LLY: CCV Scavenging VS Vented to Atmosphere

[Bdsankey]

For those duramax owners running CCV scavenging fittings into the exhaust, are two sufficient? This is on an LLY with stock valve covers. Will I need to add an extra port on each valve cover to ensure it doesn’t build crank case pressure?




I’m planning on adding a vibrant 4 port catch can with a single -10 line off of my Merchant auto reroute fittings. I know Vibrant doesn’t make the e-vac fittings any longer but I found some that seem identical on amazon. I’m trying to find the actual vibrant version as I know they work damn well.

 

[Chevy1925]

its going to be all dependent on how much blow by you have on whether or not you need more scavenging or not. put a low pressure psi/vac gauge on a valve cover or line and see what its doing. if you are going into vac or holding 0 psi, you are good. having a little vac is best.

 

[Bdsankey]

its going to be all dependent on how much blow by you have on whether or not you need more scavenging or not. put a low pressure psi/vac gauge on a valve cover or line and see what its doing. if you are going into vac or holding 0 psi, you are good. having a little vac is best.

As of now all I have is 5/8" hoses ran directly from the valve cover to the atmosphere. Each side/bank goes to just behind the rear mount on the upper control arm outside the frame. I don't have a ton of blow by when warm BUT I do imagine a drag strip will not be happy with me if I show up that way to run consistently. I am doing this as just a way to make the truck cleaner for repeated competition use.

 

[ZeroGravity58]

I never really looked into it but what about running a vacuum pump?

 

[Bdsankey]

I'm mainly looking for a way to not put oil on anything after a hard run. My truck doesn't make any puddles after driving hard BUT I want to do it right to help keep things going smoothly.



I do plan on putting check valves between the evac fittings and the catch can just incase there is a nitrous backfire or something similar to help ensure there are not any major side effects/downfalls incase it happens due to sudden pressure spike.

 

[Chevy1925]

I'm mainly looking for a way to not put oil on anything after a hard run. My truck doesn't make any puddles after driving hard BUT I want to do it right to help keep things going smoothly.



I do plan on putting check valves between the evac fittings and the catch can just incase there is a nitrous backfire or something similar to help ensure there are not any major side effects/downfalls incase it happens due to sudden pressure spike.

that wont do anything other than blow the hoses off. leave them open. if you loose a piston or backfire or something that will put a massive pressure spike into the hoses, i would make DAMN sure they stay connected and free flowing to the exhaust. you dont want that oil hitting your tires at 100+ mph. been there done that when we lost a piston in the stock engine of the cummins running down the track. you porbably wont stop all the oil from hitting tires but the more you can re-direct, the better.

 

[Bdsankey]

that wont do anything other than blow the hoses off. leave them open. if you loose a piston or backfire or something that will put a massive pressure spike into the hoses, i would make DAMN sure they stay connected and free flowing to the exhaust. you dont want that oil hitting your tires at 100+ mph. been there done that when we lost a piston in the stock engine of the cummins running down the track. you porbably wont stop all the oil from hitting tires but the more you can re-direct, the better.

10-4. Besides that correction, do you see a problem with anything else? Are the factory fitting locations sufficient? I'm planning on draining the can before every hard use or once a week if I drive it daily until I determine exactly how often it needs it. I don't want to run it back to the oil pan as I am worried that some moisture may accumulate in the catch can so I intend on just draining into a bottle/waste oil container.

 

[Chevy1925]

na rest looks good. the next big deal is making sure you weld in the venturies right

 

[Bdsankey]

na rest looks good. the next big deal is making sure you weld in the venturies right

Fingers crossed hahaha. Those to me are pretty straight forward.

 

[gmc502]

For those duramax owners running CCV scavenging fittings into the exhaust, are two sufficient? This is on an LLY with stock valve covers. Will I need to add an extra port on each valve cover to ensure it doesn’t build crank case pressure?




I’m planning on adding a vibrant 4 port catch can with a single -10 line off of my Merchant auto reroute fittings. I know Vibrant doesn’t make the e-vac fittings any longer but I found some that seem identical on amazon. I’m trying to find the actual vibrant version as I know they work damn well.

maybe reach out to these guys,,doesn't say they're out of stock.may get lucky

https://www.skspeed.com/vibrant-118...avenger-kit-with-stainless-steel-angled-bung/

 

[Tothemax]

https://www.amazon.com/PQYRACING-Un...s+Steel+E-VAC&qid=1565119435&s=gateway&sr=8-3

 

[Bdsankey]

https://www.amazon.com/PQYRACING-Un...s+Steel+E-VAC&qid=1565119435&s=gateway&sr=8-3

Correct, this is the amazon knockoff I am referring to. My question isn't so much "what fitting" or "who has it" but more so will this concept work AND do I need to mod the valve covers for it to work efficiently. If I go this route it will only be the Vibrant fittings as I know they are proven to work well in this type of application. I'm just looking for a clean way to expel crank case gasses post catch-can that isn't using a filter. I feel more comfortable plumbing the lines to evac fittings than I do running filters on top of the catch can.




