[Jdesr]

Hello everyone, first i want to start off with that fact that I am not an expert and i wont pretend to know everything about this car.

I have a 1999 LS integra DC4. Its a b18b1 paired to an S4XA, i bought it a little over a year ago and had the engine rebuilt as well as the transmission. I really enjoy this vehicle and want to keep learning more.

Recently I ordered a mishimoto catch can for the car but ended up returning it because it was too big and I didnt like the quality of the can itself, very cheaply made.
After that I kinda forgot about PCV venting until yesterday I decided to pick up filter breathers and put them on the two PCV vents on the valve cover, they look great. I'm also assuming it is placebo effect but I felt like the car was performing better afterwards.

Later I told my older brother and he stated it "wasnt good for the car" which i was confused about because I thought the whole concept behind installing a PCV catch or breather was so that blow-by vapors which contain oil and vapor wont go into the intake which isnt good for the combustion process. So now I'm more confused, on paper it makes sense to me, why would it be good for these gases to go back into the combustion chamber? It doesnt seem like it would be beneficial in any way but then again i dont know everything.

I want to know if this is good or bad for my engine.

Thank you.

 

[97BlackPearl]

@Jdesr , the PCV system pulls the excess pressurized air out of the crankcase via the baffles in the valve cover. Yes, it's better for the environment to recirculate the oily vapor and cook it in the engine, but that can cause soot to form and cake all over your intake track (from manifold to intake valves to piston--I have photos and they're ugly). That hurts performance, responsiveness, mileage, and idle.

As the engine heats up, all of that heated crankcase air begins to pressurize and needs somewhere to go. Enter the the PCV valve. It's on top of the valve cover and it's basically a check valve--it only lets air flow in one direction--into the intake manifold. When it gets clogged, no air flows and the hot, oil, pressurized air is forced the wrong way back out the breather hose into the intake pipe. This is bad. The hose between the valve cover and the intake pipe (before the throttle) is the breathing side--it normally pulls cooler air into the valve cover to help the oily vapor coalesce inside on the metal baffles and drain back into the head. It can reverse flow under high load when the intake is pulling from both hoses. Check with the Googler to find the thread where a guy hooked up vacuum gauges to see how it all worked (might've been a different Honda site).

A oil breather or oil catch can or drainback system all aim to catch oily vapor that has escaped past the valve cover's baffles before it fouls the intake track. They are basically different varieties of metal can with metal baffles that work under lower temperature and velocity than the small hoses carrying the vacuumed air. It give the oil a second chance to condense out of the air before the intake vacuum pulls it in. Think of it like a cold can of Coke outside on a hot day...it starts sweating...but that's just the humidity in the air condensing on the colder surface. Same idea. This is not a performance upgrade, but rather an engine maintenance item. Coming from someone who has dissected two engines (Honda B18B1 and Subaru EJ25) and cleaned the soot out of them in the last 6 months--either get a catch can or have a machine shop replace your piston rings (blow by is what causes the oily vapor in the first place). Pulling the fuel pump fuse/relay, removing all 4 spark plugs, and doing a compression test will give you an idea if your piston rings are worn. It's a free rental from O'Reilly Autoparts.

In any case, the silly eBayesc screw-on PCV filters that were so popular back in 02-05 (when we didn't know any better) haven't helped anyone. Using these filters defeats the vacuum which Honda designed the crankcase for--with less air to push out of the way, the pistons can more more freely.

Changing the oil religiously to prevent piston ring wear and blow by is your first line of defense. If that opportunity has come and past, replace your PCV hoses, valve, and grommet(s) and then get an oil catch can (connected between PVC valve and intake manifold vacuum port) and remember to drain it every week or two. If you don't feel like maintaining the oil catch can, get a drainback system like the stock Honda 98-01 GSR breather or a Crawford drainback system. I still have to pony up $300 for a Crawford so in the meantime, I have to weekly Seafoam (1/2 pint) and 93 octane gasoline (prevents early detonation/knock) in my wife's Subaru. It has some pretty bad piston ring wear (145 psi when she should have 175) which is actually normal for a boxer engine, but hateful to someone who has to maintain it.

