[nicrobell]

Apparently, direct fuel injected petrol engines can acquire a build up of carbon deposits on the back of the inlet valves. This is caused by crankcase vapours being fed into the inlet system. These oily vapours can adhere to the hot valve and form deposits over time. Older engine designs introduce petrol upstream and therefore tend to wash the inlet valves during the induction stroke thus reducing carbon build-up. I would be interested to find out if anyone has opened a direct injected engine and what deposits were seen. I wonder if Ford have addressed this problem and can offer any advice to reduce the carbon build-up.