420A Excessive crankcase pressure under boost

[silvreclips]

I have similar issues with oil getting dumped into the catch can under boost. Normal driving mine doesn't have an issue, but after a few autox events mine has almost a cup of oil in it.

 

[rEclipserGST]

Here are some photos from my dual catchcan setup.

I have the factory pcv in place, WITH an aftermarket checkvavle behind it before the line hits the intake manifold.

The intake pipe is used for vacuum and is tied into my boost controller as well.

 

[dustyboner]

Here are some photos from my dual catchcan setup.
I have the factory pcv in place, WITH an aftermarket checkvavle behind it before the line hits the intake manifold.
The intake pipe is used for vacuum and is tied into my boost controller as well.

Now thats the way to do it.

 

[Brad Bell]

I'll try adding some filler. It also crossed my mind that the catch can is lower in proportion to the valve cover. Would this by chance cause the can to fill up quicker? Im working on getting a fitting attached to my intake pipe as well for vacuum.

I need to get a compression test done as well. I really don't think my rings are too bad because I've never seen any smoke from the exhaust and the oil level stays constant, but who knows.

 

[dustyboner]

on my homie's honda, he had it set up like yours originally. with the breather filter on the VC. The car would go thru a f***load of oil when going heavy on the boost, i mean time wise not pressure (only 9psi).
After i got a CCan hooked up for him, with one line off the intake tube and the other to the VC, it stopped loosing oil.

I would think it would be the same for your car. The only thing really different is the size of the fitting on the valve cover. On the honda it was at least 1/2" maybe 5/8". Your is nowhere close to that size.

If your filter has a solid top, you can drill a hole in it, stick a fitting in it and epoxy it in place. It would be easier to route the line going to the catch can cause it'd be a straight shot.

lt would kinda look like this.

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[Blinkyblinx9]

Your crank case should never see pressure from your manifold. IMO you have two options if you have not already done this.

1. Tap your valve cover and run a line from the valve cover to your intake before the turbo (catch can if your preference but not required). You'll then need to place a check valve (and catch can if you prefer) in the line between the valve cover and manifold to prevent boost pressure from flowing back into the valve cover and blowing oil through the new line into your intake.

2. Alternatively and less invasively you can T off the line as close to the PCV port in your valve cover as possible. Run one line to the manifold as before with a check valve to prevent boost pressure from leaking through and one to your intake before your turbo. Optionally you can run a single catch can either off the valve cover (avoid if you can to keep that section of hose as short as possible) or off one or both Td off sections of vacuum line.

Please make sure you get appropriately sized check valves that can handle the boost pressure your running. The nipples can often be a point of restriction in a likely already small vacuum line. Most that can hold a near perfect vacuum are good enough unless your running over 18PSI then you'll likely want something specifically rated for pressure and not vacuum. Best of luck to you.

 

[Macgyver'sDSM]

Installation of filter media inside the catch can gives the vapor droplets something to hit and condense causing them to fall out of the air and accumulate at the bottom of the catch can. Adding a vacuum line to your intake will only eliminate any steam or smoke coming from the filter on the catch can. The only way I can see you reducing the amount of oil in the blowby would be to vent your crank case at the block. The blowby is rushing from the crank case up through the oil return passages in the head then out the fittings on the valve cover. If you can let the pressure out of the block you get less oil in the air only because it is not picking up the oil running down the oil returns in the head. To reduce the blowby you probably need new rings and a hone and or valve guide seals.

 

[Brad Bell]

Installation of filter media inside the catch can gives the vapor droplets something to hit and condense causing them to fall out of the air and accumulate at the bottom of the catch can. Adding a vacuum line to your intake will only eliminate any steam or smoke coming from the filter on the catch can. The only way I can see you reducing the amount of oil in the blowby would be to vent your crank case at the block. The blowby is rushing from the crank case up through the oil return passages in the head then out the fittings on the valve cover. If you can let the pressure out of the block you get less oil in the air only because it is not picking up the oil running down the oil returns in the head. To reduce the blowby you probably need new rings and a hone and or valve guide seals.

This video is a good example as to why I should connect my CC to the intake.

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[Brad Bell]

So I wanted to test what would happen if I drove around without boost, staying in vacuum on boost gauge. Somehow my catch can is still getting some oil into it, even when I baby the car. Starting to think maybe the height of my can is a problem, right out of the line on the valve cover it's a downhill stream to the can. Not allowing oil to potentially flow back. Although I have no idea where to mount my can without doing a battery relocate .

 

[dustyboner]

i think its because even on a stock 420a setup, it has a line from the intake tube to the valve cover. so even without boost the PCV system isn't operating properly. Height doesn't have anything to do with it since its vapor traveling thru the line to the catch can. If the oil was in liquid form it could have a siphoning effect.

 

[Blinkyblinx9]

Well if your not getting into boost at all the catch can should have air going through it on the opposite direction. The hose not connected to the manifold of a boosted PCV system flows in both directions. It pulls in as the manifold pulls vacuum on the crank case and vents outward as the valve is pushed closed under boost and pressure builds up in the crank case. I see no reason why there should be any oil building up in your catch can under vacuum if there isn't some other reason for the pressure to build up in your crank case that would flow faster than your manifold can pull through the valve and the only thing I could think of that would cause that is some serious blow by. Are you having any performance issues? A rough idle? Have you done a compression test? What do your spark plugs look like? All simple things that can help to rule out leaky piston rings that aren't invasive. Keep in mind that everything looking normal doesnt mean it's not blow by only that it's not quite as likely. Also if it is a bit of blow by then coming anywhere close to 0 vac/boost will push the gas into your catch can and if your getting a lot of oil that way perhaps you should consider if your valve cover is baffled or not. They use baffles to try and keel oil from getting to the fittings in the valve cover. Idk if the 420A has any from the factory. Just a thought.

