Pcv / venting a L76
Pcv / venting a L76 Like the title says , issues with pcv/venting issues , here's the history and situation . L76 / 6l80E out of a 08 G8 , complete DOD delete (valley pan w/u-shaped hose to TB , lifters , pushrods , Texas Speed 224 Cam , Pac springs , shut off in ECM ect...) GM performance Parts 25534398 aluminum valve cover w/modified oil cap in breather hole and matching D/S valve cover w/no holes , relocated coils , headers and a free flowing intake tract , all in a 69 Camaro .
The issue is that everything was fine while driving normally , but after several (10-15) 0 to 80-100mph WOT launches , the oil cap has gone AWOL ! I suspect a crankcase pressure issue account the solid , non-vented valve covers and the revised PCV system (new valley cover w/baffled line routed to TB . I don't recall what the original PCV system was on the L76 in the G8 was , but I suspect that there was some sort of vent/check valve located on the D/S valve cover . There is so much info on these issues out there that it has me kind of baffled as to a fix . I would really like to keep it a closed system of sorts , really don't want to do any type of catch-can/filter type setup . What am I missing here ? Suggestions ? I'm going to try and add a few pics to illustrate where I'm coming from .
The issue is that everything was fine while driving normally , but after several (10-15) 0 to 80-100mph WOT launches , the oil cap has gone AWOL ! I suspect a crankcase pressure issue account the solid , non-vented valve covers and the revised PCV system (new valley cover w/baffled line routed to TB . I don't recall what the original PCV system was on the L76 in the G8 was , but I suspect that there was some sort of vent/check valve located on the D/S valve cover . There is so much info on these issues out there that it has me kind of baffled as to a fix . I would really like to keep it a closed system of sorts , really don't want to do any type of catch-can/filter type setup . What am I missing here ? Suggestions ? I'm going to try and add a few pics to illustrate where I'm coming from .
On the g8 l76 the driver valve cover did have a vent in the back that was routed to the side of the intake with a molded plastic tube and the pass valve cover tube went to the side of the intake tube.
The gm covers dont have baffles. What you would want to do is get the 1le pcv oil cap and run it to the side of the intake tract. Gm has a kit, its somewhat pricey, but its all figured out for the most part.
Dont just run a breather as youll blow oil everywhere. The driver cover could be tapped and ran in line with the valley cover tube or the pass valve cover tube. That is an option also BUT you would need an inline baffle, metered orifice, or something like what the og g8 valve cover had to keep the oil mist and airflow to a min.
The gm covers dont have baffles. What you would want to do is get the 1le pcv oil cap and run it to the side of the intake tract. Gm has a kit, its somewhat pricey, but its all figured out for the most part.
Dont just run a breather as youll blow oil everywhere. The driver cover could be tapped and ran in line with the valley cover tube or the pass valve cover tube. That is an option also BUT you would need an inline baffle, metered orifice, or something like what the og g8 valve cover had to keep the oil mist and airflow to a min.
Last edited by tech@WS6store; Jun 16, 2017 at 12:14 PM.
This is a pic from earlier in the build that shows the u-shaped hose going from the valley cover to the intake . This would be considered the "dirty side"of the system , effectively drawing the crankcase vapors out from the valley area through the baffled system , correct ? ........The original L76 system would have been vapors drawn in where ? The front P/S valve cover tube or the rear D/S valve cover tube with the orifice ?
