While I have the top of the engine in bits - I was idly wondering if anyone has reconfigured or fitted a proper, what you might call 'modern' style of PCV system to a V12.

By that, I mean an outlet in a cam cover or on the central block cover plate around the distributor, going to a pcv valve, going directly to the inlet manifolds.

The standard system appears to do pretty much nothing - the vent at the front of the Left bank attaches directly to the left side airbox, alongside which the PCV attaches to this joint, then goes into either inlet manifold via that small pipe which links the centre of each inlet manifold.

There might be a partial vacuum pull dependent on how restrictive your air filter/air intake pipe is I guess, but nothing like in a modern engine.

I would have thought a PCV valve from a similar/larger capacity V8 would probably have suitable flow characteristics.

I'm sure this has been discussed before but I couldn't find much in the search.

Pulling a vacuum in the crankcase would obviously have benefits in reducing oil leaks.

 

Andrew
I have done this mod, and it works really well. I used a nice catch can with a dipstick so yo can tell if it is filling up (so far in a year, about 2mm of oil in the bottom, if that):

I connected it directly to the "pig's snout" on the end of the B bank cam cover, located the canister in front of the rad stack, and ran the suction side from the canister outlet into the A bank manifold. Much better than the OEM version, and just blocked off the inlet into the B bank air box.

 

Hi Greg,
Interesting, thanks for the pics.
Are you not using any sort of PCV valve in your system then? Presume you're not having issues with pulling too much vacuum - smoke from exhaust etc?

Also, have you done any other modification to allow the fresh air 'into' the block that you are then extracting via your catch can?
Looking at the technical manuals for my other cars PCV systems which are reliable (Toyota, Subaru), this is how most of them appear to be designed.

 

Andrew
No valves, no fresh air inlets, no leaks from the sump bolts, and another pipe across the V gone! No ill effects at all. Remember that above about 1500 rpm there is not much vac in the manifold anyway.

 

TECHNICALLY the pipe on top of the engine is just the activation pipe. There is no oil vapour in there. The B bank side always has the crank case fumes. So it is vacume operated and only ever works at higher RPM (IIRC). The valve leading into The B bank air cleaner box is spring loaded and also a one way valve...