Do CA heads flow alot of oil at high RPMs????

[Hillkill]

Does anyone else here have a problem with blowby out the exhaust cam at sustained high rpm? I have a catch can routed in between the exhaust cover vent and the intake piping. But say during one drift run and a decent 30 second burnout I fill my catch can with the 10w40 royal purps. Or if it was say 3 hard drift runs I would have the same outcome. It just sucks to have to let it cool down and then recycle the oil from the catch can just to do the same thing in 3-4 more runs. I'm running stock boost on a s15 spec R with 550's

[anumeric]

Does anyone else here have a problem with blowby out the exhaust cam at sustained high rpm? I have a catch can routed in between the exhaust cover vent and the intake piping. But say during one drift run and a decent 30 second burnout I fill my catch can with the 10w40 royal purps. Or if it was say 3 hard drift runs I would have the same outcome. It just sucks to have to let it cool down and then recycle the oil from the catch can just to do the same thing in 3-4 more runs. I'm running stock boost on a s15 spec R with 550's

I'm in the same boat as well. Sounds just like my car except I'm running a sr t25 7psi with stock injectors. Next build I'll be doing the drainback mod on the head like this one.

[rico05]

I get a little. Like, a teaspoon MAYBE. The other night, I was jacking around out in the country, and I had a tiny bit on my valve cover (I usually run a filter but I had it off).

A whole quart? That is scary man. Me thinks there is more going on. Check your compression to be sure. Also, I was having an odd amount coming out when my exhaust cam was off by a tooth.

[themadscientist]

maybe a restrictor in the passage like RB26s like.http://www.tomei-p.co.jp/_2003....html

[fluent]

the solution posted in the pictures of boot_it's mod has been refuted by niscort.search threads! :p

[boost_boy]

Does anyone else here have a problem with blowby out the exhaust cam at sustained high rpm? I have a catch can routed in between the exhaust cover vent and the intake piping. But say during one drift run and a decent 30 second burnout I fill my catch can with the 10w40 royal purps. Or if it was say 3 hard drift runs I would have the same outcome. It just sucks to have to let it cool down and then recycle the oil from the catch can just to do the same thing in 3-4 more runs. I'm running stock boost on a s15 spec R with 550's

If your engine is spitting-up that much oil, then your bottom end is probably at it's service limit. And even it is a rebuilt engine, your clearances are probably at their limit. I have a customer that have sustained 30psi of boost with 3 people in his car and still haven't put out that much oil. Whereas in my own case, I have run my car hard against various cars over a 100 mile stretch, got two races at the track in which I won both, and repeated the same trek back 100 miles with even more abuse and still didn't reach a quart of spit-up. Bottom line is, your engine is worn and routing the oil from the head is masking the problem. But if you can't afford to rebuild, it is your car and you are entitled to do whatever you think is necessary. Good luck!

Dee

[RS12Turbo]

Hey Eric.......my old "remanufactured" ca18et from Jasper Engines (pure garbage sh*t motor) puked up oil through the breather at high rpms from the time it was brand new. Maybe part of the reason it crapped out with only 12k miles?? My original ca-et with over 200k miles on it never had that problem.

In anycase....my ca-det doesn't do it at all....I've had a catch can on there for 6+ months now....and it is dry

[DALAZ_68]

I'm in the same boat as well. Sounds just like my car except I'm running a sr t25 7psi with stock injectors. Next build I'll be doing the drainback mod on the head like this one.

intresting...were do u run the lines

[themadscientist]

back to the oil pan.

[sydwayz]

fresh rebuild perfect clearances less 2000 miles on the motor and mine spits a quart every pull i make after 5500. took the head back off had a smaller oil restrictor made put that in and still does it. now im installing an evac system on my car this week. I SWEAR ON MY LIFE THAT I WILL SOLVE THIS PROBLEM FOR EVERYONE

[boost_boy]

fresh rebuild perfect clearances less 2000 miles on the motor and mine spits a quart every pull i make after 5500. took the head back off had a smaller oil restrictor made put that in and still does it. now im installing an evac system on my car this week. I SWEAR ON MY LIFE THAT I WILL SOLVE THIS PROBLEM FOR EVERYONE

You've got a problem with something! Even my mitsubishi engine with 120, 90, 90, 120 still doesn't puke-up oil and that's under 15psi of boost and over 7000rpm dumps betweeen 1st, 2nd and 3rd gear. I'm building CA18 #25 for one of our members and I'll be damned after 24 successful builds that this one will be the one that spits-up oil. You say clearances were perfect, but nothing is perfect. Could be the rings you chose, maybe they were put on upside down or your bore specs are out of limit in the lower portion of the cylinders. There's no mystery to this motor. It's either built right or built with issues and your is no exception to the rule as it shouldn't be spitting-up oil if it was just built and everything was within service limits. Bottom line is that something went wrong with the build???????????

Dee

[Hillkill]

I'm not just talking about freeway pulls because It doesn't have excessive blow bye until I bounce off the rev limiter for like 10-20 seconds. Next time some of you guys get a set of tires that need to be killed tell me if you get any blow bye after finishing them off for good. I'm talking many clouds of smoke.

