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crankcase evacuation system (CA18DET)

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hi

 

I just did a research (quite huge) on this topic, what crankcase ventilation setup to use on modded car (if any if goin up to 280HP )...

 

so my understandin after reading of it all is that the basic point of it is to create VACUUM inside the oil sumpwhich sucks out the fumes, fuel, water condensation or anythin else that is left by movement of the pistons... thus decreasing possibility of positive pressure buildup (which will slow down oil drainage etc...

 

OK.. I have seen a lot of non-sense setups from people running these cars and claiming that they made the PCV better etc.. (most of them apparently didnt and unless this is done really properly, then its better to leave it OEM...

 

anyway, thing that is quite rare and interesting is some kind of Exhaust Evacuation System - discussed a little here http://nissansilvia....1 ... product like that seen here http://www.moroso.co...p?catcode=13023

 

the basic of it is that instead of connecting the PCV hoses to the back of the plenum and hose to the intake (behind the filter) , you would connect those ends to the exhaust -> which causing vacuum and suckin off all of the mess of your engine crankcase....

 

my question is, anybody ever applied on CA18DET? its mostly used on V8 setups...

 

also, I read some topic on nicoclub - and sombody was mentioning ditching the connecting hose from the 90°bend crankcase pipe (that famous one on the intake side below plenum) which goes to the bottom rear of the intake rocekr cover... and instead, running a hose from there tight into this evacuation setup - so u basicaly bypass the rocker cover ventilation on the intake side....

 

 

any opinions very appreciated..

Edited by this.one

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Pretty sure xris does on his ca

Your rang??? :lol:

 

yes im running a morosso crank case evacuation system on our ca18.

 

Ive got the pipe connecting from above the oil filter to rocker cover. then both rocker cover outputs to a catch can then one outlet to the dump pipe (evac system) and one pipe to the intake pipe

 

Reason why i went this is because we stopped using a PCV valve on the custom intake pipe. so by using the evac system were pulling all the pressurisation out of the head so we dont get oil starvation, also get better sealing rings etc etc.

 

The only pieces of the kit we used were the following

 

140.jpg We welded this into the dump pipe (pretty much where the o2 sensor would go). and welded a -10 fitting to this piece at the bottom555-52211.jpg .

 

Belows a pic of how it looks.

 

558485_10150797367807539_737674426_n.jpg

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yeah seems like the only problem with it is when u have exhaust with cat - then u must route it behind it... and yet, moroso web metions that this system is not ideal for cars with muffler..:D although after readin some forums, this works if fitted corectly (the 45°angle downstream blablabala... :D

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Pretty sure xris does on his ca

Your rang??? :lol:

 

yes im running a morosso crank case evacuation system on our ca18.

 

Ive got the pipe connecting from above the oil filter to rocker cover. then both rocker cover outputs to a catch can then one outlet to the dump pipe (evac system) and one pipe to the intake pipe

 

 

 

Belows a pic of how it looks.

 

>n.jpg

 

 

Is it essential to have a line running to the inlet side?

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Pretty sure xris does on his ca

Your rang??? :lol:

 

yes im running a morosso crank case evacuation system on our ca18.

 

Ive got the pipe connecting from above the oil filter to rocker cover. then both rocker cover outputs to a catch can then one outlet to the dump pipe (evac system) and one pipe to the intake pipe

 

 

 

Belows a pic of how it looks.

 

558485_10150797367807539_737674426_n.jpg

 

 

Is it essential to have a line running to the inlet side?

 

probably not but better safe than sorry.

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hmmm:) and whats inside that catch can ?? to separate the oil from air..???:)

 

also - do you get any differencies in exhaust note? or smell of oil burning? smoke?

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Internal baffles or steel wool

 

I know either of is used, but was curious about his setup :D :D

Edited by this.one

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My bad :-)

 

So on a s13 this set up could be utilized , would it be safe to block off the small breather on the drivers side of the rocker cover and only run the lines off the turbo side?

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I would not remove the breather on the inlet side at the back of the rocker cover infact i would increase the size.

