So Fix it

Whenever you decide to take on the often daunting task of rebuilding any engine, whether its a large, complex type of engine or a lawn mower, the most important part of the undertaking is a thorough knowledge of engines in general and how they function. This is especially true when the engine being rebuilt is the Ford 4.6, or the F6AE. When these engines were built, they were built in two locations and with two specification settings. The fact that the 4.6-liter engine has been used in a number of Ford vehicles is another factor in the need for a thorough knowledge of the specific engine being rebuilt and the specifications of each different component of the engine itself.

Romeo v. Windsor

The two plants that manufacture the Ford 4.6L engine are erred to as the Romeo and the Windsor plants, because of their geographic location. The difference between the two manufacturing facilities makes all of the difference for rebuilding the engine, because the two plants built different models, which also included manufacturing two forms of the same engine. Beyond that, the plants also manufactured two types of 4.6 engine, erred to as PI and NPI, or Power Improved and Not Power Improved. These two headings directly affected the manner in which the components of the engine were built and to what specifications they were adhered. You must make sure you distinguish the difference before you begin to rebuild so you can order the right parts.

Rings and Gaskets

Because of the specifications to which the engines have been built, you must take into consideration the fact that the gaskets and the rings that are used within the engine to create sealed components come in different sizes and are made of different materials. This means that a specific O-ring or piston ring cannot be purchased for the engine unless the specific set for the engine being rebuilt has been established.

Model Type vs. Model Year

Because of manufacturing demands and supply-chain requests, the engine model that was built for a specific make and model may have changed from one year to the next, meaning that just because a 1999 model was built with a Romeo PI 4.6 doesnt necessarily mean that the year 2000 model was even manufactured in the same plant. The next model year could be altered from a Romeo PI 4.6 to a Windsor NPI 4.6, depending on manufacturing needs. This should always be the first determination you make when deciding to rebuild a 4.6 engine.

Same as New

A transmission rebuilt by a competent mechanic should be as clean and serviceable as a new unit. Check the service interval recommendation for your vehicle, and follow it. Depending on the make and model of the vehicle, the recommended service interval may range from 25,000 to 100,000 miles; some cars may never require this service.

Change at 5K

Transmission rebuilds can become expensive; replacing your transmission will cost even more. For peace of mind, if for no other reason, change the transmission oil and filter in a rebuilt transmission after 5,000 miles. Some shops require a 5K oil and filter change as a condition of their warranty and will include this work at no additional charge.

Bottom Line

Change a rebuilt transmissions oil and filter at 5,000 miles---especially if not doing so will void the warranty. After that point, rely on the manufacturers recommendation for maintenance intervals.