Oil catch can filling up at the track... y?

[gawdzilla]

At the track under a lot of high rpm, my oil catch can (vented to atmosphere with a big breather filter) is filling up with oil. 20 minute session probably puts a good 16 oz into my catch can. my pan is heavily topped off to prevent any possible starving.

i'm runnig 10w30. my guess is the oil is too thin for track use and the repated high rpm with oil temps 220-240F are turning the oil into a water-like viscosity. i'm thinking the valve cover gases going to my catch can are just carrying liquid oil into my catch can. i'm relatively certain it's not "blowby" due to the sheer amount of oil. normal driving with occassional wots liiterally puts 1-2 drops of oil in my catch can after weeks of driving, and maybe a few tablespoons of water condensation. this time at the track it was completely different.

next track day i'll probably run 15w50 or so and report back.

Thoughts?

[240z4u]

For what its worth, I think your on the right track. Something heavier would be worth a try.

Can't imagine another reason why it would be happening unless you have way too much oil in there!

[gawdzilla]

yea... i think the oil is just getting moved since its a high pressure to low pressure difference, and the oil itself doesn't have much weight to settle out of the valve cover baffling fast enough

[Darius]

When I was street tuning last summer on a cool muggy morning, my catch can filled almost half way up with oil and water vapor. 50/50 mix. Just be careful if you have a breather filter on the catch can and there's that much vapor going through it, because it will plug and the crank case will pressurize. The exhaust will start smoking like crazy from the blowby.

[gawdzilla]

When I was street tuning last summer on a cool muggy morning, my catch can filled almost half way up with oil and water vapor. 50/50 mix. Just be careful if you have a breather filter on the catch can and there's that much vapor going through it, because it will plug and the crank case will pressurize. The exhaust will start smoking like crazy from the blowby.

i've had that happen once when i was running just breather filters on top of the valve covers. they got soaked in oil and clogged and i got huge white smoke clouds out the exhaust.

this time it's different. just getting a lot of oil in the catch can but i'm pretty certain its not an indication of exessive blowby or worn rings

[Darius]

I am curious to know if there's enough oil built up in the head under hard acceleration that upon heavy braking (corner at the end of a straight) there's enough oil to slosh to the front of the head and around the baffles to the valve cover outlets?? I'm trying to throw out ideas here even though that might not make any sense with the way the baffles are set up.

I noticed when I cut open the stock valve cover vent line that comes from the RB25 vertical fitting that there is a little metal puck with a 1/8" hole in the center of it. Do you know if the RB26 had something like that?

[gawdzilla]

its hard to say how the oil is travelling around under the valve cover. since i didnt do the head restrictor or the real head drain mods, maybe my head is filling excessively with oil. i highly doubt it is to the point that each valve cover is ENTIRELY filled because that would leave no oil in my sump. there is probably just a fair amount of splashing and since the oil catch can and breather are lower than the height of the valve covers and also low pressure compared to inside the valve covers themselves... oil is probably being squirted out from high to low pressure, as well as siphoning out from gravity and the pressure difference. that's my only explanation...

ive never had (or looked at) the factory breather lines so i don't know if there is a restrictor in them.

[gawdzilla]

ordered the mines triple flow cam cover baffle plates. i'll post up about how they do.

http://www.mines-wave.com/engl...E.htm

[USMCgetsome]

great find. I never really put any thought into the oil head drain mod. But i see now how important it is. Its impressive to see most known tuning shops have addressed this issue and have a product for it. I feel like were always behind the power curve here in the u.s.

[raremotive]

how much you get your tri baffle plate for? n1 valve baffles are longer than stock.

I do like to hear more about your oil weight theory/experiement.

I am not a fan of the rear drain mod. Nissan never thought it was an issue hense.. not doing anything to the past 12 years that the gtr was out.

I do instead gasket match the oil return between the block and the head. If you are using a modified gtr oil pan, there's traps in the oil pan with tiny drain holes to drain the oil out, I enlarge them to let more oil drain. I am still working out a oil return baffling on the oil pan, still in planning stages.
Modified by Rare_f8 at 2:27 PM 7/20/2008

[HxC_Nismo]

+1 where did you buy em from?

[Blown240sx]

Are you blowing by that much before over filling or after? Over filling is going to cause some blow by issues also.

If you have excessive blow by hook a hose to one side of the catch can going to the intake hose and another to the head and the suction should draw a lot of the crank pressure out reducing blow by.

[gawdzilla]

how much you get your tri baffle plate for? n1 valve baffles are longer than stock.

I do like to hear more about your oil weight theory/experiement.

I am not a fan of the rear drain mod. Nissan never thought it was an issue hense.. not doing anything to the past 12 years that the gtr was out. Modified by Rare_f8 at 2:27 PM 7/20/2008

got the tri baffle plate for $287 shipped from rhdjapan. like $260 something if you go overseas mail but id like to install them before an event in august. not the cheapest thing, but it's Mine's. I think the retail price is around $200-220 w/o shipping. yea the n1's are longer than stock but i figured it would be harder and slower to get those than the Mine's parts.

not a fan of the rear drain mod myself either... but that's just my opinion.