The drainback mod looks interesting???

[r34 gtr]

I will admit that my engine is guilty of spitting a little oil through the breathers after a good donut session. I don't really see a problem, but a quart though? Thats a lot of oil man, and I would like to find a way to make sure that oil made it back to the pan.

[float_6969]

I have a theory, but it's only a theory. Here it goes;

The stock PCV system is flawed to start off with. If the system is altered in any way from factory, it's effectiveness may decrease. Also, the main line for the crankcase gasses to pass from the crankcase to the head is the metal tube that connects to the top of the oil filter mount to the intake side valve cover near the back of the head. Under the intake manifold, Nissan decided to make the tube not only taper down, but also squish flat to clear the starter and intake mani. If that line has any restriction at all, it increases the restriction of crankcase gases to the head. The gases will take the path of least resistance, and if that line gets plugged up, the only other route is the oil drain passages. This can cause oil to pool in the head and with the spinning cams, can begin to vaporize the oil to the extent that it's drawn out of the valve covers in much greater amounts than normal.

My first idea to correct this problem would be to remove that tube that runs from the intake valve cover to the oil filter mount and replace it with the largest diameter oil resistant hose than you can fit. This should allow the gases in the crankcase to easily move to the head and be removed, allowing the oil in the head to properly drain back to the oil drain passages.

The other idea I have is to change how the system works all together, but IDK how to explain it without drawing some sort of picture.

[sydwayz]

so im getting rid of the pcv system all together with the evac system and if this doesnt fix it im going to weld on another nipple to the exhaust side valve cover so that i can tee into the cranckcase gasses hose (i got rid of that pipe like float_6969 says) and run it to the exhaust side valve cover too or at least some how connect the two valve covers together

[r34 gtr]

The other idea I have is to change how the system works all together, but IDK how to explain it without drawing some sort of picture.

Yeah, you need to boot up MS Paint and get busy.

[float_6969]

OK fine...

Click it to make it bigger;

[niscort]

looks like a good working solution.

[r34 gtr]

Think that would really work? I mean, I could have my car set up like that in 15 minutes. I guess it couldn't be any worse than me just routing the breathers directly into the intake manifold. I really like the EVAC system The_Chosen_One is using though.

[sydwayz]

thats what im doing! drag cars have been using that evac system for years and if that doesnt work ill work of that system

[Ca_Silvia]

You have to be running a MAP sensor for that idea to work right Float?

[zmannz]

OK fine...

Click it to make it bigger;

^ I am a little confused about this. So the idea is that all of the gases with blow-by oil that would normally drift up and out of the valve cover vents gets pulled down into the oil pan by vacuum, and then back out and over through a catch can? Seems like you would have more problems of oil staying in the head with this during throttle let-off. If you just unhooked the factory line that sends the crankcase gases to the head, the one you mentioned was undersized and easily damaged, and teed one valve cover line to it together with another line coming off to connect to the other valve cover, with a breather on that cover, then there should be much more air exiting the bottom end ALL of the time. I would love nothing more than to never see oil in the intake side of my engine bay parts again.

[sydwayz]

so i installed the evac system like the chosen one and it SEEMS to have gotten rid of my 1 quart of blow by problem. im gna drive it around today and tune it a lil and really see if it works . i just cant believe that it worked. it cost me about 200 dollars to install this evac system

[float_6969]

You have to be running a MAP sensor for that idea to work right Float?

For that exact setup, yes. You might be able to plumb the valve covers into cold pipe/hot pipe, but IDK if that would pressurize the crankcase or not. I would think that it would.

[float_6969]

In the stock configuration, the only path the gasses have to make it up to the valve covers and out of the motor is via that undersized tube, OR the oil drains. If there is too much gas for the tube OR the tube is obstructed, the gas is going to come UP the oil drain, which SHOULD have oil going DOWN it. This would cause the oil to pool in the head.

With the way that mine is configured fresh air is constantly drawn in from the top of the motor. The only path it has to the crankcase is via the oil drain. The air moves down, and draws the oil down with it. After the air picks up oil, water, and other nasty acids floating around in the crankcase environment, it leaves the crankcase and passes through the catch can, wich separates most of that nastiness from the air. The mostly clean air is then fed back into the motor, so that it can be burned.

[r34 gtr]

I'll set mine up like that when I get my hands back on it. I shall let yallz know how it works.

[float_6969]

Cool, you can be my guniea pig.

[anumeric]

I was looking through some of the catch can setups in the stickies and was thinking about trying this setup CA19DET posted up, except using 2 separate catch cans with breathers for the intake and exhaust sides.



I'm currently running the exhaust side to a catch can w/ breather and the intake side is still plumbed to the PCV like stock. I'm thinking since the PCV closes under boost and blow-by gases are only vented via exhaust side, that going this route would allow both intake and exhaust sides to be vented at all times? Do you guys see any problems with this on a MAF setup? Am I headed in the right direction or just retarded?