PCV/Catch Can routing for LS3/L92 C5
05-11-2018, 09:07 PM
#1
PCV/Catch Can routing for LS3/L92 C5 I'm almost ready to fire up my C5 for the first time after swapping in an L92. Just need to figure out the PCV system. The car will see a fair amount of time on local road courses so I want to install a catch can as well to prevent oil from entering the intake manifold, which was an issue when I ran the car with the old LS1.
The car has an L92 from an '08 Escalade. The valley towers (normally used for VVT) have been plugging with NPT plugs and the engine uses the typical L92 valley cover with the 8 o-rings underneath it as extra security. The valley cover does NOT have the PCV nipple like the LS6 valley cover has.
How should I route my catch can and PCV system?
Do I need a separate external PCV valve?
I want to eliminate any and all oil consumption, especially on track.
This is the rough draft I came up with.
The car has an L92 from an '08 Escalade. The valley towers (normally used for VVT) have been plugging with NPT plugs and the engine uses the typical L92 valley cover with the 8 o-rings underneath it as extra security. The valley cover does NOT have the PCV nipple like the LS6 valley cover has.
How should I route my catch can and PCV system?
Do I need a separate external PCV valve?
I want to eliminate any and all oil consumption, especially on track.
This is the rough draft I came up with.
05-13-2018, 01:03 PM
#3
11 Second Club
iTrader: (3)
That should work just fine the way it's shown in diagram.
05-13-2018, 03:09 PM
#4
TECH Senior Member
Yep. VERY simple, VERY effective!
05-14-2018, 03:52 PM
#5
11 Second Club
iTrader: (3)
05-14-2018, 08:29 PM
#6
TECH Senior Member
05-15-2018, 02:35 AM
#7
Mine's a crate LS3, hoses from both valve covers and the valley cover were routed into a ventilated catch can. The car does half serious circuit work only, bugger all ended up in the can. I would like to ventilate the sump too, these engines need all the ventilation they can get.
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05-15-2018, 09:31 AM
#8
11 Second Club
iTrader: (3)
Mine's a crate LS3, hoses from both valve covers and the valley cover were routed into a ventilated catch can. The car does half serious circuit work only, bugger all ended up in the can. I would like to ventilate the sump too, these engines need all the ventilation they can get.
05-15-2018, 10:39 AM
#9
For what it's worth I only ever had an oil consumption issue with the old LS1 when I ran it hard to redline, then let off the gas and let the engine coast down from 6000 to 3000 rpm. The vacuum of the manifold pulled in oil from the valve covers and pooled in there, then when the throttle opened back up it sucked the oil into the heads and burned it off. It wouldn't do it under any other condition. Granted I had no catch can on there, so it was a straight shot from the VC to the IM
07-08-2018, 12:34 PM
#10
Update - I just did a track day with the setup shown in the original post and still had oil consumption issues, though not as bad as it used to be. There was a significant amount of oil being sucked from the driver's rear valve cover to the air duct:
The next step is to add another catch can in that line, unless there's a way to prevent the oil from getting sucked through.
The next step is to add another catch can in that line, unless there's a way to prevent the oil from getting sucked through.
07-09-2018, 02:36 PM
#11
11 Second Club
iTrader: (3)
Update - I just did a track day with the setup shown in the original post and still had oil consumption issues, though not as bad as it used to be. There was a significant amount of oil being sucked from the driver's rear valve cover to the air duct:
The next step is to add another catch can in that line, unless there's a way to prevent the oil from getting sucked through.
The next step is to add another catch can in that line, unless there's a way to prevent the oil from getting sucked through.
This will keep it from happening!
07-10-2018, 01:47 PM
#13
11 Second Club
iTrader: (3)
I suppose you could run a vacuum pump but I don't think it's necessary for a street/strip build. They're mostly for racing applications where low tension rings are used and it can produce a power increase.
07-18-2018, 05:22 AM
#14
For what it's worth I only ever had an oil consumption issue with the old LS1 when I ran it hard to redline, then let off the gas and let the engine coast down from 6000 to 3000 rpm. The vacuum of the manifold pulled in oil from the valve covers and pooled in there, then when the throttle opened back up it sucked the oil into the heads and burned it off. It wouldn't do it under any other condition. Granted I had no catch can on there, so it was a straight shot from the VC to the IM
07-20-2018, 08:42 AM
#15
BINGO! this is why the oil ends up in the manifold, you know those studs who like to drive around in a gear that keeps the rev's really high and then pulls there foot off of it because it sounds sooooo cool, those are the only people that need catch cans, swapped my stock LS2 mani for a radically ported one and you couldn't get TP wet with the residue in the manifold at 75000 miles on the stock one.