 

When setting up the breathing system on an engine you need to think about what is going on, what are you trying to achieve and where do you need to concentrate your efforts.

 

If you think about where the pressure is created in the engine then you will realise that there are two main areas, windage and blowby. Both of these are are created in the crank case, and crank case pressure as i'm sure you know, robs power, decrease the rings ability to seal and (the main issue with our engines) reduces the efficency of the oil drainage system leading the head being full of oil and the sump not so. The reduced drainage efficency is caused by blow by gases using the head drains as an escape path. So in the drain tubes you get oil trying to go down the tubes to the sump like it's supposed to, but you have gas trying to go up the tube; and since you have gravity forcing the oil and up to 14 psi forcing the gas you can see which one wins.

 

On CA's however there is the breather running from the crank case to the head on the intake side, that is there to allow the gas to escape to the head and in effect try to balance the pressure difference between the head and the sump. The issue with this breather tube on the CA's as it is not big enough (espically with old tired engines that breath a lot and whos tubes are clogged up with tar). The tube starts off a decent size at around -12 but by the time its up at the head it's been dropped down to -6.

I have tapped the fitting on the block with the engine that i'm currently building and have found that the hole in the block with the pressed in fitting removed is -16. This size will not fit up at the head but if i was running an engine for the street i would weld a -10 or preferabbly a -12 fitting the the inlet rockercover. I would then run 2x-10 hoses to a catch can and from there it's up to you but i prefer to vent to the atmosphere but it's fround upon by the popo (or use Neils 'xris' system).

 

For a track engine (this is the system that i'm gong to setup) i would send the cranks case gases (the crack case hose) straight to their own catch can and not send them back through the head. They are only sent to the head in the first place to drop velocity and oil before being sent to the intake to be burnt up, which is for emission reasons. I will then either run 2x-10 hoses from the head to a catch can or seal the head up and lift the size of the hose from the block to -16.

Edited by D_Stirls

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What would you recommend in my instance then?

 

I have the intake side plumbed as per factory and the exhaust side connected to a baffled catch can which is vented to atmo.

 

When I say recommend I mean with the least modification of the existing setup. My balance tube is cleaned out.

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This is interesting stuff..

 

As far as i know my CA's setup on the intake side is stock, but on the exhaust side i have the ventilation hose from the rocker cover going to the intake piping in front of the turbo..

Does having this hose in front of the turbo assist with sucking out this pressure? Or is there something i'm missing here which could be robbing me of power.

 

Recently the stock elbow on the rocker cover on the exhaust side got blown out and was dangling down near the turbo, im guessing a fair bit of pressure would have been needed to cause that ?

 

Xris, interested to know more detail about your CA's ventilation setup if you dont mind attaching more photos or details about it

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What would you recommend in my instance then?

 

I have the intake side plumbed as per factory and the exhaust side connected to a baffled catch can which is vented to atmo.

 

When I say recommend I mean with the least modification of the existing setup. My balance tube is cleaned out.

I did manage with my old engine in the engine in ethe engine bay but it wasn'r easy and i have a pit in my garage.

What i did in that switch was step the size up as big as i could with silicone hose but the issue is still that the fitting in the cam covers is still -6, so you don't really gain any advantage. If you want to take your cam cover off and weld on a -10 fitting then you could gain some advantage by stepping the size up to -10 the whole way through. Or if your not bothered about legalities then do what i am doing and run a big -12 or -16 hose to a seperate can and do away with the hose to the head, be tricky to do with the engine in the engine bay though.

 

 

As far as i know my CA's setup on the intake side is stock, but on the exhaust side i have the ventilation hose from the rocker cover going to the intake piping in front of the turbo..

 

Does having this hose in front of the turbo assist with sucking out this pressure? Or is there something i'm missing here which could be robbing me of power.

 

That's correct, the idea with having the hose on the intake is to draw out the gas and clear the crank case of vapours, it is also why it runs to the rear of the plenum with the PCV because when you are running under vacuum the greatest suction can be achieved. If you have seen the rear two runners in an intake on an old engine you will also see why it's not the best idea with a performance engine as they are caoted with oily sludge.

