Crankcase ventilation - let's talk upgrades

[Boxman]

So I've read here and there that the stock crankcase ventilations on our 5-pitters is pretty bad. That being said, would those of you who have made modifications like to give some views on what you did to yours and why?

Entry level upgrades, what's easy?
Next level upgrades, what's hard but worth it?

If you could chime in on what the bottlenecks of the system are, and more importantly what exactly the effects of those bottlenecks are on engine performance, I'd appreciate that a lot.

[DScottM]

Very interested to see what comes up here!

[bob82pigdog]

6 hours ago, DScottM said:

Very interested to see what comes up here!

Me too. 

[Ol' Dirty Noodle]

@lookforjoe

@VulvaS40T4

@dougy

@Tightmopedman9

help???

[hotpantslovebug]

Stock pcv - good for stock

Stock pcv with drilled out ptc

Stock box with 5/8 oil rated hose and copper 90 degree- good for higher mileage- more blowby 

Stock box -10AN line run to catch can back to pcv. Works well with no restriction. more maintenance, fills up fast in the winter and if it freezes you will pop the dipstick and spray oil. 

Stock box vented straight to the ground- works well for my 16t and EFR7064 @18-19lbs base tune, this option is slightly messier and sometimes smelly but basically allows no pressure build up and i have yet to see my oil level drop.

Next option is the above with an oil cap vent https://yoshifab.com/store/billet-volvo-vented-oil-cap.html

Also RNC block tapped near oil drain for addition breathing if needed.

Aaron has also vented to exhaust, his build thread has pics. This is common among drag racers where a check valve is installed in the exhaust to help pull and then semi burn in the exhaust.

This isn't the best in street turbo cars due to exhaust back pressure but to each their own.

It comes down to how much blowby your engine has. If you read hussiens entire build with his wagon he made numerous pcv modifications. It seems difficult  to developed a closed system in which no point becomes a restriction at some point. Also without a catch can you will be feeding oil mist into the intake which isn't very good for your fuel mixture or MAF. 

Also the newer RN breather box has a larger capacity but will not work with the stock N intake many use for RN swaps. 

Both matt and aaron have run -10AN fittings on the valve cover and have stated it does more bad then good because unless you have baffles welded in you still pump a lot of oil out the vents. 

 

[Ol' Dirty Noodle]

Great response, for my current state I'm probably just gonna pull the hose out of the intake, pop a filter on it and vent atmospherically and block up the bung on the intake.

[Stefan Mohammed]

I ran a 3/4" hose out of the stock PCV box into a catchcan. The out of the catch can fed into a exhaust scavenger and the can drained back to the stock PCV box with a 3/8" drain. Worked well for close to 30 PSI of boost. 

[TryingBe]

I found with the older engines, even with new PCV parts, it is not enough. The stock PCV pipe from the separator to the intake is severely undersized for an older engine. Also, the hole at the heating element at the PTC valve is tiny, like smaller than 1/4 inch tiny. Both will restrict the flow of the crankcase gases.

To address those issues, here is what I do. Get the below parts.

A 3ft 5/8 oil compatible hose. Do not use silicone hose, as it will "sweat" oil. Do not use heatercore hose, it is not rated for oil, it will become soft and you'll have to replace it sooner. This is what I use. Buy 3, as it is sold by the foot.
http://www.ebay.com/itm/291442927889?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

One 3/4 elbows from your local hardware store. (5/8 will be the wrong size!)

A 3 feet 3/16 inch or 1/4 inch vacuum hose to replace the small hose from the intake manifold to the PTC valve. I prefer silicone hose for this.

Optional, get 6 of this. I like their clamps.
https://www.ipdusa.com/products/4768/105027-hose-clamp-15-24mm-12mm-width

Optional, wireloom to protect the hose.

Take a unibit and drill out the PTC valve holes to as big as you feel comfortable. I think I drilled mine out to about 1/2 inch.

Remove the intake manifold and replace that stock PCV hose, I cut a short hose and then use a 90 degree elbow, than a long hose to the PTC valve. Replace the vacuum hose to the intake manifold to the PTC valve with the new one. Then reinstall the intake manifold.

