There are two versions of the 6.8 V10 engine. The early engines were first introduced in 1997 and produced 305 brake horse power and 420lbs of torque. This early engine was fitted in the E450 chassis that was used for ‘C’ class American RV motorhomes, amongst many other applications.
In 1999 the Ford 6.8 V10 was used in the F53 chassis. This engine produced slightly more power than the first version, 310 brake horse power and 425 lbs of torque, and was used to produce ‘A’ class American motorhomes. Both of these engines experienced their own problems, which I have documented one of my earlier articles, also they both had 2 valves per cylinder.
The next generation engines were produced from 2006 onwards, they again produced more power and were more fuel efficient and now had 3 calves per cylinder.
All of the 6.8 V10 and the 4.6 and 5.4 V8 engines experience the same spark plug problems. Ford in their wisdom use a two piece spark plug, which when you try to remove it can break. The reason for this is that the carbon builds up on the end of the spark plug, this causes the two piece spark plug to separate at the manufacturing joining, leaving the lower electrode point jammed in the cylinder head. Special tools are then required to extract it.