lonely_driver4

im going to be running a high compression 12.5:1 b20v. would it be better to vent from block or valve cover? i dont think both is necessary plus i dont want to do both. id like to do one or the other. what would be a better option for me and why? ive heard the block vent is fine but it fills with oil quickly. put money and labor out of the equation, what one vents better in the all motor world? i will not be running a drain back on my system i will manually drain when needed.

lonely_driver4

bump anyone??

wunfstgsr

You pretty much answered your question..

Not all engines will perform the same.

Do you want the can to fill up and spray oil all over the engine bay or do you want to vent it more evenly.. Cause this can happen venting just the block..

IMO its better to vent the block and head as crank case pressure builds up in both areas. Read my post in the last page of this sticky!


Oil Catch Can Setup for VTEC engines w/o silly -10AN Valve cover Vents - Honda-Tech - Honda Forum Discussion (honda-tech.com)

lonely_driver4

cool, ill read your post on it. with an engine like mine i dont understand why you would have to vent both. the block and head are connected by passages, so couldnt it all vent from one area? i understand its better to have both but i feel i dont need that much ventilation. what's your opinion? if you had to vent from either the block or head what one would it be?

lonely_driver4

not everyone with a catch can vents block and head i feel like a lot of people do one or the other i just want to understand how to make that decision

spAdam

iTrader: (1)

NA engine + street car? Do a closed can off of the back of the block with a good baffle/filtration setup and a PCV valve. Mount the can somewhere where you can drain it from time to time. Cleaner running and still keeps the funk out of your intake tract.

lonely_driver4

i dont want to run a pcv valve. i want a very simple set up. two hoses to a can. i just cant decide weather to vent from block or valve cover. money and time isnt an issue. their is so many ways to build a venting set up.. im so confused. as mentioned above yes it would be ideal to vent both but for my set up i feel venting from one location will be enough and keep it simple. i dont want a drain back i will manually drain when needed. venting from the block seems to fill up with oil as ive read. from my understanding the block and head are connected with oil passages so in my opinion it makes the most sense to vent two -10 lines from the valve cover. am i totally missing something? i know i sound like an idiot but i cant find a solid answer saying what location will do what and what one would be more ideal.

lonely_driver4

i wanted to run it open, just vent to atmosphere

lonely_driver4

ideally, i should vent two off the block and two off the valve cover to one catch can like speed factory offers. if i were to do one or the other what would be the pros and cons of each? personally venting the valve cover seems like the best way as its at the top of the engine, it wouldnt fill with oil and it still allows all the pressure from the block and head to be released...but i wanna hear it from the guys that have been here for ages not some noob like me lol... the b20 from factory does not have any block vents. it vents from the head only. that being said doesnt it make more sense to keep it that way and go from the valve cover? im not opposed to the block if it will properly work meaning vent the whole engine and not fill up every week.

wunfstgsr

You dont your right! lots of factors like engine wear/ condition play a role with how much crank case pressure pushes through the rings and valve seals. If you want to keep it simple and easy to maintain run 2 lines from the valve cover and be done! this way its easy to remove the lines vs having to crawl under the car and wedge your hands to put the lines off and on! its a PITA to get to those 2 back ports especially if you have on those crappy hose clamps! if you use push on hose fittings use OEM hose claps so when removing you can use a angled pair of plyers to remove them. And to make it even easier buy the level 7 oil cap so you dont have to modify your valve cover for fittings.

Its all on the type of driving each car is put under and comes down to personal preference do what works for you then upgrade if you still need better ventilation.

Then i suggest delete the OEM PCV system AKA black box and run 2 lines from VC to a quality catch can.

That's fine and most common but this does affect smog regulations FYI depending on your state.

lonely_driver4

great info, thank you for t he reply!! you also come thru with good knowledge on my posts... if i can safely run two -10 fittings off my valve cover and vent it to a can safely thats what id like to do. just a nice simple set up. i checked out that post you put above. very interesting set up!! im not worried about regulations and all that. my 97 coupe already doesn't pass inspection due to no evap and it being all converted to OBD1... still trying to find a way to pass inspection. i got a guy that will let anything slide as long it it plugs in and no check engine light. im in NYS so they dont check what emissions are coming out of your muffler like alot of states do. its only visual and OBD2 plug in. in a couple years i wont have to worry about any of that tho. once the car is 25 years old its considered a classic and only needs a visual inspection. no plug in BS. due to covid i didnt need an inspection all summer so i got to drive a good bit without inspection lol

wunfstgsr

Nice yea no problem anytime, out here in CA its very strict but i have connects to pass smog, and a few years back maybe 7 years ago a buddy of mine did my smog and somehow left it in a loop, my registration always comes as a renewal so i haven't needed a smog in over 8 years lol i still dont know how he did it he said something about it but i forgot and he had a stroke and is now disabled. im just glad all i need to do is pay for my tags! there's a supermarket that has a DMV kiosk and it makes getting your tags so easy no wait.

lonely_driver4

thats crazy lol ive never heard of a dmv kiosk in a grocery store haha, kinda makes sense in a way. it feels good to cheat the system, cheers haha...

spAdam

iTrader: (1)

You kind of answered your own question... it's that either way will work fine. Honda did it one way on some motors and another way on others. I don't personally think that the valve cover baffling on the B18B/B20 valve covers is that great, but I don't think Honda intended those engines to live at the duty cycle that the VTEC motors live at either.

