Excessive Oil Running From Cam Covers Into Can

[abr33]

Cheers man, im doing alot of reading about the pumps breaking too, driving on only a portion of the flat parts on crank, i looked at my old pump and its got the same issue. i wish i knew this when i was building my engine as i have everything to do it at work! but its a matter or pulling engine out, then appart, a whole lot of stuffing around and involving time that doesnt exist...

[Dobz]

Are you using a stock sump?

[abr33]

yes

[DVS JEZ]

Cheers man, im doing alot of reading about the pumps breaking too, driving on only a portion of the flat parts on crank, i looked at my old pump and its got the same issue. i wish i knew this when i was building my engine as i have everything to do it at work! but its a matter or pulling engine out, then appart, a whole lot of stuffing around and involving time that doesnt exist...

I did the same. Built my rb26 did 2000ks then read about the oil control issues and pulledi

It back apart. Got a tomei pump, sump baffles , oil restrictors and did the rear head oil drIan. The tomei pump and new headgasket was the worst part. Hurt the wallet abit

[Dobz]

Overfilling 2L and having a stock sump is definatley contributing to the problem due to excessive oil being churned up by the crank under accelaration. I know there is no pressure that builds up in the sump under normal conditions. On the other hand when you get a lot of oil surge getting churned up by the crank all that oil flying around at high speed does cause some pressure, enough pressure to slow the drainig of oil from the head back to the sump. That explains why it doesn't happen on the dyno because no oil surge= no oil getting sucked up into the catch can.

As has already been said... put the catch can to atmosphere and don't overfill the sump so much.

[MrStabby]

0-40w wont be helping you..too thin..

Can you explain why using a "thin" oil is related to his problem?

this is a 40year old engine design, it was made to run on 20/50w when new. least i would use is 10/40,, just my view..

Can you quote a source that states 20W-50? FWIW the R32 GTR workshop manual says 7.5W-30 is the correct grade.

Do you realise that a 0W-40 and a 10W-40 are the same viscosity at operating temperature?

[r33_racer]

This should help you get an idea.

[rockabilly]

i suspect the issue is related as with all these large power build to the fact that 400kw,s is almost double the std output. yes nissan recommended 7.5/30 for a 250bhp rb25det. once you stick some forged pistons in there with twice the piston to bore clearnance than std, an oil pump that flows almost 1.7 times more than stock and alot larger amount of air pressure from a bigger turbo the factory specs go out of the window. i should have wrote 15/50w which is what alot of the big power cars tend to use. .yes you can fit oil rstrictors and oil drain all will help. in my eyes thinner oil in a big power car always seem to be an issue, seen it many times before, if is not leaking everywhere its blowing out everywhere. i just think its no suitable..my own views. as for 20/50w,this block was used along time before nissan ever put a twin cam head on it.the oil grade change had to be as you cannot run a turbo car on a multigrade oil, it burns it. so we have a 40 year old crank designed for 20/50w, running a turbo or two. maybe in oz people use a 0-30w oil, but i have never seen a car run it here in the uk, especially a big power car, which for an rb25det this is..

[djr81]

0-40w wont be helping you..too thin..

this is a 40year old engine design, it was made to run on 20/50w when new. least i would use is 10/40,, just my view..

Nissan specified 7.5W30. Understand that it gets much colder in Japan than Oz. Most people are happy with 10W50 which is the cheapest of the Mobil 1 viscosity range. Other people who use other oils end up with different ranges.

Anyway it is not really the fault of the oil.

Also make sure the blow by has somewhere to go. Which means running a PCV. Cars without them spit more oil.

Edited February 21, 2011 by djr81

[simpletool]

Oil viscosity shouldn't have much of an effect on this. Thinner oil would just circulate quicker but in the end the result would be the same. The pump and drain effects should roughly cancel each other out. Trying to utilize oil viscosity to solve this is a band-aid fix, at best. You should use the correct viscosity as determined by the operating temperature and desired oil pressure.

Edited February 21, 2011 by simpletool

[Beer Baron]

Personally i think 2 litres overfilled is way too much, usually only gtr boys do it due to the extra g forces, and only by 1 litre, however it may have saved your engine. Im pretty sure to fit the rear oil drain you have to pull the head anyway, and to fit an oil pump, you have to pull the timing belt and sump. If it were me , i would use thicker oil only .5 litre overfill, and boot it once, check the catch can, if it is dry, then boot it twice and check again.

There is a lot of debate ver the head drains, but i cant see them making anything worse. I would be pulling the head if the oil doesnt fix it, and doing the restrictors and the drain if you are inclined.

agree. first thing is stop filling the sump over-full by 2 litres. that is probably part of the problem. like adriano said I would do half a litre for starters and I would be switching to a 10W40. standard oil from new was a 7.5W30 from memory (and a mineral blend at that). but either way a 10W40 is a much better option. try it.

[abr33]

cheers guys your all full of great info, today i ordered some 10w60 oil as its the closest in the edge sport range, and ill vent can to atmospheric, and im also putting a drain back from can to sump, im not going to fit a crank collar (for now) as my tuner said its only an issue when revving over 8k usually, and im limited to 7600 but the auto changes gears at 7500ish now. i will in the future (or not so distant future if i cant stop this oil blowing out) pull motor out, make crank collar and fit it, build a big sump extension with baffling and gates and drain back at rear of head. but for the moment, im happy with my 260kw providing i stop the oil coming out ill leave it as is for time being. ill be fitting a really good oil pressure gauge too to keep an eye the situation.

Im guessing its overfull by 2 litres I havent measured it, but its about 25-27mm over the full mark if anyone knows about how much extra.

Thanks everyone

[Dobz]

Using an auto your oil pump wouldn't get harmonic vibrartions as bad as a manual so it'll be a less prone to breakage anyway.

As for your oil approx. 5-6mm over the full mark should give you about .5L extra.

[grimreaper]

sorry to hijack but i have a similer problem with my rb20det and filling the catch can up i was thinking of puting a drain of the catch can back in to the sump , not to shore if it is a good i dear or not as my car gets driven hard on the track a lot . any thoughts on if that is a good idear or not to have the catch can drain back in to the sump

[r33_racer]

If you do alot of racing on the track does that mean you change your oil more often also?

If you do then go for it.

[grimreaper]

If you do alot of racing on the track does that mean you change your oil more often also?

If you do then go for it.

yer it gets changed very regualy, i was more conserned about any crap geting back in to the sump that gets court up in the catch can ( after just thinking about it , if i tap a hole in 20mm up from the bottom for the drain to the sump any crap that getis in there will sit on the bottom)

[r33_racer]

If it is a sealed breather can with a good filter, what crap are you thinking will get in and back to the sump?

[grimreaper]

If it is a sealed breather can with a good filter, what crap are you thinking will get in and back to the sump?

i have noticed latly there is a milly residu on the inside of the lid and some condensation as well , also the oil in the catch and is turning milky from that , the car hasent been driven much over the last 12 months , after looking every else the oil that is n the lines is not milky and cant find anere where else it is coming from other then the condensation on the lid of the catch can ?

[abr33]

i have noticed latly there is a milly residu on the inside of the lid and some condensation as well , also the oil in the catch and is turning milky from that , the car hasent been driven much over the last 12 months , after looking every else the oil that is n the lines is not milky and cant find anere where else it is coming from other then the condensation on the lid of the catch can ?

Its because everytime your engine slowly cools, it sucks air in and the moisture in the air evaporates to lid and a bit mixes with oil residue and makes it white, basically anyway