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

Somewhat of a thread revival, but it seems like a good place to share my recent experiences...

Having a 2017 GDI engined Plus 4 with nearly 25k miles on the clock, I decided to explore what the inlet valves looked like, suspecting from what I've seen online that they might be getting gunged up with oily sludge and carbon from oil being burnt on.

I invested about £20 in a basic borescope that plugs in my phone and explored the combustion chambers via the spark plug holes.



There was evidence of what I considered to be normal light combustion deposits, but with the aid of the right angle mirror attachment I could see some build-up on the back of the inlet valves, albeit with rather dubious quality images:



So I decided to properly explore by removing the inlet manifold, very much informed by Robert's excellent video guide. Some of the connections are tricky to get to and undo, especially those underneath the manifold - the endoscope came in very handy for seeing into otherwise "blind" areas. Getting the socket on to the last bolt underneath would have been even more difficult without it (and I'm not looking forward to putting it back!)

But now it is off and the results are similar to what Robert found - but worse, as my engine has lots more miles. This is cylinder 2, but they are all much the same:




However there is better news as I am well on the way to cleaning them up, quite satisfactorily I think:



After looking at a number of YouTube videos about how to best clean inlet valves and ports, I assembled a can of Holts EGR and Carb Cleaner together with various tools such as an engine cleaning brush set and a set of pick tools:





The EGR cleaner seems to do a good job of dissolving the oily/carbon build-up and with some laborious scraping and brushing, then mopping out with paper towels, finishing off with a good blast with a long-nozzle airgun achieves a reasonable result (not quite as good as walnut blasting but much cheaper!). The usual caveat of only working on ports with the valves closed, apply! A ratchet socket on the crank at the front turns the engine over (clockwise only) easily enough with the spark plugs removed and coils refitted to avoid debris falling into the cylinders.

I plan to fit an oil separator to avoid the issue recurring. I'll try and update with that later.