Two off the block and two off the head is a lot for an NA engine. You just don't have the same amount of blow-by to get rid of as if you had an FI engine. The stock system on the vtec blocks is actually pretty fine for a street car too, but you don't have that so you'll need to plumb something in. The points about doing it from the valve cover to make it easy to disconnect are valid. If you did it from the back of the block with -an adapters, that would also be easy to undo and would look cleaner (in my opinion). Doing both won't do much more than drain your wallet.

That's the rub of using a B20 block. He doesn't have a box to delete, and has no venting at all without adding something since the whole PCV system lives in the valve cover on the stock head.

wunfstgsr

I keep forgetting the B20 has no PCV system like the Vtec engines. I think you pretty much summed it up for the OP and i stand by your points!

lonely_driver4

good info thank you. I think I'm just going to run two -10s off the valve cover to a nice catch can. seems to be the easiest to me. as mentioned above about using a PCV valve and vacuum assist on a street car is that something I should be doing for a street car? if I were to vacuume assist how do I go about doing that? if its unnecessary by all means I don't want to do it. I just want to make sure pressure it getting out correctly and efficiently for my set up.

spAdam

iTrader: (1)

For a street car you really should, yes. It's cleaner and more maintenance free. Most people don't. The idea is that, when you are cruising around at part throttle with manifold vacuum, that you are continually exchanging the air in the crankcase. Manifold vacuum pulls it out, scrubs it through the can, then whatever is left gets burned. As long as you are running a can with baffles and/or a good medium to catch and condensate the water vapor and oil mist, you'll still be fine, there won't be much of anything to pull back in to the manifold if the can is well designed. Fresh air is constantly being pulled through the hose from the intake tube to replace what is being sucked out by the manifold vacuum.

Race cars* spend significantly more time at wot, so they don't get as much of this action and therefore a sealed can is less effective. That's one reason why they tend more to have open systems. They also don't get driven as much, fluids get changed out all the time, and draining a catch can is less of a hassle.

*Wet sump race cars, that is. Dry sump race cars pull significant vacuum on the crankcase and are sealed systems.

If you wanted to do a closed system, there are inline PCV valves available that will work on -6 hose (That's all you should really need for a return). If you are looking for a nice can with good baffling that can be run open or closed, the Radium setup is really nice but not super cheap (you did say you'd like to run a nice can though). They have a PCV valve that works with it too. For either setup, if the can inlet is higher than the block or head outlets, most of the oil mist will fall back in to the engine and the fuel and water vapors will re-condense in the can. There's one advantage to venting from the block. The only other I can think of is that venting from the valve cover will require some welding.

FWIW after all of this, I'm currently running no catch can on a non-vtec B20 with the stock PCV setup due to street legal-ness until I get my BAR sticker. It's not ideal. Prior to that I had an open (vented) can off of the block fittings with push-on hose. I drained it from time to time and it rarely had much in it unless I did an all-day canyon blast. It was not easy to remove for smogging. Next move is the Radium can with their PCV valve running back to the manifold.

lonely_driver4

well ******* said thank you for breaking this down for me. I'll be running an open system to atmosphere. goautoworks has a nice catch can ive been looking at. seems pretty simple design. one filter. two -10 fittings and a drain on bottom ( i will drain manually) so if I were to hook up a vacuum to this set up im explaining would I run a rubber vacuum hose from the intake manifold to the nipple on the valve cover with a pcv in the middle? so cruising along it still pulls vacume to the crank case but wide open it will just vent it all to the catch can? ill draw up a shitty picture to explain

lonely_driver4

i used a picture of my engine bay with a b16a but same concept. does that look like a proper street set up?

lonely_driver4

or would that way still put junk back into my intake manifold? I don't want anything going back in as I am running 12.5:1 on 93 octane and I need to keep detonation to a minimum and I just want to keep it all clean

lonely_driver4

or do you have to run the Radium catch can to put vacuum to the catch can? I just looked them up. looks really legit.

spAdam

iTrader: (1)

Removing the junk is the whole point of the can.

You can do it with just about any can, some will just require more creativity.

spAdam

iTrader: (1)

Wait, are you showing the valve cover nipple connected to the intake manifold here? That would be 100% wrong. The valve cover nipple is an inlet and should be connected to your intake tube, never to a vacuum source. Also, if you are running an open can there is no point in having a PCV valve.

edit: I see what you’re describing there now. Still doesn’t work. Your PCV line would be pulling straight from the valve cover to the manifold and you’ve left no way to get fresh air into the engine. Actually, if you are implying an open catch can there, the system would work in reverse during vacuum.

lonely_driver4

yeah I thought about it and that literally would not make sense sorry for the confusion lol, I dont know why but all of this is kinda confusing to me haha. im just gonna ditch the vacuum and run a catch can. thank you everyone that helped clear up this question for me

spAdam

iTrader: (1)

You’ll still need an inlet to the crankcase.

you can’t get anything OUT to the can unless you can get fresh air IN Easiest way to do that is to have the hose from the valve cover to the intake pipe. The intake pipe always has roughly atmospheric pressure and it’s cool and filtered. That’s why it’s used for that.