07-20-2018, 09:59 AM
#16
[QUOTE=LQ4-E39;19934129]Or those studs that do that at the end of a long straight on the road course braking for a turn?
they ARE braking for a turn AND there downshifting using engine compression too slow them down there not just running it up to 6000 in thgird and pulling their foot off because it sounds cool, u missed the vacuum pump too which keeps the atmospheric pressure equal in the engine block{crankcase} otherwise they might suck all the oil out, I do track days, why isn't my mani full of oil?
they ARE braking for a turn AND there downshifting using engine compression too slow them down there not just running it up to 6000 in thgird and pulling their foot off because it sounds cool, u missed the vacuum pump too which keeps the atmospheric pressure equal in the engine block{crankcase} otherwise they might suck all the oil out, I do track days, why isn't my mani full of oil?
07-20-2018, 12:59 PM
#17
11 Second Club
iTrader: (3)
I've seen many NA and turbo builds and most of them ventilate the crankcase with breather cans not sealed catch cans. I've seen the affects of PCV on the intake manifold and engine components. I certainly don't want that happening to my parts over the course of time so I will do what is necessary to keep it form happening.
08-06-2018, 01:23 PM
#18
Ok, an update, with another setback.
I installed this:
Behind the driver's fender, on the frame, and ran a 3/8" hose from each valve cover directly to the ports on that air/oil separator to allow the crankcase to breathe. The valve covers are still stock from a 2008 Escalade at this point.
Nipples on the C5 air duct and LS3 intake manifold were capped off to eliminate any change of oil being ingested into the intake during high vacuum situation (high revs, decel, throttle shut).
I ran the car up to 6500rpm in 3rd gear and let off, and am still getting clouds of smoke out the back as oil is consumed. Since the intake tracts are capped there isn't any way for oil to get sucked in, so I'm somewhat stumped on how oil is entering the combustion chamber.
Valve seals are brand new, bottom end (original rings, etc) has about 80,000 miles on it. Thoughts?
I installed this:
Behind the driver's fender, on the frame, and ran a 3/8" hose from each valve cover directly to the ports on that air/oil separator to allow the crankcase to breathe. The valve covers are still stock from a 2008 Escalade at this point.
Nipples on the C5 air duct and LS3 intake manifold were capped off to eliminate any change of oil being ingested into the intake during high vacuum situation (high revs, decel, throttle shut).
I ran the car up to 6500rpm in 3rd gear and let off, and am still getting clouds of smoke out the back as oil is consumed. Since the intake tracts are capped there isn't any way for oil to get sucked in, so I'm somewhat stumped on how oil is entering the combustion chamber.
Valve seals are brand new, bottom end (original rings, etc) has about 80,000 miles on it. Thoughts?
08-06-2018, 07:31 PM
#19
11 Second Club
iTrader: (3)
Ok, an update, with another setback.
I installed this:
Behind the driver's fender, on the frame, and ran a 3/8" hose from each valve cover directly to the ports on that air/oil separator to allow the crankcase to breathe. The valve covers are still stock from a 2008 Escalade at this point.
Nipples on the C5 air duct and LS3 intake manifold were capped off to eliminate any change of oil being ingested into the intake during high vacuum situation (high revs, decel, throttle shut).
I ran the car up to 6500rpm in 3rd gear and let off, and am still getting clouds of smoke out the back as oil is consumed. Since the intake tracts are capped there isn't any way for oil to get sucked in, so I'm somewhat stumped on how oil is entering the combustion chamber.
Valve seals are brand new, bottom end (original rings, etc) has about 80,000 miles on it. Thoughts?
I installed this:
Behind the driver's fender, on the frame, and ran a 3/8" hose from each valve cover directly to the ports on that air/oil separator to allow the crankcase to breathe. The valve covers are still stock from a 2008 Escalade at this point.
Nipples on the C5 air duct and LS3 intake manifold were capped off to eliminate any change of oil being ingested into the intake during high vacuum situation (high revs, decel, throttle shut).
I ran the car up to 6500rpm in 3rd gear and let off, and am still getting clouds of smoke out the back as oil is consumed. Since the intake tracts are capped there isn't any way for oil to get sucked in, so I'm somewhat stumped on how oil is entering the combustion chamber.
Valve seals are brand new, bottom end (original rings, etc) has about 80,000 miles on it. Thoughts?
Okay you either have a lot of oil still in the headers and combustion chambers that have not burned off yet or you have a problem with your rings. I know this because unfortunately I've dealt with this issue before and had to tear the motor back down run a flex hone through the cylinders and re-ring all the pistons. Also if this is the case then you should be seeing oil fouled spark plugs so have you checked for that?
08-07-2018, 12:27 PM
#20
I use to have the catch can setup but still to much oil got in the intake carboning up the intake valves and pistons, not to mention the oil mixing with the air fuel mixture. Now I run one of these vacuum pumps.
What a different on how clean the valves and pistons stay and it runs so much better with a clean air/fuel mixture. It makes more power too!
Thanks
Christian
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