James answered these questions. While I disagree about check-valves, he has more experience in this instance than I do without a doubt. I know I've talked to a few other guys using the concept on other platforms with mixed instances of people using check valves. It seems about 50/50 on those using them vs not. The guys using them were more worried about keeping a major pressure spike out of the crankcase at all costs whereas some were more concerned with oil getting under the truck.

 

[rfletes79]

I ran the scavenge setup on the Chevelle. It pulled too much oil out and made a mess in my exhaust. I’ve since switched to a catch can mounted to my radiator support with 2 breathers and baffles in the tank with an oil return line back to the pan. Seems to work much better just need to clean the breathers every so often.

 

[Bdsankey]

I ran the scavenge setup on the Chevelle. It pulled too much oil out and made a mess in my exhaust. I’ve since switched to a catch can mounted to my radiator support with 2 breathers and baffles in the tank with an oil return line back to the pan. Seems to work much better just need to clean the breathers every so often.

I'm looking at using the Vibrant 4 port catch can with 2 lines coming from the engine (one on each bank) and 2 lines going to the evac fittings. Do you think it'll pull to much out then? I don't plan on draining back to the pan, although I've thought about it.

 

[Tothemax]

Correct, this is the amazon knockoff I am referring to. My question isn't so much "what fitting" or "who has it" but more so will this concept work AND do I need to mod the valve covers for it to work efficiently. If I go this route it will only be the Vibrant fittings as I know they are proven to work well in this type of application. I'm just looking for a clean way to expel crank case gasses post catch-can that isn't using a filter. I feel more comfortable plumbing the lines to evac fittings than I do running filters on top of the catch can.




James answered these questions. While I disagree about check-valves, he has more experience in this instance than I do without a doubt. I know I've talked to a few other guys using the concept on other platforms with mixed instances of people using check valves. It seems about 50/50 on those using them vs not. The guys using them were more worried about keeping a major pressure spike out of the crankcase at all costs whereas some were more concerned with oil getting under the truck.

i have 2 of the vibrant fitting about 6 inches past my down pipe. i have stock valve covers with the diaphragm taken out. been this way for a while now everything has worked well

 

[Tothemax]

p.s. pretty sure the vibrant fittings are no longer available

 

[Bdsankey]

i have 2 of the vibrant fitting about 6 inches past my down pipe. i have stock valve covers with the diaphragm taken out. been this way for a while now everything has worked well

Good to know, so it should all work well with a catch can to help "lessen" the amount of oil reaching the exhaust.

 

[DAVe3283]

Interested in how this works out. I have a LB7 (built in catch can and oil drainback to pan), and it just vents to the bottom front of the motor. On my stock motors, this works perfect, but on my built motor, it has enough blowby that I can smell the PCV vapors at idle through the A/C (or walking near the front). It eventually builds up some oil and will drip a drop or 2 on my driveway if I don't wash the front of the motor down every 6-9 months. Mildly annoying.

I've long considered one of those venturi adapters into the exhaust just to get the fumes back behind the truck without the risk of freezing the hoses up if I were to simply run 15' of line down the frame or something. So I am curious to hear how this setup works out for you.

 

[Bdsankey]

p.s. pretty sure the vibrant fittings are no longer available

Correct, I said that in my first post. Some vendors still have stock and there are plenty of knockoffs on ebay and amazon.

 

[Chevy1925]

Interested in how this works out. I have a LB7 (built in catch can and oil drainback to pan), and it just vents to the bottom front of the motor. On my stock motors, this works perfect, but on my built motor, it has enough blowby that I can smell the PCV vapors at idle through the A/C (or walking near the front). It eventually builds up some oil and will drip a drop or 2 on my driveway if I don't wash the front of the motor down every 6-9 months. Mildly annoying.

I've long considered one of those venturi adapters into the exhaust just to get the fumes back behind the truck without the risk of freezing the hoses up if I were to simply run 15' of line down the frame or something. So I am curious to hear how this setup works out for you.

you ever pull the front inspection plate off the factory catch can? wonder how much junk builds up in there and stops them from working