+1 where did you buy em from?

rhdjapan

Are you blowing by that much before over filling or after? Over filling is going to cause some blow by issues also.

If you have excessive blow by hook a hose to one side of the catch can going to the intake hose and another to the head and the suction should draw a lot of the crank pressure out reducing blow by.

it doesn't seem to be affected too much by the overfill. i have my oil usually filled to the first hump on the dipstick. maybe .5 qt over the high mark. on street driving (with occassional WOT runs but not back to back like the track), my catch can BARELY fills. literally 3-5 drops of oil after weeks with about 30 drops of moisture on top. i can see how overfill might affect drainback into the pan because theres more oil normally in the sump maybe partially blocking the gravity returns

i think hooking a hose to create more suction out of the valve cover will make it worse. oil is getting caught between the blowby gas and the valve cover exits. if there is a vacuum it will just suck the oil and blowby gas out faster. if you take a look at the Mine's diagrams, the light blue is the blowby gas sitting behind the yellow oil. Once oil reaches the valve cover exits, it seems the blowby gas is just going to push it out. the idea behind the baffle plates is to keep the oil from getting to the valve cover openings. In theory it seems like a good idea, so i'm giving it a shot

[Blown240sx]

Just saying though that a build up of pressure in the first place could cause the blow by. IDk I figured a 3 dollar hose was worth a try before spending more.

[gawdzilla]

just a followup. i put these in and they WORK. install was pretty straightforward and of course fitment was perfect as i expected. blowby has been reduced from about 16 oz of oil over 20-minute track session to about 2-3. i'm pretty happy with the results

[Shocker]

just a followup. i put these in and they WORK. install was pretty straightforward and of course fitment was perfect as i expected. blowby has been reduced from about 16 oz of oil over 20-minute track session to about 2-3. i'm pretty happy with the results

Nice to know Gawd, too bad they dont make one for the 25 cover's.

[SullivanRacing06]

i run rotella 15-40 oil all the time, i had the same issues w my greddy can filling up, sorta sucks to see but that happens with righ revs and boost on any motor

[meet07]

I dont have a catch can and thought that my turbo was blown when I found oil from the hot pipes all the way up to the tb. How much blowby is normal?? A buddy of mine has a g20 and they come from the factory with a plastic catch can and draing back to the pan...

[RustspecS13]

Meet- the first drift pratice I went to with my RB I had tonns of oil in my intercooler piping. I thought my turbo was blown until I saw there was oil in the impeller of the turbo, and the valve cover breather lines going into the turbo inlet had oil in them even 2 weeks after took it apart.

I know for a fact my RB20 was filling the valve covers enough to over flow into the turbo inlet.

And this time I put it back together I enlarged the stock head drains and I have two small -6 drains from the head to the oil pan. I'm using the stock restrictors since I couldn't find any in time. And even then, I would have drilled them out a tiny bit.

gawdzilla-Sounds like we have the same problem really, but I was only running 215whp/stock boost, and I only had about 5-8min of drifting time broken up into 3 parts. That's why I think mine is more there's just too much oil in the head or too much suction.

The 3K street miles I never had a problem but in only a few minuets worth of track use and its already burning oil.

~Alex

[gawdzilla]

this is a pretty old thread, but i'll provide my experiences. i think it may have to do partially with your oil weight. also i can definitely say the baffles in the valve cover help. alot.

last month i ran at the track with 1.5 qts of 15-50 to thicken up my normal 10w30. got some blowby in my catch can. about 5-6 oz'es after each session. i'd top off with more 15w50 mainly for temp reasons.

this weekend i ran again (30 minute sessions instead of 20, woot). ran 10w30 with about 1.5 qts of 10w40. almost 0 blowby in my catch can the entire weekend (300+ miles of track, ~2hrs of track driving), never needed to top off my oil at all. maybe the oil i was running was too thick? who knows. my motor seems pretty happy with an oil between 10w30 and 10w40 though.

[marshallpre1]

this is a pretty old thread, but i'll provide my experiences. i think it may have to do partially with your oil weight. also i can definitely say the baffles in the valve cover help. alot.

last month i ran at the track with 1.5 qts of 15-50 to thicken up my normal 10w30. got some blowby in my catch can. about 5-6 oz'es after each session. i'd top off with more 15w50 mainly for temp reasons.

this weekend i ran again (30 minute sessions instead of 20, woot). ran 10w30 with about 1.5 qts of 10w40. almost 0 blowby in my catch can the entire weekend (300+ miles of track, ~2hrs of track driving), never needed to top off my oil at all. maybe the oil i was running was too thick? who knows. my motor seems pretty happy with an oil between 10w30 and 10w40 though.

Bumping this up, what engine do you have? Also, any other oil related mods (ie head drain, restrictor, etc)? Any mods? What kind of tires? I want to do some HPDEs in my 240 but even though it's fully stock right now, I'm scared it may blow up with all these oil "issues"

Thanks,
Jeremy