sr20det excessive oil overflow

[maxwagner]

So I just finished building my sr. cp pistons eagles rods etc etc.
anyway, I had driven the car nice and easy, compression breaking when ever i could, not taking it over 4000 rpm until i put 600 miles on it.
at this point i thought it was okay to do some sliding so I took it out and drifted for about a hour ( in the rain ) and everything seemed perfect.
When i stopped at a gas station i noticed some oil dripping from the cold side of my intercooler. immediately took it off and noticed a small puddle of oil in it.
so instead of routing the oil overflow back to the intake i just put a breather on it. after about a day that breather was soaking wet with oil.
I am completely lost on why i have so much over flow.. any ideas?

[om3ga]

S13 SR? How is your PCV system hooked up? Can you take pictures of your line routing. You can always do an s13.4 valve cover

[maxwagner]

This is almost exactly how I did it. instead of the hose to the breather it is just a breather. with the opposite side routing back to the crank case.
I just did a compression test and it came back 150 on the spot across all 4.

[maxwagner]

I forgot to mention. My vac is at -12 give or take at idle. So i am thinking pcv valve??
but before the engine was built it still idled at around -12. I read on another forum that usually it is supposed to be at -18 to -20??
Thanks for the response.

[Yellow4g63]

Do you run some big aftermarket cams? -12 vacuum seems very low. should be in the 18-22 range if u have stock cams.

[JBPUSA]

Turbo seal gone bad??????

[Mikester]

First thing you did wrong was only run it to 4,000 or less rpm for those first 600mi...

The rings on a fresh rebuild need to be seated for the ENTIRE rpm range. You will get 4,000 and below just by driving it easy in town & on the freeway. However, to seat the rings for the upper rpm ranges, the car needs to be operated in those ranges; and engine-braked just like you did at 4000 and below.

A good rule of thumb is that whatever you do in about the first 15-20hrs of engine life is pretty much all you're going to get for the life of the engine. Therefore if you kept it at 4,000 & below the whole time- That's pretty much the only range of rpm where you won't get excessive blow-by. If it's not too late, you need to work on accel/decel in the upper ranges.

Second- the S13 SR PCV system by default NEEDS the OEM oil/air separator or an aftermarket air/oil separator to operate properly (little ugly black can between valve cover tee fitting & crankcase drain). If you have the crankcase venting installed without it, the IC basically becomes a giant catch can. This is why the little filter on the front of the tee became soaked with oil (fire hazard btw if it drops onto the exhaust manifold)... and why there was a bunch of oil in your IC (in addition to not seating the rings in the upper rpm range)

The setup om3ga posted is 'okay' but it doesn't ensure that there is always vacuum inside the crankcase/valve cover; essentially robbing himself of performance. He'd be much better off losing that little filter & running a tube from his catch can to the turbine inlet piping... However, if you notice, he did the S13/S14 hybrid valve cover, which is awesome; and the design that Nissan SHOULD have went with for S13's in the first place for this very reason.

On the intake side of the engine, the PCV valve is open at idle/cruise providing the vacuum to the crankcase. Under boost, the PCV valve slams shut- and the turbo provides the vacuum... If there isn't an oil/air separator between the tee and the crankcase; or a catch can between the tee and the turbine inlet- A lot oil will be sucked thru the turbine.

My setup is similar to om3ga's, but ensures there is always vacuum to the crankcase-



Given the physics of what I just explained above, I have to empty out the catch can once in a while because I removed the OEM oil/air separator... But better to empty a catch can than to have to empty an FMIC lol...

Other than reintroducing an oil/air separator, the only way to fix it is to do an S13/S14 hybrid valve cover like om3ga posted (but with tube hooked up to inlet for vacuum under boost), or do like post #144 on page 5 of this thread . Since I have no desire for a slanted valve cover, I bought a brand new valve cover and intend to mod it as shown in the post I cited.

Good luck to ya.

--Mike

[RalliartRsX]

Mikster, did you install baffle in that catch can?? When I built mine, I made sure to install stainless steal mesh around the inlet portion (which also had a aerated tube) and went from there.

I have pictures of the custom setup if need be

[RalliartRsX]

Below is how I built mine

How To: Another DIY Catch Can mod - Dual, with baffles and extended inlet tube - evolutionm.net

[Mikester]

Originally Posted by RalliartRsX

Mikster, did you install baffle in that catch can?? When I built mine, I made sure to install stainless steal mesh around the inlet portion (which also had a aerated tube) and went from there.

