November 2020

BY Frank Massey I have always focused on topics that have developed through our workshop, the main reason for this is authenticity and integrity. However, it is not always possible to be fortunate enough to have topics with enough content for publication. So, this month we are going to have a banquet of multiple stories of interest where you can spin the table and pick your favourites. First topic An Audi S3 came in for a MIL light and poor running complaints. Initial serial interrogation concluded camshaft correlation errors. This has significant concerns with this 888 power plant, as it has variable inlet and exhaust control as well as exhaust valve lift. This is a very powerful and usually competent engine, but unfortunately the vehicle was purchased recently with a known poor service history. This is an absolute no-no with today’s technology. Having conducted a basic health assessment, and noting actual and specified camshaft position errors, it was decided to replace the oil and filter. I must add here that it ran much worse afterwards. Historical experience has shown problems with chain jumping and oil filter cartridge collapse. This engine employs a variable displacement oil pump providing 1.8 bar at low speed and 3.8 at higher load. It is also PCM- mapped. I am not a fan of such a low oil pressure especially on crank start. My Seat Cupra has on several occasions displayed slight chain tension noise on start up. Bear in mind I replace the oil every 3,000 miles, and it has only done 18,000 miles. Additional thoughts should be given to Stop/Start; All engines will suffer gravitational oil drainage when stopped. We are now increasing this multiple times. Not a good idea really. We have also seen oil filters collapse shedding filtration media particles into the oil galleries. The timing cover was removed, visual evidence shows surface bearing damage to both the cams and alloy cover. This evidence confirms both a boundary layer lubrication failure and metallic swarf erosion. In my opinion this is sufficient evidence to reject the entire engine, subject to a total strip-down. Please refer to; Fig.1, cam sprocket and 24 AFTERMARKET NOVEMBER 2020 TECHNICAL www.aftermarketonline.net A BUFFET OF ERRORS We hope you brought your appetite with you this month, as Frank has laid on a veritable feast of technical issues for you to chew through Fig.1.888 chain guide and camshaft showing contact wear Fig.2 cam cover showing exessive wear Fig.3.888 cam cover & position sensors Fig.4 fuel pump relay on right Left: Fig.7 a6 engine