PCV

[M1ck3y]

As we know the l87 pcv is slightly different the the l86. It looks like the valve from the valley is capped and they just run a hose from the valve cover to the manifold. This is something I'd like to do to my l86 but I dont know if there's any ramifications. Does anyone know if GM made changes to the engine in order to support this on the l87? 

 

 

Edited July 26, 2021 by M1ck3y

[M1ck3y]

I know, crankcase ventilation has been covered a lot! But there's nothing about converting to the l87 setup. It's either various routing option's with catch cans, venting to the atmosphere, venting into the exhaust and so on...

 

If I put a plug on the pcv valve and put a vacuum on just the drivers side valve cover is it safe? Will it achieve the the pcv systems intended purpose.

 

The sole reason I'm considering this is because the valve cover is baffled and will result in less oil reaching the manifold. But I have no clue if the valley is somehow different which allowed gm to do this with the l87.

[newdude]

The L87 doesn't have a valley plate to port off of which is why its different.

 

L87 went to the DFM so no more VLOM.  It has an LS non AFM style plate in the valley.  Where the L86 would have pulled foul air from that plate is now the wiring harness into the valley for the DFM solenoids underneath, hence why the foul air goes from the left rocker cover to the intake now. 

 

The L86 has a replaceable PCV valve in that VLOM plate that the hose attaches to.  

Edited July 26, 2021 by newdude

[pokismoki]

why would you guys want to do this?

[M1ck3y]

38 minutes ago, newdude said:

The L87 doesn't have a valley plate to port off of which is why its different.

 

L87 went to the DFM so no more VLOM.  It has an LS non AFM style plate in the valley.  Where the L86 would have pulled foul air from that plate is now the wiring harness into the valley for the DFM solenoids underneath, hence why the foul air goes from the left rocker cover to the intake now. 

 

The L86 has a replaceable PCV valve in that VLOM plate that the hose attaches to.  

 

So if I'm understanding this correctly... The valley in the l87 no longer builds pressure/foul air, its basically sealed from the rest of the engine because it now uses solenoids. Correct?

[newdude]

1 minute ago, M1ck3y said:

 

So if I'm understanding this correctly... The valley in the l87 no longer builds pressure/foul air, its basically sealed from the rest of the engine because it now uses solenoids. Correct?

 

 

I guess LOL.  I'll have to find a way to post pictures of it all here somehow.  Gimme a bit and I'll see what I can do.  

[M1ck3y]

18 minutes ago, pokismoki said:

why would you guys want to do this?

 

I was hoping to pull a vacuum on just the drivers side valve cover so it would separate the air from the oil. Less oil would make its way into the intake manifold, resulting in less carbon buildup on the valves. 

[M1ck3y]

So I'm seeing the differences more clearly now. But I'm failing to understand why you would put a pcv valve there... Is it purely because of afm? If all 8 lifters are locked would it not remove the need to vent there?