Oil Control In Rb's For Circuit Drag Or Drift

[Shockster0429]

Sk would have noted that already on the RB powered race cars he deals with, so clearly not a problem. I'm about to pull down my 25 that I had blocked the front supply off on so will know soon enough.

Clearly this is not just a return problem but a oversupply problem at high RPM as well, hence the restrictions.

correct.. if tomei makes the restrictors obviously its a oversupply issue... why make something that isnt needed.

[Sydneykid]

1. has anyone who has done this modification of restricting oil flow and lowering oil pressure to the cam journal bearings noticed increased wear?

2. the problem seems like its an oil return, not a supply problem.

3. if you restrict the flowrate the cylinder head doesnt recieve enough cooling.

4. also the pressure drops because of the restriction and you now have issues with maintaining the hydrodynamic lubrication of the journal bearings. this leads to increased mechanical contact between the bearing surfaces.

5. why not do as is already suggested and improve return oil flow? increasing oil gallery size and added external lines are perfectly fine.

1. Yep we are up to 32 engines now and not one has any sign of oil starvation of the camshaft bearings

2. It is both

3. RB26's have one of the oil supplies blocked off STANDARD, Nissan seems to think its necessary for STANDARD RB26 rpms as used on the road.

4. The pressure before the restrictors INCREASES under certain cirumstances, that means superior lubrication for the main and big end bearings. Refer to #1 regarding the camshaft bearings

5. Because sometimes it's simply not enough, depending on your usage patterns and the sustained engine rpm. The only time I don't have to limit the flow to the cylinder head is when we use a dry sump sytem running partial vacuum on scavenge. The 4 scavenge stages have considerably more flow capability than the pressure stage. We don't get excessive oil build up in the cam covers then.

cheers

Edited October 17, 2006 by Sydneykid

[Guilt-Toy]

ever since i blocked off my oil line and restricter the other I have had major lifter noise when the car is driven slowly and cruising to work. As soon as i start hitting boost or idle in traffic for a while (engine gets warmer) the lifters stop making noise. but oil does not escape from catch can anywhere near as much now then it used to before the restrictors were installed.

Its annoying. tried all kinds of oil...

Castrol Edge 5w30

Penrite HPR40

Castrol GTX3

Castrol 15w40 (best result)

The thicker the oil the noisier the engine gets. compression tests showed 145 155 120 155 140 150 (cold engine)

I think my lifters are screwed... the noise does sound like its comming from the top of the engine.. I have been thrashing the crap outta the engine and no change..

Maybe i have oil gallerys blocked in my head or something ? I get lots of oil splashing in the cam covers...

Engine makes noise but goes great. I have a bottom end as a backup for forgies and rods because i was told the bottom end is what is buggered by a few people yet others tell me its oil starvation to the lifters or the lifters are screwed. sound is definatly comming from the top of the engine and allways goes away when the engine has been given a hard time or sitting in traffic for a while.

Everyone i go to gives me a different opinion. confusing

[AndrewD]

1. Yep we are up to 32 engines now and not one has any sign of oil starvation of the camshaft bearings

2. It is both

3. RB26's have one of the oil supplies blocked off STANDARD, Nissan seems to think its necessary for STANDARD RB26 rpms as used on the road.

4. The pressure before the restrictors INCREASES under certain cirumstances, that means superior lubrication for the main and big end bearings. Refer to #1 regarding the camshaft bearings

5. Because sometimes it's simply not enough, depending on your usage patterns and the sustained engine rpm. The only time I don't have to limit the flow to the cylinder head is when we use a dry sump sytem running partial vacuum on scavenge. The 4 scavenge stages have considerably more flow capability than the pressure stage. We don't get excessive oil build up in the cam covers then.

cheers

Sorry for point 4 i meant decreases after restriction. i left bit out

Are all 4 of your scavenge stages from the sump? or do you use some for the return oil from the head? any of the stages used for scavenging turbocharger routed oil?

What type of pump is the standard internal pressure pump and the external scavenges? gerotor or roots style?

Edited October 17, 2006 by AndrewD

[Sydneykid]

Sorry for point 4 i meant decreases after restriction. i left bit out

1. Are all 4 of your scavenge stages from the sump?

2. or do you use some for the return oil from the head?

3. any of the stages used for scavenging turbocharger routed oil?

