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

Further to the alarming state of the GDI inlet valves shown earlier in this thread, the state of play with my own GDI had to be investigated. Now on 20k miles with 10k under my ownership. A recent rolling road test showed the engine to deliver roughly standard bhp with the graph showing evenly progressiive torque and bhp delivery. There has never been any trace of a hair trigger throttle.

The offside crankcase breather was diverted away from the inlet some time ago and the nearside crankcase breather was diverted more recently.

The video early in this thread proved invaluable. However, removing the inlet manifold proved challenging. There are 6 bolts fixing the manifold to the block, 5 at the top and 1 bolt in an extremely difficult location at the bottom. A 3/8"square drive rachet, extension and socket is essential, as is a magnet on a stick to withdraw and reloate the bolts.

url=https://tm-img.com/image/SfWkv][/url]
The stainless steel angled bracket to the water pipe interferred with withdrawal of the manifold, which in the fore-aft direction was effectively locked in. Not wanting to disturb the coollant pipes and hoses, the manifold was eventually withdrawn by levering the pipes clear. The offending bracket was duly cut off and replaced with an aluminium detachable bracket. There are 2 separate plastic christmas tree type fixings that tie a wiring loom to the manifold beneath the intakes and 1 on the outside. These were detached prior to manifold removal. It was not necessary to detach any electrical connections other than the one to the throttle body.


The blue plastic angle bend holds the crankcase breather. The original short pipe was replaced with a single longer pipe which now feeds to a catch tank.



The short breather pipe originally fed into the 15mm ID hole at the base of the manifold. This has now been plugged up. In the foreground is the single fixing bolt location at the base of the manifold casting.


Valves as found. On inspection, all valves were in far better condition than expected. Seafoam was sprayed onto the valves and left for an hour or so before cleaning.


The inlet tract length is just over 100mm. A small softish brush with short rod was inserted in a longer tube for cleaning via the drill before removal with a rag poked down with a wooden stick. At the end of proceedings the brush detached itself from its rod and had to be rescued via a piece of bent wire.


The replacement aluminium bracket made replacement of the manifold a breeze.

Now both crankcase breather pipes have been diverted away from the inlet manifold, there should be no further carbon build up on the inlert valves.

However, from these findings it would appear the valves had very many more miles in them before becomming coked up. Under my ownership the valves were treated to the recommended Seaform squirt into the throttle body a few months ago. The car also gets treated to a trackday blow out every year. Other than that, the inlet valves have had a normal road going existance.