There have been consumers complaint about 4.6L V8 248HP for very power gas mileage and grossly under powered and more reviews on 2008 F-150 4.6 L V 8 again for the same problem with gas mileage.
If your truck is not a 4.6 L, The rings may do not seal well and may allow excessive blowby and reduce the engine power 10 to 20 horsepower or more. Blowby also dilutes the oil in the crankcase with fuel and combustion byproducts, which can shorten the life of the oil and lead to premature engine failure. It will also increase crankcase emissions and the load on the positive crankcase ventilation (PCV) system. So one way to check ring sealing is to measure blowby.
Less blowby means more usable horsepower. Being able to baseline the actual blowby in an engine means you can then go back and try different ring configurations, ring types (conventional or gapless), different ring end gap settings and cylinder wall finishes to see which combination gives the best seal and the least amount of blowby.
Measuring blowby has been one of the best kept secrets with performance engine builders because it allows them to see how well the rings are or are not sealing. It also allows them to detect any ring flutter that may be occurring within a particular rpm range, and to then change the mass or end gaps of the rings to minimize the problem.
Ask your dealer to perform the blowby test.
Sunday, April 11th, 2010 AT 6:34 AM