I posted this update in my build thread but ill copy it here for relevance.


.... In other news I drained my 1qt catch can after modding the blow by pick up valve port to add the larger hose.

I ran about 15 laps, 12 of those at full tilt session speeds. I checked the can level and added oil to the motor when needed but purposely did not empty the catch can all weekend.

Drumroll


Almost exactly 12 Oz of blow-by accumulated FOR THE WHOLE DAY. That is only 0.375 of the catch can capacity. This is orders of magnitude better than before I modded the separator box air outlet (same motor, same oil). Before I would be emptying the RR can after each session OR the new 1qt catch can would be half full after 4-5 hard laps.



I'm happy with this outcome, It means I don't have to mess around with it until I do my post track day maintenance when i'm back in my garage.

 

"I have come to the conclusion that its not so much the check valve as the air velocity drawing the oil up the rather tiny hose. Think of drinking water out of a normal straw vs a garden hose. The slower moving air of the increased volume will have less energy to carry the liquid oil up the hose to the can. The idea is to more volume available to allow vapor to escape at a lower velocity. I have dealt with crank case blow by road racing Honda's for years and this same idea is how we solve the problem. This stock system with the stock PVC valve and weido hose size is really not ideal in this situation and in my opinion was a sort of a packaging compromise on the Yahama and Lexus side."

Taking your quote above^^^you think this was a design error/compromise from the engineers? That would make sense as they probably weighed how many ISF owners would potentially track their cars the majority of the time as opposed to street driven.

 

Yeah. Most likely. Once they had that metric they then had to figured out how to come up with a solution for those that do inside the packaging constraints of the motor. The solution they settled on is certainly not ideal but stayed inside their design parameters. If you are curious this is what the inside of the separator box looks like.







Its pretty shocking to see how dirty they inside of the box was. this is due to the slip fit design of the attachment points to the motor. Mine were gunked up with grime around the slip tubes from the oil that collects around them. The oil going back into the intake from the check valve is passing through unfiltered into the head and combustion chambers potentially carrying this grime.. No wonder so many people have blocked check valves.. At the very least they should have come up with a better connection method of the separator box.

 

Interesting! What do you think of the internal separator? Did Honda build something like this for separating the oil from the PCV stream going back into the motor?

 

In the earlier motors like the B series there was a convoluted black box and vacuum set up. The very first thing you do is get rid of all this and vent the pressure to atmosphere. In 2000 with the first K series Honda figured it out and ditched the black box on the back of the block. They designed a baffle into the valve cover that has a 180* channel and vents at the highest point. This has a simple tube that connects back into the intake stock. You can easily block the intake connection reroute the blow by vapor into a catch can. Super simple and effective, My old racecar pictured had run 15+ 24hour races set up exactly like this.





The older motors are a bit more involved to fix but the same principals apply. The problem with the ISF IMO is the separator box low placement itself and insufficient baffling. You could build a system to fix this and ditch the oem plastic box altogether. I worked one out where the rear slip fit fitting tube would pipe directly into a baffled collector box that sits up around the battery location. This collector box has a tube that drains back into the slip fit on the front of the block. The collector box is then vented to atmosphere on the other side of baffles built into the box. After doing this you've moved everything up, and added volume and baffling. Once done, you can then block off the tube going into the intake manifold and remove the black box with the check valve and all and not worry about CEL due to air leaks. Pretty simple. Im actually wondering of that is what Lexus is doing on the CCSR. I have only seen pictures of the bays and have not had a chance to poke around one. There is a curiously similar looking box as i have described in that same location that is not anything to do with the coolant system.

 

Fascinating! Thanks for the insight​​​​​​​........I know Lobux was curious about the CCSR as well ^^^as he stated earlier in this thread? Makes sense though

 

@lobuxracer @illwillem

The IS F CCS-R ran the stock PCV valve and hose line intact..

It also went through an RC F motor swap in Spring 2013 (factory backed) in preparation for the Pikes Peak Hill climb that year and testing out the new motor in a "race" environment including 25 hrs of Thunderhill Raceway

The catch can on the CCS-R was simply routed to the 2 valve cover breather hoses instead.. Leaving the PCV valve and separator box untouched..


Here is is a picture of the oil catch can and radiator overflow relocated. As also seen above.







Joe Z

 

So it appears the factory was not concerned about the volume of fluids coming from the crankcase (which have yet to be conclusively identified as oil), and ran their original design separator with no actual modifications. I can see this working fine for Pike's Peak. Not so sure they use the same approach on the 24 hours at Thunderhill. That's the car setup I'd like to see in detail to understand how they managed crankcase effluents.

Also confused why domestics in the circle track arena seem to not have these issues at all. It doesn't make any sense to me why this problem would not be universal.

 

That CCS-R set up is very, VERY strange. There is really no reason to put an accumulator tank at the other side of those VC hoses. I remember seeing a diagram in the FSM (that i looked for for an hour tonight but could not find to post here.) It shows a representation of a cut away of the intake system and engine block with black arrows showing the direction of airflow it uses for crank case ventilation. The two hoses off of the valve covers are indicated to be air 'intakes' with the black arrows pointing the air flow direction as down into the valve covers and following the path through the crank case then into the separator box. Ill keep looking.

 

@illwillem this one ??

 

YES! for the love of god i was going crazy trying to find that. Joe you are a hero for posting that.

Now i wish someone could explain to me why the CSSR has a breather box feeding ambient air pressure into the valve covers. It makes no sense based on that illustration.

Here is a rough phone sketch of a true separator box that would get rid of the OEM set up and solve all the blow by problems by venting to atmosphere and draining liquid accumulation back to the pan or dead ending it with a valve if so desired. If I even do a motor out I am going to for sure build this system. In the meanwhile my expanded volume hose, catch can and relocated check valve will do.