Fords V10 6.8 litre (413 cubic inch) engine used with the F53 motorhome chassis (‘A ‘class), and the E450 chassis (‘C ‘class), is part of the company’s “Modular” engine family. The Triton V10 was introduced in 1991 and is still being used today.
This engine represents large evolution of design. One way is to think of the V10 is a 4.0 litre V6 engine with four extra cylinders, or as a 5.4 litre V8 with two extra cylinders, this was something that was used many years ago with motorbikes, for instance ‘Beneli the Italian’. Motorbike manufacturers of the late 1970s took a four cylinder Honda 500cc engine and added two cylinders to it, in fact it was half of another Honda 500 to make the 750cc straight 6 engine.
One of the main faults with the early V10 engines (1999 – 2005) was that the spark plugs could blow out of the cylinder head. Ford use a cast iron engine block with an overhead cam aluminium cylinder head design, that uses centrally mounted spark plugs and waste spark ignition.
The aluminium cylinder heads on the two valve per cylinder engines built in the companies Windsor Ontario plant, have a fatal floor in the spark plug threads. The cylinder head being of soft aluminium does not have much inherent strength in the first place, and also expands at a different rate to the steel spark plug threaded into it.
Ford put the V10 spark plug at the bottom of a 5 inch deep well and only allowed for about four threads worth of spark plug engagement in the cylinder head.
After repeated heat cycling the spark plug welds itself to the threads weakening the material. The end result of this design flow is that the rear most sparks shoot out of the cylinder head while driving or get stuck while trying to remove them, and when hard steel sticks to soft aluminium, the aluminium will initially give way first. This makes the cylinder heads spark plugs strip clean out, leaving a small hole and no way to re-install a new spark plug. Also this failure can occur when removing the spark plugs for renewal.