and have never had to drain my catch can. It’s a full built motor by St-hitec here in NZ. I run an N1 oil pump with remax oil pump gears can’t remember is 79 or 81mm and a winged sump

The rb26 I talked about was a new motor had just done it’s 1000km run in and it sent all the oil to the catch can and run the sump real low witch in turn run a bearing. At a quick guess a head drain could have pushed most of the oil back down to the sump, as the breathers are at the rear. It had oil restrictors and larger return gallerys but it still died and it was only a 260kw.

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39 minutes ago, WR33KD said:

So having the catch can return to the sump like you have, isn’t that a head drain?????

If you have that much oil filling up and running out of the cam breathers then you have bigger issues to deal with to be honest.

I think the name "head drain" is a bit misleading.. they're put in place to allow an equilibrium of pressure between the crank case and the head so you don't go blowing out dip sticks OR build up too much crank case pressure thus making it hard for oil to drain back down into the sump through the OEM channels.

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^^What he said.

Oil cannot flow down through the normal drains when there is a large qty of crankcase gases flowing up through the same holes. The drains inside the engine are big enough to get the oil back down. They're just not big enough on big power engines because big power = bigger crankcase gas flows, regardless of how good condition the rings, etc are.

Adding the oil drain at the back is not about specifically making a pipe for the oil to drain through. It simply adds more total area to the situation, so the gases flowing up through ALL of the holes (the ones in the engine, plus this new "drain") do so at a lower velocity, giving the oil a better chance of draining back against the flow.

If you put in hoses between the top of the sump and the cam covers, then you provide the same (or even more) flow area for the gases, and you don't have any pesky oil trying to use those hoses to go down. If these hoses go via a catch can, you get all sorts of win.

 

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3 hours ago, WR33KD said:

 

 


So having the catch can return to the sump like you have, isn’t that a head drain?????

I have run my 25 on the track count less times now and have never had to drain my catch can. It’s a full built motor by St-hitec here in NZ. I run an N1 oil pump with remax oil pump gears can’t remember is 79 or 81mm and a winged sump

The rb26 I talked about was a new motor had just done it’s 1000km run in and it sent all the oil to the catch can and run the sump real low witch in turn run a bearing. At a quick guess a head drain could have pushed most of the oil back down to the sump, as the breathers are at the rear. It had oil restrictors and larger return gallerys but it still died and it was only a 260kw.

Yes my engine was first built by Joe Kyle and tuned by Glen Suckling and then Soichi when he was still at ST Hitec. I took my car to Pukekohe,, Hampton Downs, Taupo and Manfield and it was a rare day that didn't include a pissed off looking RB owner pushing his Skyline or Cefiro etc on to a trailer with a dead engine.. I don't want to hammer the point about "head drains" except to say there are many factors that can lead to oil being blown out of the engine and after a few scares I think I got to the bottom of it to the extent that I ended up with a pretty reliable engine. Every car is different to some extent and there is a theory that a well built engine with all the clearances spot on will not be affected by blow by as much as some others (that promote pressurizing the crank case and opposing the return of the oil from the head). It may be part of the puzzle that you are benefiting from a well put together engine.

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50 minutes ago, joshuaho96 said:

For a 300kw RB26 is anything needed beyond baffled oil pan, oil pump, maybe a head restrictor, and air/oil separator?

That should do it but like I say every car is different and if your engine is out of the car I would put two fittings (and plug them) in the sump  in case you need them. If you look in the oil control thread you will find a table with recommendations for the size and number of oil restrictors.

Oil control usually only becomes a problem if you spend a long time at maximum revs which is rarely the case on the street.

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