Here's something I had written up for my website, and thought I'd share with you guys.

Oiling System:

Preface: The 4.6L/5.4L modular engines use a gerotor type oil pump to supply the oil pressure necessary for these engines. This type of pump utilizes two separate gears, one of which is spun by the snout of the crankshaft. This is the smaller gear located in the middle of the pump housing. The larger gear is spun off the middle gear and is located inside the pump housing. The oil pump housing is made of aluminum and can be affected easily by debris in the oil. If this occurs, galling of the pump housing will happen and this increases the clearance between the tip of the internal gear and the housing.

There have been two different oil pumps used on factory modular engines. The first one being the 2V pump that features a 0.470” thick gear set, and the other being the 4V pump featuring a 0.510” thick gear set. The design of each pump and their respective housings are identical. The reason for two separate oil pump designs is quite simple. The smaller thickness 2V oil pump was used on all iron block engines, while the larger “HO” oil pump was used on the 4V aluminum based engines. Aluminum based blocks expand with heat much more rapidly than Iron based blocks, and as a result the clearance in the main bearing journals expand more. As the main bearing clearance expands, more oil will leak past the bearings and back into the pan. To correct this issue, the use of a higher volume pump is required. The 4V high output pump is simply a design to help increase oil flow on aluminum based engines, such that the oil pressure in the oil galleys will stay high enough. The iron based 2V engine blocks do not require the same amount of oil flow as their aluminum counterparts, and therefore can withstand using the lower volume pump.

Now it may seem that in the case of oil flow, more is better. This is not always the case, as too much oil flow can cause issues of cavitation and power loss. The factory oil pumps were designed to supply enough pressure for all aspects of the engine at hot oil temperatures. The oil pump was also designed to operate with the internal pressure relief valve in the closed position. In high performance engines, many people assume that the use of a “H.O.” large volume oil pump is required. This is not always the case, as the use of a large volume 4V pump on an iron block can cause the internal relief valve to stay open at moderate to high speeds. When the relief valve is open, you run the risk of the oil bypassing through the valve and back into the suction side, which can lead to cavitation. Cavitation is the cause of oil aeration (aka air in the oil system) and can wipe out bearings in a short amount of time.

Aftermarket Upgrades:

Since the modular oiling system uses a wet sump type system, the only choices you have to upgrade are with billet oil pump gears. The factory oil pump gears, found in the pump housing are made of powder metal. These gears are easily susceptible to high torsional loads on the crankshaft. As torsional vibration increases on the crank snout, the more load the pump gears face. Due to their weak structure, they are prone to cracking and breaking. A set of billet gears are made with a Rockwell hardness much greater than the factory gears, and as a result can withstand much more load. The concern with aftermarket oil pump gears is the “tip to tip” clearance tolerance. Factory gears are found with a .002” clearance, while many of the aftermarket gears can be found with a .008-.012” clearance. The result of a larger clearance is lower overall efficiency and pressure. If any aftermarket gears are to be installed in your oil pump, I would strongly suggest measuring the clearance to ensure your set is within spec.

It should also be noted that the factory oil pump and gears were designed to withstand the vibrations from the factory harmonic balancer. The use of a smaller diameter balancer or one with inadequate vibration dampening can increase the risk of oil pump damage. Many of the aftermarket under drive pulley setups do infact increase this risk

 

What is your website cause I have seen both of your writeups before?

 

I've posted them on this website in specific threads before, as well as other forums over the years.