How Timing effects Oil changes

A well-tuned diesel is a happy diesel

Words by Andrew Leimroth

Photography by Caravan & Motorhome

Think of engine oil in your diesel as the ‘mop and bucket’ a cleaner uses. Oil doesn’t just lubricate, it must also remove soot particles from in and around the engine and suspend these until the next oil drain. As when mopping a floor, the dirtier the mopping water gets the less clean the mopped floor will be. That’s why regular oil changes are a must in a diesel. Clean oil means a clean engine. Complete combustion also means less soot particles to contaminate the oil. That’s why a well-tuned diesel is part of a good maintenance routine. Over-fuel a diesel and you can make more power with potential additional soot loadings in the oil. Inject fuel too late in the combustion process, and you greatly increase the soot loads in the combustion process.

Extending injector duration in common-rail diesels with chips is an inefficient way of tuning a modern diesel. Not only does the fuel go in late, making a lesser power ‘bang for buck’ change, but this very late fuel leads to high soot loadings in the engine oil.

Because the piston is already on its way down on the combustion stroke, this type of chipping (injector duration) needs to add lots more fuel to get any chance of a serious push on the already descending piston. It’s due to this type of tuning, extending injector duration, that oil service intervals need to be even more regular.

Following along the lines of the manufacturer’s design, the only safe way to tune a modern diesel is through safe monitoring of fuel pressures and adjustment of these pressures with digital precision. If this is done correctly you end up with efficient, complete combustion and a normal oil change interval. Clean oil means all the little areas around bearings, pistons and rings will stay clean and free to move leading to a very long engine service life.

Safe Driving

Andrew