4. What type of pump is the standard internal pressure pump and the external scavenges? gerotor or roots style?

1. On GTR's we run 2 scavenge pick ups from the sump. One in front of and one behind the front drive shaft.

2. Plus 1 scavenge pick up from each cam cover.

3. Nope, it's all frothy and foamy after its been though the turbo, so best to gravity feed it into the block.

4. The standard RB oil pump is the normal rotor style. We use Peterson dry sump pumps, they are gerotor style as you would expect.

cheers

[N1GTR]

SK, Have you got any pics of the "scavenge" pickups by any chance?

Thanks

[Abo Bob]

What about this concept of putting some fuel cell foam in the cam covers somewhere?

Can someone explain it to me? Does it work?

Ps I built my engine before this thread was started and didn't pm SK to ask about oil control.

[Beer Baron]

fuel cell foam in the cam covers doesn't sound like a good idea to me. one i can't there where you could really fit it and two it would hold oil which is bad as you want the oil flowing back to the sump. cam cover baffles are a good idea though.

[700HP-GTR33]

It is funny how a problem is solved and a question on how it is solved comes up.

Then solving the problem leads to creating another problem and the question is asked

on how to solve the problem.

I feel for you guilt-toy.

Low oil levels up the top end will only cause you other problems.

We are always learning , making mods and changes and trying to keep the whole thing working out on the track or on our roads.

On this issue of over-supply to the top end I am quite baffled.

The Oil pump forces oil and at high revs forces to much oil and leaves nothing in the bottom

to pick up.The over supply is not hurting the top end and thus the catch can was developed.

Oil is needed even at low revs and insufficient supply of oil up the top end is what you might have a problem with.Putting restrictors on the lines to slow the oil only will harm the motor.Cooling is needed quickly

for the Pistons and moving components and slowing this flow down will only cause long term problems.

Can we look at this question of oil problems in Rb's from outside the square.

Is it all possible to have a regulator , that will at higher revs restrict oil flow safely and at low revs

remain as factory.Surely this way of thinking is were we should be headed.

Making holes for better flow,restricting hoses to slow the volume etc,etc,etc.seems funny to me.

I am not an engineer but can see the problem ,Could an external Oil Sump with a regulator be

mounted in the engine bay ?

This can increase our Oil Supply and restrict flow at high RPM.

It would be installed like a cooler and work only for the supply of oil to the top and bottom end.

Hope I have not scared anyone ,just my two bobs

[Beer Baron]

it's not that big a problem. it's pretty simple. you need sump baffles to stop oil surge. if you are running an aftermarket pump that pumps a greater volume of oil at a given pressure AND you see a fair amount of high revs then you need to slow oil flow to the head, and facilitate more oil returning to the sump (enlarged returns and external return). if you think those ideas are no good then you go to dry sump. problems solved.

[700HP-GTR33]

it's not that big a problem. it's pretty simple. you need sump baffles to stop oil surge. if you are running an aftermarket pump that pumps a greater volume of oil at a given pressure AND you see a fair amount of high revs then you need to slow oil flow to the head, and facilitate more oil returning to the sump (enlarged returns and external return). if you think those ideas are no good then you go to dry sump. problems solved.

Great,

Not every-one has the $$$$$$$ to just get the Engine and high flow the oil ports remove it install a baffle ,

let alone go dry sump..

There still might be a possibility the pump runs out of oil, so then now you suggest a sump extention.

The list goes on and on and on....like this thread.

Richard, did you understand anything I wrote?

My solution was a product that gave us a larger supply of oil that restricts flow at high revsat the top end, simple.

This could also supply more oil to the bottom when restricting the top, allowing no low oil levels for the pump.

Sydneykid , does this sound stupid or is this why you started this thread in the first place?

Cheers

Edited: the external sump can be built with a baffle to stop the surge..........it can work.

[Guilt-Toy]

its all about how much money you have to spend.. my car is a daily driver as i do 140km in it each day to go to work and back.

My mate (mechanic) keeps telling me to put solid lifters in it which will solve the problem...

Anyone else have anymore ideas? if i take the car out on the weekend and drive it hard etc there are no issues.. its only when i drive on the freeway at 2800rpm - 3300rpm for long periods of time or when the engine is cold when i get the noises...

[AndrewD]

What about the internal pressure relief? (that would return excess oil to the sump before being sent up to the head)

Is there not one?

[Sydneykid]

It is funny how a problem is solved and a question on how it is solved comes up.

Then solving the problem leads to creating another problem and the question is asked

on how to solve the problem.

I feel for you guilt-toy.

Low oil levels up the top end will only cause you other problems.

We are always learning , making mods and changes and trying to keep the whole thing working out on the track or on our roads.

On this issue of over-supply to the top end I am quite baffled.

