Kinda weird Question regarding valve covers

[240 Trainee]

Ok, I have seen two types of valve covers, specificlly for the intake side. One type is smooth with a 90* elbow sticking up in the middle for the breater, the other kind has a hump towards the front (RWD engines) similar to the exhaust side that has the breather attached to it. Whats the differance in function between the 2? I happen to have 2 sets, one of each, and I was just curious.

[240 Trainee]

quick google image search - hump -

smooth -

Looks like a majority have the hump, I just don't get the reason for it.

[nismoplsr]

this is just a wild guess but...

I would think that the smooth is an earlier design. The humped ones have baffles in the humps that seperate oil from the air. The one without the hump most likely has no baffles thus more oil will make it out of the valve covers.

[Akihisa]

If you take the cover off, the hunmp has a plate screwed to the bottm. To me, it looks like it's there so the cams don't fling oil up to the breather hole. Only air

[float_6969]

The FWD CA's use the non-humped type. I'm not sure of the reasoning behind swapping it. Maybe the UKDM motors didn't have the hum either? I've never seen a RWD CA that had the smooth cam covers stock. AFAIK, all of the FWD CA's had the smooth ones.

I could be wrong...

[Rusted_PS13]

Is the valve cover two piece or one piece excluding the spark plug cover?

[TurboTuli]

its two pieces...

[flohtingPoint]

The FWD CA's use the non-humped type. I'm not sure of the reasoning behind swapping it. Maybe the UKDM motors didn't have the hum either? I've never seen a RWD CA that had the smooth cam covers stock. AFAIK, all of the FWD CA's had the smooth ones.

I could be wrong...

Not UK 200sx's Brother. Mine is German, but it has the same four port head as the rest of Europe and it has the hump.

[float_6969]

Cool, then it must be a FWD thing.

[NeedCAforS13]

Its a DET/DE thing from what I've read. Not rwd/fwd. I have a set of FWD covers and they acutally have an indentation down in the middle of the intake valve cover for the funky throttle body and crossover pipe deal that the pulsars run.

Sean

[float_6969]

OOHHH, that makes sense I guess. The DET's run baffles due to the increase blowby from the forced induction. They wouldn't be nessicary on the N/A variants.