 

[Brad Bell]

I have not done a compression test, but I'm in the market looking for one currently. Car runs great, zero smoke out of the exhaust, -20inhg of vacuum at idle. Idle is smooth and doesn't jump around. Pulled the plugs and they are all dry with a tint of gold color. I'll do a compression test next week and post results. That will tell me for sure if I need to a rebuild this winter :/

 

[Brad Bell]

Alright ladies and gentlemen I have results from the compression test. Take note these numbers were taken from the engine that was running about two hours before the test. Also add that I am running low compression 8.5:1 JE pistons.

Dry Test:
Cylinder 1 - 175
Cylinder 2 - 168
Cylinder 3 - 180
Cylinder 4 - 170

Wet Test:
Cylinder 1 - 210
Cylinder 2 - 210
Cylinder 3 - 210
Cylinder 4 - 200

I am not sure if these are good or bad exactly, or am I sure that the compression ratio of the pistons matter. I am also getting my new intake with fitting for vacuum welded up tomorrow.

 

[dustyboner]

standard value is 170-225 psi (w/ 9.6:1 CR)
max difference between cylinders is 25%

 

[Brad Bell]

standard value is 178 psi (w/ 9.6:1 CR)
max difference between cylinders is 14 psi

So would you say my results are good?

 

[dustyboner]

sorry i posted 4g63 specs, i edited it to the 420a specs.

i have an engine with the same internals and i know i have the numbers from the last compression test written down some where, hopefully i can find them.

 

[Brad Bell]

Okay I got my new intake setup with a port connected to the catch can outlet for vacuum. Did a few hard pulls and still no luck, can fills up about a half inch. I'm really stumped now, I really don't know what other options I have. It's strange cause it used to be totally fine in the past with the little breather filter on the valve cover. Until one day it just starting spraying out of the valve cover. I do have an extra new breather filter cause my old one is clogged right up, I could try running it but i'm pretty scared its just gonna blow out my valve cover again.

 

[dustyboner]

I never could find the compression test numbers i was looking for but around 180 psi sounds right.

I think you should have done the compression test when the engine was hotter. The FSM says to check it when the coolant temp is 178-203 F. Its a thermal expansion thing, If you let it cool down the pistons will contract.

So your running the catch can sealed, correct? as in without a breather filter.

Is your oil at the proper level? I just want to make sure its not overfilled. I have seen alot of people put in 5 qts when changing the oil instead of 4.5 qts. Over filling the oil can cause blow by problems.

If you ask me, the barb on the valve cover (for hose to CC) is too small. In the video you posted, the guy is running -10(AN) lines and fittings on the CC and VC ..
-10 is roughly 1/2" ID

Personally i would try swapping the hose connections on the valve cover. the smaller line to the PCV , the large one to CC. At least temporarily to see if it makes a difference.
something like this

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I also came across this which goes along with what i just said.

bgbmxer::
One thing I have found with setting up catch can setups is if your lines are not flowing enough air you get more oil then the clear/milky mixture. I run 5/8 hose on my setups pulling from both ends of the vc on my srt4 then a tube to the intake off the catch can.

On my td I run just one hose from the vc to the catch can then from there to the air box. Only time I had the dipstick eject or any oil in the airbox was due to it freezing past the baffle level so it had to go somewhere. Hate the freezing issues.

quote source

 

[Brad Bell]

Yes I have the catch can hooked up as a sealed unit. I think you are right though about the lines being too small, I'll try swapping the hoses like you said. However what about my pcv valve? It won't fit on the smaller fitting on the VC, should I just run the check valve instead? What's going into my catch can is just oil, could hook up a drain setup so it would drain back to turbo return line?

 

[dustyboner]

in that picture i used a pcv valve off a RSX but you could probably use a 4g63 one.

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It should be the right size for the hoses.

you don't want the catch can draining back to the crankcase. There will be water vapor and corrosive vapors along with the oil vapors that go into the catch can.

mishimoto has a good article on all this stuff
https://www.mishimoto.com/engineering/2016/01/blow-by-101-what-is-blow-by/

 

[1cleangsx]

Dude if your making enough power just go vented, period. I tried the check valve behind the pcv, no change, the best way to relieve crank case pressure from too much cylinder pressure is to VENT to atmosphere, assuming it’s not a faulty pcv, or blown rings, the best way is to ditch a pressurized sealed set up and let the pressure escape thru vents on the valve cover. I’m running 2 10an lines to a real street catch can with NO baffles and very little oil collecting. I was blowing out the dip stick on an fp red at 35psi, now pushing 34psi on a bolt on 35r,(dsm82). I can go wot 4th gear on the on ramp the dipstick doesn’t move, the sealed set up with vacuum from the vacuum was meant for 200hp, at some point the crankcase needs to breathe

 

[1cleangsx]

Sorry I meant sealed set up from the factory