The Oil pump forces oil and at high revs forces to much oil and leaves nothing in the bottom

to pick up.The over supply is not hurting the top end and thus the catch can was developed.

Oil is needed even at low revs and insufficient supply of oil up the top end is what you might have a problem with.Putting restrictors on the lines to slow the oil only will harm the motor.Cooling is needed quickly

for the Pistons and moving components and slowing this flow down will only cause long term problems.

Can we look at this question of oil problems in Rb's from outside the square.

Is it all possible to have a regulator , that will at higher revs restrict oil flow safely and at low revs

remain as factory.Surely this way of thinking is were we should be headed.

Making holes for better flow,restricting hoses to slow the volume etc,etc,etc.seems funny to me.

I am not an engineer but can see the problem ,Could an external Oil Sump with a regulator be

mounted in the engine bay ?

This can increase our Oil Supply and restrict flow at high RPM.

It would be installed like a cooler and work only for the supply of oil to the top and bottom end.

Hope I have not scared anyone ,just my two bobs

Piston cooling (same as main bearing and big end bearing supply) is done from below (before) the oil flow restrictors. So restricting the oil flow to the cylinder head in fact improves the piston under crown cooling.

Please remember that Nissan blocks off one oil supply in RB26's standard. So there is nothing unusual or unrealistic in doing that. What we are doing (that Nissan don’t) is to restrict the oil flow further (than they do) by using a smaller orifice restrictor. Noting that Tomei, Jun, HKS and Apexi all use restrictors, so it is a well know technique.

The oil pump’s flow basically increases as rpm increases, at least until the predetermined oil pressure is reached. Then the flow is constant. The pressure is controlled by the oil pressure relief valve, which bleeds off oil flow at the oil pump outlet and returns it directly to the sump.

The first problem occurs when people use constantly higher rpm than Nissan ever envisaged together with a higher oil pressure relief (N1 for example). This is further exacerbated by using a larger flow oil pumps (Jun, HKS, Tomei etc).

Keeping the above in mind, what I have done with the table is to give a gradual decrease in the amount of oil flowing to the cylinder head in relation to the oil pumps and rpms used. Simplistically what I have done is to give the SAME (not less) oil flow as the engine would have had when the oil pump and rpm used were standard.

How do I know it works? Well, we have done over 30 engines using this technique since 1998 and not one of them has had a camshaft bearing wear problem. That’s a pretty good sample IMHO. But (as I say often) every engine is different, so use your own discretion when selecting the appropriate restrictor for your uses.

cheers

PS, the table also mentions the fitment of an oil cooler

Edited October 18, 2006 by Sydneykid

[Sydneykid]

its all about how much money you have to spend.. my car is a daily driver as i do 140km in it each day to go to work and back.

My mate (mechanic) keeps telling me to put solid lifters in it which will solve the problem...

Anyone else have anymore ideas? if i take the car out on the weekend and drive it hard etc there are no issues.. its only when i drive on the freeway at 2800rpm - 3300rpm for long periods of time or when the engine is cold when i get the noises...

Start up hydraulic lifter rattle is the first sign of lifter wear. It is most commonly caused by worn oil seals in the lifters. The oil leaks out over night and when you start the engine first thing in the morning it takes a little while for the oil to firstly fill up the empty lifters and then build up pressure. Replacing the lifters usually fixes this.

If the lifters are not replaced, then the wear rate increase exponentially due to the lack of oil. Eventually the lifters can't hold the oil pressure at all and the rattle comes back at low to mid rpms. Replacing the lifters will fix this.

Eventually the lifter get so badly worn that they rattle all the time. This can lead to damaged camshaft lobes due to the excessive clearances.

So my first suggestion is to replace the lifters.

I should mention that some lifter rattle is caused by too infrequent oil changes and a resulting build up of sludge. This causes blockages in the oil flow into the lifters, hence they rattle. A few oil changes usually fix this problem, not that I think it is the case for a Skyline enthusiast, we change the oil too often for that.

At this point it is worth expanding on the discussion of RB25 oil supply. They have 3 oil feeds, one for the VVT which overflows into the cylinder head and has its own return to the sump located on the front LHS. The other 2 are the normal RB oil feeds to the camshaft bearings.

I can’t remember what you have done regarding the VVT oil supply, but from what I have seen it should always be left in place, untouched if the VVT is being used. Then selecting from the 1.0 mm 1.25 or 1.5 mm restrictors according to the usage. Refer to the table for the exact details.

Lastly oil pump, if the oil pump is not achieving maximum oil pressure (and therefore flow) by 3,000 rpm, then you have an oil pump problem. Revving the engine to higher rpms should not result in higher oil pressure. If it does, then you have an oil pump problem that needs to be fixed.

