Focus RS 9000 Mile Checkup

With our RS coming up on 10000 miles and a year of development and (hard) driving, we thought it would be a good idea to borescope the cylinders and see how things look. This is a 2016 September build and the car has definitely been put through its paces on both the track and street.

The good news is that things look great! Spark plugs show the correct heat range (we run a step colder) and even burning across all the plugs.

Digging deeper into each cylinder we see that the pistons have the usual carbon buildup. We also see how effective the bowl design is at directing fuel and preventing it from being projected on the cylinder wall. You can see in the image below that the fuel spray is well contained within the center bowl (and this cleans it of carbon buildup). Keeping fuel off the cylinder walls prevents them from being washed down and oil dilution.


Below is a video of one of the bores. The cylinder head gasket is the line in the center of the image. We checked all cylinders and none showed any signs of deterioration at this level. The black staining you see on the piston deck is from carbon deposits and the piston rings not coming up high enough to scrape it off the cylinder wall. This is normal.

Here’s to 10000 more! We will keep you all posted. CheeRS!