3.6 conversion hose & catch can Q's

[BarryJB]

My '85 3.6 conversion ('95 OBD-I 993 mill) is now CA legal - just got the doorjamb sticker earlier this month, 1st try, so very happy…

There are still a couple of hose details which could be closer to the smog and visual configuration used on a 993. While these were no issue with this inspection, it might be different down the road.

1. Carbon canister. Evap. system all hooked up, but I believe (still trying to trace it back there) canister purge line is routed into the air intake somewhere behind the engine, which works fine of course. The '95 993 3.6 still has the canister purge solenoid (top left of engine on the "disconnects" metal bracket) plumbed in - I know most smog-free guys don't use this, but is there any reason why I SHOULDN'T use it? It's just an extra bit of hose and the engine's getting dropped this week for other stuff. Right now the port on it is conspicuously capped off (blower deleted). Might not pass muster next time…

2. Oil tank - the 3rd small breather line. I borrowed this pic of warpspd Ryan's from an old thread here. Presently the 3rd small breather line from the oil tank is still connected to the 3.2's Auxiliary (or Ambient/Extra) Air Control Valve (ACV) on the engine bay wall next to the oil filler neck, and the other side of the ACV runs to the port shown in the picture. Since there's no thermoswitch on the throttle body on the 3.6 - it uses the Auxiliary Air Pump system instead - there is no control line from it to the ACV control port (on top on mine), which is presently uncapped.

This means that there is another conspicuously missing line, and that since the ACV never opens, essentially this oil tank breather line and the nipple on the inlet manifold are both blocked off.

Clearly the 3.2 ACV has no place in here at all any more.

On the 993 oil circuit, it also shows a 3rd small breather line from the oil tank which goes to the inlet manifold - is the nipple shown in the picture the correct location for that hose? Assuming it is:

Regardless of the original auxiliary air feed use, is the 3rd small breather line on the 3.2 oil tank functionally equivalent to that on the 993 oil tank, so it can be hooked up to the engine exactly the same way as the 993 oil tank's 3rd small breather line?

So if the ACV removed - if the above assumptions are true - its position could just be bypassed with an open connection?

Or…

The 3.2 and 993's 3rd breather nipples are not functionally equivalent - so use a blocking piece between them? That would retain the correct appearance and hose routing for the 993 engine, and cap off both oil tank and manifold nipple, which is what I believe the smog-free guys do anyway?

3. Catch cans. This will be a dual use car. A bunch of catch can threads here… but has anyone tried either the ProVent 200 (or one of their smaller units) or the BMS BMW oil separator catch can in the oil filler neck breather line? ProVent 200 has 1-in fittings, BMS ≈19mm (3/4-in).

Thanks for any help with anything here!