All the crankcase gas have to go thru that tiny PTC hole!!!

Installed on car

[VulvaS40T4]

Main thing is that if you use normal gasoline blow by wont be big problem but switching to E85 ethanol fuel increases blowby.

So stock breather is okay for about 500hp-600hp with hose nipple about 1" to outside air with both e85 and gasoline. After that you need dual catch can and it will work to 1000hp. :)

Also always return oil over the oil level, stock breather box returns oil under oil level which is okay under 500hp but not after that.

[bob850]

This may be a dumb question, but will drilling out the hole in the PTC heater element make it harder to build boost?  I'm having trouble visualizing how that pressure loop in the line between the manifold and PTC affects the overall system.

 

I was planning to drill out the PTC as a first step to see if that helps with crankcase pressure, but haven't got around to it yet.

[boxpin]

Everyone is going to have their own opinion on this. I started by opening up my stock box and adding a 1” line out of it. That went to a ProVent which eventually went to two ProVents in series. From there I tried to vent to atmosphere then back to the stock PTC. I started thinking about this and realized I had done NOTHING to help with the block venting since the PTC hole is still stock so no matter what you do without changing that exit point it wont make a difference how large you make your system.

Another word of advice, I started developing white milky oil on my dip stick and oil cap. Thought I may have a blown head gasket. Inside the block on all engines there is moisture vapor, condensation…that has to be able to escape and cannot do it by itself. It will remain in the block no matter what venting system you put in place, it needs to be drawn out. The vacuum on the crank case system does this. When you vent to atmosphere from your stock box there is no vacuum draw on the block and you will build up moisture inside your engine. Whatever design you end up with, you need a vacuum pull.

The stock system works great until you start increasing your HP. After that you need a way to let that extra pressure out of the block. Gases and vapor will be drawn out when you are driving normal but when you are on boost that pressure needs to be released immediately.

Recommendation: Leave the stock system alone and add another vent. This keeps the daily driver w/vacuumed system venting your block. Add another vent somewhere to allow higher block pressure to escape when needed.

[Volvo5.0]

I'm not sure drilling out the tiny hole in the PTC is the answer. The engine vacuum is only present when at idle or when cruising. Under hard acceleration when the engine is in boost, there is actually boost pressure in that vacuum line. Making the hole in the PTC nipple bigger will let more boost pressure in and in turn pressurize the system. Putting a one-way vale in the vac. line from the intake to the PTC is helpful. Volvo actually figured that out and started using a one-way valve on the vac. line sometime around 2004-2005.

When in boost the increased airflow across the hole in the bottom of the PTC actually creates a suction to help pull vapors out of the crankcase.

[Ruhl98t5wag]

What does the one way valve look like for a vac line? Thanks

[Volvo5.0]

55 minutes ago, Ruhl98t5wag said:

What does the one way valve look like for a vac line? Thanks

After I removed the air pump system (SAS) I used the one-way valve that was originally used on the vacuum line from the intake manifold to the SAS solenoid PN#9135666. I installed 2 separate vacuum lines on my PCV.

One from the PTC to the vacuum tree...

And one from the top of the PCV box to the vacuum fitting on the end of the intake manifold, similar to the setup on the P2 cars...

[Boxman]

Loving the suggestions and discussions so far! @Volvo5.0 what's your reason for putting a second vacuum line closer to the box? Just more idle venting capacity? Have you done anything to relieve the additional crankcase pressure under boost?

Really like the idea of one-way valves on the vacuum lines. Though I think when talking about drilling, people meant the larger hole on the bottom of the PVC as that's the one venting the crankcase under WOT. I think the drilling of the hole would certainly have a benefit, and also think the vacuum draw of your boosting turbo at the intake will be stronger than the vacuum the Venturi effect provides at the orifice (and with a larger orifice the Venturi effect should still be there btw). Just a gut feeling as I haven't run the numbers though, I could do that in some spare time next days if people are interested.

Does anyone have any idea why Volvo put such a small orifice there in the first place? Does it have something to do with that heating element that's there, intentionally holding up the exiting crankcase gases or something?