 

Also oil vapour effectively reduces your knock threashold so if you are pushing your engine to egde with your tune would will make slightly less power with a plumbed back breather system, depending on the health of your engine. The only reason they were plumbed back in the factory was due to emissions, in particular unburnt hydrocarbon emissions.

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Any benefit in me plumbing either port on the intake side into my current catch setup?

Edited by ActionDan

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ok this is really different to the setup on my ca dedicated track car..

 

how would this be for an option?

 

could you simply run the 2 hoses from the rocker covers and also T the turbo oil return line (from the turbo to the sump) all to the bottom of a catch can?

 

also to mount the catch can nice and high in the engine bay so the oil buildup in the can can drain back into the engine once you are off the limiter again. the top of the oil catch can could just vent to atmosphere (or to the exhaust / intake if your after the vacuum affect).

 

i reckon my current shit can setup would be starving my bottom end of oil to. the pcv is blocked and the 2 rocker hoses run directly to the oil catch can.

 

not sure where this hose is that goes from the block to the head

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just went out and had a look is the hose between the head and the block joined at the back of the left rocker cover on the intake side? what an arse hole of a spot!!

 

might block the rocker cover inlet there and run that hose to my catch can as well if thats the case

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Seen that before but never made a call on a good move.

 

I'm thinking of blocking the PCV and teeing the intake side rocker into the catch can via the same pipe that carries the exhaust side rocker. The other port on the catch can goes to an atmo filter.

 

I do NOT have my can plumbed back into the turbo inlet pipe, with a GT2560 on 16-17psi I found it was actually drawing a ton of oil into the can.

 

Thoughts?

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Alloy baffle cut to fit from top to bottom, with swiss cheese holes drilled in it, and some steel wool.

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The only thing that goes into my catch can is vapour which it traps. never had any oil (due to it being a new engine). Cars going back on the dyno in the next week or so to get finished off finally.

 

When you buy the kit you get enough for 2 cars just to let you know. also the bit that screws into the whistle is a 1 way valve.

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ah ok great thank you for info.. btw I read something more on honda forum, they did some research with this and it really looks like its the best solution for gettin the pressureoutta the crankcase...

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and one more thing - very nice proof of it bein actualy realy workin even on idle...

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In Xris setup above, 2 questions.

 

Do you need the pipe from the can to the turbo intake pipe? Is there a valve in there or something that stops it drawing clean air out of the pipe under load as the exhaust valve generates vacuum in the can?

 

Could you run the Moroso valve with connections to both rocker covers but nothing else or does the engine specifically need a place to draw clean air from? If so, can the can have a filter on it instead of a connection to the turbo intake? Although in that instance wouldn't it just suck in clean air under load?

 

Moroso valve aside, is it acceptable to block my pcv, connect the intake and exhaust rockers to an atmo venting baffled can?

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In Xris setup above, 2 questions.

 

Do you need the pipe from the can to the turbo intake pipe? Is there a valve in there or something that stops it drawing clean air out of the pipe under load as the exhaust valve generates vacuum in the can?

 

Could you run the Moroso valve with connections to both rocker covers but nothing else or does the engine specifically need a place to draw clean air from? If so, can the can have a filter on it instead of a connection to the turbo intake? Although in that instance wouldn't it just suck in clean air under load?

 

Moroso valve aside, is it acceptable to block my pcv, connect the intake and exhaust rockers to an atmo venting baffled can?

Both the evac system in the exhaust and the intake pipe both create suction. so both will draw air from the catch can.

 

if you block your pcv (factory suction valve) and run a catch can (which can only rely on gasses/liquid to be pushed out not sucked) your going to make the pressure in your crank case worse..how can a catch can draw air. its the exhaust gases passing the whistle/pcv that creates a suction, no suction no draw = pressure build up = bad for the bottom end...

 

pretty simple. either leave it stock. and run a catch can that uses the intake to draw air out of the rocker covers, or remove and replace with a crank case evac system. (either morosso or a air pump).

 

If i had a stock ca, id run the factory pcv, as standard. and on the other side id remove the hose that goes from the rocker cover to the intake and put a catch can inline.

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