 

[Jdesr]

Dude thanks so much, this all makes so much more sense. I was also really confused as to why the valve cover had two ports in it going to the intake tract. But you answered that too. I think I'll probably just get a better quality catch can and install it correctly. This is great man so much useful information thank you for taking the time to write all this up. Im going to save it. for future reference.

 

[97BlackPearl]

You're welcome.

Before reluctantly settling on the wildly overpriced Crawford drainback system, some catch cans I initially looked at for the Subaru were Perrin and Cusco. I don't think that the can specifically matters as long as it's installed away from the engine/ exhaust, it must have some decent internal baffle system, and the new vacuum hose inside diameter needs to match what you've already got. Whatever you get, make sure you install it in an easy to reach space. If you can't fit a cup under it to drain it out, get one with a drain hole and install a ball valve with a hose barb on it so you can collect it (e.g. SupplyHouse.com for specialty valves, or Amazon/Fumoto if you have a match for the thread pattern). Fumoto valves are literally made for draining oil.

Don't forget about replacing the PCV valve. Alternately, you can also clean it with copious amounts of brake cleaner if it's not cracked and still "jiggles" when you shake it. Also, if it whistles when it's in the car, it's toast. I replace mine every other major fluid change (every 6 years). The Honda manual says to apply 10-14 psi pressure (NOT more than 14) from an air hose to the valve to check it. If it's completely clean, you can also blow into it like a balloon and accomplish the same test. Air should only pass in one direction (towards intake manifold). If the PVC hoses or grommet feel hard, crusty, or too squishy...replace them. If they're still good, clean them thoroughly with soapy water, then wipe them with CRC Silicone spray. Silicone makes rubber last longer--a lot longer and it makes the hoses look a darker, glossier black.

 

[Jdesr]

Awesome. Yeah im going to get a can with a baffle, filter, and drain plug. Im gonna mount it on the right of the car if you're looking at the bay from the front.

 

[Skiss0r]

@Jdesr , the PCV system pulls the excess pressurized air out of the crankcase via the baffles in the valve cover. Yes, it's better for the environment to recirculate the oily vapor and cook it in the engine, but that can cause soot to form and cake all over your intake track (from manifold to intake valves to piston--I have photos and they're ugly). That hurts performance, responsiveness, mileage, and idle.

As the engine heats up, all of that heated crankcase air begins to pressurize and needs somewhere to go. Enter the the PCV valve. It's on top of the valve cover and it's basically a check valve--it only lets air flow in one direction--into the intake manifold. When it gets clogged, no air flows and the hot, oil, pressurized air is forced the wrong way back out the breather hose into the intake pipe. This is bad. The hose between the valve cover and the intake pipe (before the throttle) is the breathing side--it normally pulls cooler air into the valve cover to help the oily vapor coalesce inside on the metal baffles and drain back into the head. It can reverse flow under high load when the intake is pulling from both hoses. Check with the Googler to find the thread where a guy hooked up vacuum gauges to see how it all worked (might've been a different Honda site).

A oil breather or oil catch can or drainback system all aim to catch oily vapor that has escaped past the valve cover's baffles before it fouls the intake track. They are basically different varieties of metal can with metal baffles that work under lower temperature and velocity than the small hoses carrying the vacuumed air. It give the oil a second chance to condense out of the air before the intake vacuum pulls it in. Think of it like a cold can of Coke outside on a hot day...it starts sweating...but that's just the humidity in the air condensing on the colder surface. Same idea. This is not a performance upgrade, but rather an engine maintenance item. Coming from someone who has dissected two engines (Honda B18B1 and Subaru EJ25) and cleaned the soot out of them in the last 6 months--either get a catch can or have a machine shop replace your piston rings (blow by is what causes the oily vapor in the first place). Pulling the fuel pump fuse/relay, removing all 4 spark plugs, and doing a compression test will give you an idea if your piston rings are worn. It's a free rental from O'Reilly Autoparts.

