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What Has Gone Wrong With My Rb26?

NismoR31Jet

By NismoR31Jet,
in Engines & Forced Induction

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NismoR31Jet Community Regular

NismoR31Jet

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Posted

Well, I was at sandown today giving the car its first track day with the 26. After one hard lap things looking bad. At full throttle above 6000 RPM the oil pressure would go from around 70 psi down to 50 and then start to fluctuate from 50 to 25 or so until I back off the gas and bring the revs back down to below 6 grand. Then after this happened twice I pulled into the pits and saw oil leaking from a cooler pipe. I removed the cooler pipe right infront of the plenum to find the plenum and cooler piping with a thick coating of oil in them. I am sure this oil is just blow by, as the engine has around 80,000 kms on it, but the swinging oil pressure has me baffled.

The engine itself is stock from an R32 GTR, with a High energy trap door baffeled sump, cam gears, power FC, rebuilt with steel wheel turbos, 3 inch exhaust and running around 15 psi it was making just under 270rwkw.

I now have the car home, it seems to be running fine but blowing a bit of white smoke, this could be from the oil in the cooler and piping tho. Oil is Mobil 1 5w50 and level is spot on.

What is your take on this, what can you see causing the oil pressure fluctuation?

I think a rebuild will need to be done, so now I need to work out what sort of rebuild do i want!

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T04GTR Grand Master

T04GTR

Posted
Posted
I now have the car home, it seems to be running fine but blowing a bit of white smoke, this could be from the oil in the cooler and piping tho. Oil is Mobil 1 5w50 and level is spot on.

thats the problem!!

gtr sumps are crap. you need to overfill them by about 1.5-2L for the track to stop OIL SURGE.

NismoR31Jet Community Regular

NismoR31Jet

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  • Author
Posted
thats the problem!!

gtr sumps are crap. you need to overfill them by about 1.5-2L for the track to stop OIL SURGE.

It isn't a GTR sump, but a High Energy trap door sump.

I have been told i may need restricters in the oil gallery to stop the oil from gathering in the head?

HRthirtyone Rising Star

HRthirtyone

Posted
Posted (edited)

could be rings or turbos, but if turbos were recently rebuilt, its prolly rings. do a compression test to see if you cracked a piston or something. it may still feel like its got all the power there and runs fine, but still have something really wrong with it.

all depends on how much oil your loosing into the pipes. also dont the older rb26 oil pumps tend to give up with lots of high rpm?

Edited by HRthirtyone
NismoR31Jet Community Regular

NismoR31Jet

Posted
  • Author
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Yep, I just read the 5 page thread on oil control by Sydney Kid. It seems to make a lot of sence, I guess all the blow by could be caused by the oil pooling up in the head?

I guess the oil control mods outlined in that post should be done, it can only help.

Yea ash, I will speak to benno tomorrow and suss it out. What bothers me is until I noticed the gauge I was pushing up to 7,500 a fair bit, so I am thinking I should replace the main and big end bearings just to be sure. And if I am doing the bearings I probably should to an R33 crank or fit the oil pump drive collar and a better oil pump while I am at it.

And then while I am at it I may as well re ring it or fit forgies, and the turbos will be off.....so a set of GTrs? turbs may find their way on too.......

Now do you see my problem? I have an ilness.....I am a modificationaholic.....I need help......

But my wife is encouraging a build.......so this is looking to be messy.....

700HP-GTR33 Mentor

700HP-GTR33

Posted
Posted

Have you changed the oil pump?

Did you install the cooler?

Do you have a catch-can?

I had my front main seals changed 3 times before I gave the mechanic a N1 oil pump.

I was also having oil pressure problems.

Luckily for me I had acted at the right time, the screws were nearly about to fall off.

Sometimes too there could be a blockage in the line, rare as it seems, some have been unlucky.

Get everything checked out before you go out again. or you may have to build quicker than you thought...

Hope I have been of some help.

Cheers :P

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

John - i know your issue, i have the same illness :P

Just remember, once its apart, it never ends cheap and it will cost you 5 figures end to end.

IMO - if the motor isnt dead and you check it out and its ok, dont touch it.

You have the steel wheels in there so you dont have the danger of it letting go. Just wait till it dies then pour the cashola into it.

Motors take a matter of weeks to be done, so its not like when it does die.. you'll be without a car forever

NismoR31Jet Community Regular

NismoR31Jet

Posted
  • Author
Posted

I hear where you are comming from man.

I am just worried I may have done some damage to the bearings with the oil pressure dropping at the revs I was pulling.

What engine is yours? Or more importantly, what crank and oil pump you using?

In the back of my mind there is the fact that mine is an R32 engine, and they are known for dodgy oil pumps.

I just want to make it reliable....

700HP-GTR33 Mentor

700HP-GTR33

Posted
Posted
I hear where you are comming from man.

I am just worried I may have done some damage to the bearings with the oil pressure dropping at the revs I was pulling.

What engine is yours? Or more importantly, what crank and oil pump you using?

In the back of my mind there is the fact that mine is an R32 engine, and they are known for dodgy oil pumps.

I just want to make it reliable....

Hello again,

All RB motors have a potentially dodgy oil pump, RB26 out of a 32 has a greater chance due to its age.

If you want to do track work safely ,get a larger sump and as Ash has stated, get some restrictors to stop the top from getting to much oil.

As you are getting a larger sump get the oil and water pumps. Jun oil pump with collar if you are really serious. Also get the Bearings ,Bolts and timing belt changed .

Then you might have a reliable car :laugh:

There are too many things that can go wrong with the RB26 motor....if not looked after properly.

The supporting mods. are endless but the Mod itself must be maintained for it to work.

Anyway like you and Ash, I too am a modoholic (?) .

Thus, I am on SAU to navigate my next steps. :)

Cheers and good luck :)

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I hear where you are comming from man.

I am just worried I may have done some damage to the bearings with the oil pressure dropping at the revs I was pulling.

What engine is yours? Or more importantly, what crank and oil pump you using?

In the back of my mind there is the fact that mine is an R32 engine, and they are known for dodgy oil pumps.

I just want to make it reliable....

You know what mine was, i did buy it off your cousin :wave:

Was a 32 motor, but obviously did the collar and what not as part rebuilt, and an N1 oil pump. Virtually the same as my 25 rebuild but in the 26!

Is there a was to check if you have done any damage? Ive got no idea on that one... if there is then that could save you some heartache.

Risking Grand Master

Risking

Posted
Posted

An oil pressure guage can give you a little indication of bearing wear.

Also you could look into an oil evaluation which can also give you a fairly accurate indication of bearing condition etc.

By far the best way is to pysically hold them in your hand and inspect them though.

Personally if its not rattling and carrying on id keep using it till she displays symptoms of bearing wear etc.

NismoR31Jet Community Regular

NismoR31Jet

Posted
  • Author
Posted

HAHA.......

After havin a chat with benno I am going to rebuild it regardless, as far as I know from what the inporter told me, it has 80,000 kms on it.....although....he also told me it was an R33 engine.....which it is not!

So yea....it is running fine now but it has got a fair bit of blow by, so might as well get it all sotred in one hit.

rob82 Mentor

rob82

Posted
Posted
You know what mine was, i did buy it off your cousin :)

Is there a was to check if you have done any damage? Ive got no idea on that one... if there is then that could save you some heartache.

Remove the oil filter and peel it open with a stong can opener and see if there is any copper coloured material within the filters.

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