Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Workshop Note - GDI Oil Breather

!00% agree with Griffo and it's not just for GDI engines.

The effect on "regular" engines is that the crankcase gasses enter the inlet manifold and "dilute" the nice clean inlet air thus slightly reducing the potential power output.

By venting the crankcase to air (either with a catch tank or without) you clean up the intake gasses and can more reliably tune the ECU for optimum running.

However, I'm not sure that doing this on later emission controlled cars will not affect the MOT.

Sure they don't do a full sealed chamber emission test and the standard emission test will not pick up the loss of the PCV system but they are supposed to check that the emission control systems are intact.

On later cars, would it show up a fault code of some description.

I thought I read somewhere that the ECU can detect faults in the emission control system. Could be wrong on that though.

Well I went under this morning and it's not great news. Access is pretty much impossible without dismantling some of the components, and it's hard to see the breather, even with the camera thrust into the cavity.

Not here.....


But here.....


I understand the ins and outs of crankcase pressure. My first Midget had a pancake valve over the inlet manifold, inside which was a rubber diaphragm. This was standard BL for a while. When the diaphragm got pin-holed, inlet vacuum had the ability to suck oil out of the sump and turn it into a smokescreen. That was my first taste of emission controls way back in 1971.

I don't particularly want to vent to atmosphere, so I will stick with what I have for now. Interestingly that tank isn't airtight. I tested it and there's an air bleed through the cap, which I suspect is by design. So it will have an effect on crankcase pressure in a minor way.

So I turned my attention to the air intake, because last time I ran out of Reflect-a-Cool before I could do the front section.

The front of this is 'unfinished'.



I fitted a neoprene edge.....very fiddly, and took three attempts! And added Reflect-a-Cool.

Does the GDI have a PCV fitted to an oil separator.

In which case there's no point plumbing to the catch tank and then to the manifold.

The oil separator will do the same job as the catch tank.

I know it's a different engine but that's the arrangement Ford used on the PCV system on the Zetec.

There's nothing recognisable as a PCV valve. The whole thing is sealed. The Cam cover vents directly into the main air feed pipe just ahead of the throttle body. The breather which Griffo identified is directly from the crankcase into the inlet manifold, with the spring loaded ball bearing anti backfire valve.

That appears to be it.

Griffo, could you put a link to the pictures of that in here? Or maybe some better gifted TM member could draw a schematic of where to find the second breather pipe...? We're so close to solving this "engineering masterpiece"!

My car had already done 27k miles when I purchased, so I figured that I needed to do Something sooner rather than later. Read lots of stuff about the GDI issue in general but didn't find anything specific for the Ford/Mazda engine, I also remember reading something about how a non-turbo GDI may be less affected.

I considered for some time, removing the Intake manifold as it would enable me to
a) find the bottom PCV connection with a view to fitting an Oil catch can and
b) to inspect the back of the intake valves and determine how bad they were fouling.

Did some research on how to remove the Intake manifold, but without a Haynes manual I didn't know things like torque settings for the bolts or if any gaskets would need replacing when putting it back together, so I decided it was a bit beyond me and didn't bother!.

In the end I just treated with CRC GDI Valve Cleaner and I'll repeat at regular intervals.

Hello Mark,

see at „GDI powered by FORD“ http://www.talkmorgan.com/ubbthreads.php/topics/726807/plus4-2-0-gdi-powered-by-ford#Post726807

The engine is fitted in the MAZDA MX 5 „nc“ (2.0 Liter, 160BHP). There also some VOLVO V40 around (2.0Liter, 152BHP).

For the MAZDA is a Heynes available.

Greets René

Did a little research on this and found a good video on intake valve cleaning that will guide you through the process - on a Ford Focus, though. Maybe I will give this a try on my 2018 +4 (EDIT: has run 15.000km so far) and produce a video as I fiddle around the engine bay, if there is demand from this fine community.

I for one would be very interested, especially as you will be able to visually inspect (Photo?) the back of the valves and see just how much this is a problem.

How many miles has your Plus 4 covered? mine had done 30k and wasn't displaying any of the symptoms associated with the problem.

WRT to a manual I trawled through the links provided by Rene and some other threads on TM, I think this US Haynes Manual for the Ford Focus will cover the Morgan Engine. https://haynes.com/en-gb/ford/focus/2012-2018-0 it's only available in print and since I decided not to take the intake Manifold off I haven't bought it.

Best of luck.

Gents, it is done: I have successfully removed the intake manifold - and to my despair, I can confirm that the Plus 4 GDI also tends to clog up the intake valves because of the PCV. See my short video of removing the intake manifold. I will now install an oil catch can to at least slow down this process significantly - more to follow!