In any case, the silly eBayesc screw-on PCV filters that were so popular back in 02-05 (when we didn't know any better) haven't helped anyone. Using these filters defeats the vacuum which Honda designed the crankcase for--with less air to push out of the way, the pistons can more more freely.

Changing the oil religiously to prevent piston ring wear and blow by is your first line of defense. If that opportunity has come and past, replace your PCV hoses, valve, and grommet(s) and then get an oil catch can (connected between PVC valve and intake manifold vacuum port) and remember to drain it every week or two. If you don't feel like maintaining the oil catch can, get a drainback system like the stock Honda 98-01 GSR breather or a Crawford drainback system. I still have to pony up $300 for a Crawford so in the meantime, I have to weekly Seafoam (1/2 pint) and 93 octane gasoline (prevents early detonation/knock) in my wife's Subaru. It has some pretty bad piston ring wear (145 psi when she should have 175) which is actually normal for a boxer engine, but hateful to someone who has to maintain it.

Have seen the Project Imports catch can? it looks like their setup deletes the PCV and hoses to the intake completely. It may be an option depending on smog regs in your state.

 

[Jdesr]

Have seen the Project Imports catch can? it looks like their setup deletes the PCV and hoses to the intake completely. It may be an option depending on smog regs in your state.

Thats pretty cool, not sure if it would be legal in CA though. I wanted to get a high flow CAT but CA said no no no. Been thinking about getting some crower cams too but i've heard it might make the car fail emissions. Not sure how all that works though.

 

[97BlackPearl]

You need the hose to the intake manifold. It's what pulls to keep the crankcase under vacuum. If there's less air behind the piston, it doesn't have to work as hard on an expansion stroke. Leaving the pressurized air in the crankcase and forcing it to push its way out of the silly filter (it's silly if it's on the valve cover OR if it's on a catch can), will make the engine work harder. The NSX, ITR, and GSR were the pinnacles of Honda/Acura engineering at the time they came out. Do ant of them have silly filters attached to their valve covers or hoses? No. The GSR & Type-R have drainback breathers (#1) which is like an oil catch can, but better b/c you never have to drain it.

... and the NSX just had a regular PCV system just like the GS/LS/RS (#7 & 8 second image).

--
Remember gentlemen: Keep it Nice. Not Rice.

 

[Jdesr]

Thats pretty cool, diagrams are always super helpful. Where did you find these pictures?

 

[Jdesr]

Oh also another question, would anyone know where i could source a GSR tranny for the b18b1 with ECU? I've been really thinking about converting my car to manual because although I havent found any solid numbers or anything it seems pretty agreed upon that the automatic transmissions are unstable if you start adding power

 

[97BlackPearl]

automatic transmissions are unstable if you start adding power

That's kind of true, but doesn't become an issue until you exceed 250 HP...which (in all fairness) you probably won't. If you've really got the need for speed, find a reputable JDM importer and just buy a complete B18C5 type-R engine and transmission from Japan ($800-1500). I've heard that their low milage engines are so plentiful because they have a crazy emissions law that says the engine must be replaced at 50k. You'll get the chance to mount it on an engine stand and work on it at your leisure until it's ready to swap. You can keep on driving the stock LS in the meantime. Possibly the worst thing you could do would be to buy into the eBay marketing wank that any of the junk they sell will add HP. Think about this: have you ever seen legit dyno test results on eBay junk? I haven't.

Alternatives to a Type-R setup would be an H22/23 setup or a K-swap. There's a lot of threads on here for how to do that and what brackets, hoses, etc. you need to make it work. If I every pull the old workhorse apart, it'll probably be for a newer K-series and I'll stick with automatic because I'm lazy and because newer autos shift faster than human hands can.