Keep in mind that a swap to solid lifters will also require a swap to camshafts designed to run with solid lifters.

Hope that has been of some help

cheers

[Guilt-Toy]

Thanks SK...

I just organised a second hand RB25 head that had good lifters in it and I am picking it up tonight - (second head ive purchased to change the lifters) so this will be the second set of lifters to go in.

Will replace the timing belt as well and check the idlers.

Thanks for advice.

Could the lifters be the reason why number 3 is a little down on compression?

[Cubes]

Lifters wont cause it to be down on compression.

How are the injectors? They have been flow tested?

Maybe the motors been running a little too lean on cruise resulting in dead rings? Or maybe it was a manufacturing fault?

[Abo Bob]

Piston cooling (same as main bearing and big end bearing supply) is done from below (before) the oil flow restrictors. So restricting the oil flow to the cylinder head in fact improves the piston under crown cooling.

Please remember that Nissan blocks off one oil supply in RB26's standard. So there is nothing unusual or unrealistic in doing that. What we are doing (that Nissan don’t) is to restrict the oil flow further (than they do) by using a smaller orifice restrictor. Noting that Tomei, Jun, HKS and Apexi all use restrictors, so it is a well know technique.

The oil pump’s flow basically increases as rpm increases, at least until the predetermined oil pressure is reached. Then the flow is constant. The pressure is controlled by the oil pressure relief valve, which bleeds off oil flow at the oil pump outlet and returns it directly to the sump.

The first problem occurs when people use constantly higher rpm than Nissan ever envisaged together with a higher oil pressure relief (N1 for example). This is further exacerbated by using a larger flow oil pumps (Jun, HKS, Tomei etc).

Keeping the above in mind, what I have done with the table is to give a gradual decrease in the amount of oil flowing to the cylinder head in relation to the oil pumps and rpms used. Simplistically what I have done is to give the SAME (not less) oil flow as the engine would have had when the oil pump and rpm used were standard.

How do I know it works? Well, we have done over 30 engines using this technique since 1998 and not one of them has had a camshaft bearing wear problem. That’s a pretty good sample IMHO. But (as I say often) every engine is different, so use your own discretion when selecting the appropriate restrictor for your uses.

cheers

PS, the table also mentions the fitment of an oil cooler

It seems that everyone is just reiterating their opinion rather than discussing the things that 700hpgtr brought up. It's just an idea. Why not discuss it? Maybe it will lead to a dead end, maybe not. Sure people have worked out other ways and those ways work but are there yet to be explored possibilities?

I was going to suggest an external oil pump with pressure regulator so that pressure is not rpm related but I don't want to get shot down in flames.

[Sydneykid]

It seems that everyone is just reiterating their opinion rather than discussing the things that 700hpgtr brought up. It's just an idea. Why not discuss it? Maybe it will lead to a dead end, maybe not. Sure people have worked out other ways and those ways work but are there yet to be explored possibilities?

I was going to suggest an external oil pump with pressure regulator so that pressure is not rpm related but I don't want to get shot down in flames.

What part of his post didn't I answer?

Low top end oil levels - covered

Cooling pistons - covered

Oil supply at low rpms - covered

Oil flow regulator at high rpms - covered

External oil pump = dry sump, I don't think that needed covering again

What have I missed?

cheers

[Roy]

Regs, etc etc? You have a relief valve/by-pass that opens when a certain pressure is reached. Its a spring...so its kinda bound by the laws of fluids and pressure.

The oil pump is driven off the crank, so a gain is a fixed machanical relationship of rpm and flow. You cant really put a clutch on it, or readily change the drive relationship.

Good ideas, but cant be practically done, let alone cheaply. Eeplace the spring in the oil pump with a solenoid of variable lift that bleeds pressure and affects flow...but again costly to develop, Damage to motors in getting it right...and another control system that can go wrong or short out.

The problem isnt that big a problem is it? If you have a std GTR, over fill the engine a little, have a catch can that flows back into a tee in your dipstick etc. Cheap, sensible and will do the job.

If you have your engine apart then sure spend some money on oil control....but hell. Sumps, baffles, head restrictors, oil return lines????? Is it really that complicated? How many ppl actually stress their cars to warrant the expense. Cool if you can do it all...but look at the big picture? Is this all the added expense you have to consider if you are freshening up a motor?

Its a problem, but bandaids will work well....wont they? Anyway, im buying the parts and let the engine builder tell me what i need....I hope you dont need to amputate the leg and install Steve Austins bionic leg????