Disappearing Oil

[Don Dada]

Hi guys

I've noticed my Rb26 (R33) slowly looses oil over a period of time.

I've done two oil changes so far since i've had the engine and had to top up about 3/4 to 1 quart over the 4000km i run the oil for.

The first time i used Redline 20w50 and thought it was just probably the oil so i tried Schaeffer 20w50 but same result.

There are no oil leaks anywhere and when i opened the catch can after the two the oil changes there was only just enough oil just to cover the bottom(greddy)..... just a few drops really.

Compression reads: 172 / 175 / 173 / 170 / 156 / 160.

There is no smoke on start up, and my friend who was driving behind me says there is only some black smoke for a few seconds when i floor it.... no blue smoke.

It is running really rich because it has a little soot on the back and pops every now and again when a let go.... stock ecu running 12psi

Other wise car pulls really good

Where does my oil go???

[STATUS]

burnt.... probably oil control rings in number 5.

[Don Dada]

any tell tale signs??

Wet plug maybe?

The lifters are noisy too.

[The Dan]

Check your cam cover gaskets. Notorious as shit on any skyline of its age. I'm forever replacing them for customers that lose around half-1 litre of oil every 5000km.

And it won't be your oil control rings, all they do is drag oil up the bore. Even if you were referring to the second ring it wouldn't be that unless it was blowing smoke, which he said it wasn't.

[Don Dada]

The cam cover gaskets do leak a little.... but definitely not a quart over the 4000km period.

[Don Dada]

Just wanted to know if it's common to have to top up oil between changes on rbs particularly on the 26 due to the twin set up

[The Dan]

Just wanted to know if it's common to have to top up oil between changes on rbs particularly on the 26 due to the twin set up

Yes it is quite common when you have leaking rocker cover gaskets

[Granthem]

Yes it is quite common when you have leaking rocker cover gaskets

[CRoNic...]

Rb26's do burn oil as per normal, but I don't know how much?

Oil seals aren't leaking? Although you'd probably see smoke for that...

[Don Dada]

Yes it is quite common when you have leaking rocker cover gaskets

Actually i do recall hearing this some where before.....can't put my finger on it though

Anyone with a daily driven 26????

[The Dan]

The only reason why I'm repeating it is because when you are losing oil...and you know you have a leak somewhere....no matter how big or small, fix the leak first, then ask the question.

It's common sense. It's also at the top of the engine so it's the best place to start considering the oil will move in a downward direction.

Here's a picture of a GTST with a normal leak from the rocker cover gasket.

It was also leaking from the front corners behind the top timing cover backing plate and leaking from the half moon seals at the back and leaking down on top of the gearbox.

This one appeared not too bad from the top. It wasn't until looking from underneath that you will see where it is coming from.

[BeEnAr]

My 32GTR is daily driven about 110km each day of the week and I don't lose oil like you are stating. I had the rocker cover leak at one point but just tighten the screws up regularly now and don't see the issue anymore. But it is apparently a common thing for the rocker covers to work lose.

[STATUS]

id just about put money on a hurt cylinder, you wont see it burning. LS1's had the same issue 1 litre per 2500km's and most owners could not find the source.

[TriniGT]

Damn that 5th cylinder and even the 6th are a bit of a drop over the others. Usually they are within 5-10 of eachother, maybe the oil is being burnt on startup and then not noticable after?

[Don Dada]

Nissan says the standard is 170 psi with a variance of 14 psi across cyl so the lower numbers (156,160) is what i would actually expect for an engine with this kind of mileage .....water pump,timing belt,tensioner etc. has already been changed in Jap.

Its the higher numbers that has me baffled bc i tested a next 26 with a genuine 25k on the clock using the same gauge and all cyl were between 162-170

[The Dan]

Nissan says the standard is 170 psi with a variance of 14 psi across cyl so the lower numbers (156,160) is what i would actually expect for an engine with this kind of mileage .....water pump,timing belt,tensioner etc. has already been changed in Jap.

Its the higher numbers that has me baffled bc i tested a next 26 with a genuine 25k on the clock using the same gauge and all cyl were between 162-170

Did you have a jump pack connected, throttle fully open and all spark plugs out for the compression test?

If not, then the results don't mean anything as they will most likely be a few psi off...usually under

[Don Dada]

yep

[Beer Baron]

I have never had to top up oil on any of my RB26s and i've had a fair few, from stock 1989 engine to brand new N1 Nur motors to built motors and none of them used oil between changes. granted my changes tend to be fairly quick as most got some track use and get fresh oil then, but they always gave back out pretty much what was put in. there is definitely something wrong happening. in normally healthy state RB26s do not burn or loose oil.

[The Dan]

yep

Exactly how much oil are you putting in at the service

[Don Dada]

5quarts