I have pictures of the custom setup if need be

Appreciated that dude... and no I didn't... Consequently, my can slurps in about 1/2cup of oil every 500mi or so. This is why I'm doing the different fitting placement on the new valve cover I bought. Unfortunately, I wasn't aware that mod existed until I was WAY too deep into the build to dick around with it... so for now, I'm sorta working with what I have lol... Have NO DESIRE to cut into the Kazama can. I was looking at JEGS oil/air separators for maybe an interim measure- but now that winter is about hit hard, I figure redoing the new valve cover will makle a perfect winter project

You should post pics anyway... could help this guy out.

and IIRC, Kyle (Blackzenkis14) had a thread a while back about a company that sells baffled cans; I forgot who they are. Either way, OP NEEDS to either run the car in the upper rpms, or NOT DRIVE IT until he can do so- IF it isn't already too late

[Mikester]

LOL we were posting at the same time haha!

I did that with my can in Okinawa... Did a great job of trapping the oil, but still would fill up every so often. Could very well have been due to where I had it located in the system tho.

[maxwagner]

People say sooooooo many different things about the break in process. Some say do consistent pulls, others say take it easy for 500, etc.
considering i have never broke in a new motor the most reasonable thing was to take it easy.
As for the black oem overflow canister, the after market exhaust manifold takes its place.
Thank you for the input

[RalliartRsX]

..........And that black canister was there for a reason. So you best find a way to substitute something in its place or you will have a never ending uphill battle..........

In order to break in rings, you need to "drive it like you stole it". As mentioned by Mikester (and if you do not believe he is knowledgeable, take a look at his build thread for credibility), you need to expose the rings to the operating conditions they will subjected to the rest of their lives.

In an ideal world, to break in an engine, you place it at a sustained RPM for a set amount of time (depends on final engine use, materials, etc) and do this a multitude of times. Since engine dynos for break in are expensive, then the second best thing is to do it while in the car (meaning "drive it like you stole it")

[Mikester]

Originally Posted by maxwagner

People say sooooooo many different things about the break in process. Some say do consistent pulls, others say take it easy for 500, etc.
considering i have never broke in a new motor the most reasonable thing was to take it easy.
As for the black oem overflow canister, the after market exhaust manifold takes its place.
Thank you for the input

You're welcome. As stated, an exhaust manifold does not replace the oil/air separator- it just gets in the way so people remove it not understanding why it's there... having drained oil out of your IC, I'm confident you now know why it's there. BL: The only things that truly 'replace' the OEM oil/air separator are an aftermarket or relocated oil/air separator; or a modified crankcase ventilation system- hence the link I provided you.

Going back to your methodology with that fresh rebuild... Don't be butthurt- I was trying to help you... Had I not researched that topic in-depth; I may very well have made the same error along with you and many others... Even so, I STILL made my share of errors; long after the motor was together and it was no longer practical to do anything about it... so don't think that I'm out to dog you down- I'm just an enthusiast like you... nothing more. Only difference is that I don't let my feathers get ruffled at the first sign of not hearing what I wanted to hear

BTW- Did you notice that never once did I use the phrase "break-in?" That's because we're not talking about an oldschool V8 where metal parts need to physically wear into one another... Advances in 20th/21st century technology have afforded manufacturers & machinists the ability to economically measure & build to precise tolerances- pretty much eliminating the need to do anything else besides seat the rings. Quite simply, if you run a freshly rebuilt SR up, drain the oil & see metal shavings beyond the powderized remnants of the machining process... you may as well pull it, put it on a stand and tear it back down because something is royally wrong

If you need to know anything else beyond what we tried to explain, then maybe a builder/mechanic/machinist will chime in and really confuse you lol... Plenty of them here. May not want to get snippy with them- They are far less tolerant.

[maxwagner]

hahah I was most certainly not being snippy. Just saying there are a ton of different break in methods. It seems to be a very controversial topic.
Where should i go from here? just continue to run the motor throughout the entire rpm range?
again, thank you.

[fatduece]

Mike, can the tube coming off of the valve cover (right by the fire wall, not the one by the turbo inlet) be routed to the catch can and then run an extra tube from the catch can to the crankcase? That way the catch can drains right back into the crankcase and never has to be emptied out. Thanks!

[Mikester]

Originally Posted by maxwagner

hahah I was most certainly not being snippy. Just saying there are a ton of different break in methods. It seems to be a very controversial topic.
Where should i go from here? just continue to run the motor throughout the entire rpm range?
again, thank you.

Yes, you should do whatever you can to seat the rings in the upper range. Again, I hope it's not too late...

Originally Posted by fatduece

Mike, can the tube coming off of the valve cover (right by the fire wall, not the one by the turbo inlet) be routed to the catch can and then run an extra tube from the catch can to the crankcase? That way the catch can drains right back into the crankcase and never has to be emptied out. Thanks!

You can route them any way you want. The key is that there is always a vacuum (not just a 'vent') on the crankcase. The easiest, most logical way to do it is to use the turbine as the vacuum source under boost, or custom-route one of the catch can hoses into the exhaust stream as a standalone vacuum for the entire system; utilizing the venturi effect.

For me, I'm not a qualified mechanic or fabricator; so I do my very best to use the KISS concept as much as possible