Going through a new front cover setting it up for my engine and decided to study the oiling situation.
I generally do not think that engineers do something that requires more difficult machining for no reason, and I believe this is the case with the front cover.
If you will observe, the oil is fed to the gears by this rather complicated pathway where it comes from the hole visible to the right inside the bottom slot, travels upward, passes into the cavity formed in the slot above, and then travels back down to the gears. The oil then travels out as seen in the picture below.
Pressurized oil leaves through that hole, then makes a 90 degree turn downward into the slot, and to the oil filter.
The Earl Brown mod includes drilling a hole on the opposite (feed) side) that is closer to the bottom face of the oil pump.
I got to thinking and wondered, well, why not just do this:
The colored areas represent where you would just cut a vertical slot. This would allow the bottom hole to feed the pump gears (with a radiused entrance of course) and the exit would be unimpeded. You could even radius the entrance to the oil filter adapter.
Well, I think there is a reason why Buick didn't do that, or drill the side feed hole as in Earl Brown's modification and here's why:
Those lines represent where the oil height in the pump will be at rest (engine off) depending on where the extra feed hole is drilled. The green line represents the stock configuration. Oil will only drain back to the pan until it reaches the bottom of the main passage hole and then stop. This leaves a small part of the gears exposed to air.
The red line represents the oil height with a passage drilled maybe a half inch below the mating surface.
In this angle, the orange line represents the level that would be in the pump when you pull the oil filter off to do an oil change. The hole in the pressure side would only drain fluid in this situation.
The red line represents the level oil would drain back to the pan if both the pressure side and feed side were slotted. The red line also represents the oil level that would exist if you only slotted the pressure side, and did an oil change.
The Earl Brown side feed hole would be represented by an additional line that would depend on how far away from the mating surface you drilled. In the pictures on his thread, that would be only slightly above the red line, and is on the feed side which would drain every time the engine was stopped.
So, the question now becomes, what amount of oil left in the pump is adequate to prevent wear, and a loss of prime to the pump?
Even in the stock scenario, once the oil that is sitting in the pump is exhausted (during cranking) the engine will now have to pull suction on an empty feed passage, one that is empty down to the point of the oil level.
One hypothesis of mine is that GM did this to account for the possibility of someone parking on a right sloping incline which could potentially drain the pump of all fluid and thus lose prime. Another hypothesis is that this amount of fluid would represent a factor in long term wear as the engine would build oil pressure marginally faster each start for the life of the vehicle.
If none of these things are a concern, why don't we just slot and radius the cover as I propose in the photo above?
I generally do not think that engineers do something that requires more difficult machining for no reason, and I believe this is the case with the front cover.
If you will observe, the oil is fed to the gears by this rather complicated pathway where it comes from the hole visible to the right inside the bottom slot, travels upward, passes into the cavity formed in the slot above, and then travels back down to the gears. The oil then travels out as seen in the picture below.
Pressurized oil leaves through that hole, then makes a 90 degree turn downward into the slot, and to the oil filter.
The Earl Brown mod includes drilling a hole on the opposite (feed) side) that is closer to the bottom face of the oil pump.
I got to thinking and wondered, well, why not just do this:
The colored areas represent where you would just cut a vertical slot. This would allow the bottom hole to feed the pump gears (with a radiused entrance of course) and the exit would be unimpeded. You could even radius the entrance to the oil filter adapter.
Well, I think there is a reason why Buick didn't do that, or drill the side feed hole as in Earl Brown's modification and here's why:
Those lines represent where the oil height in the pump will be at rest (engine off) depending on where the extra feed hole is drilled. The green line represents the stock configuration. Oil will only drain back to the pan until it reaches the bottom of the main passage hole and then stop. This leaves a small part of the gears exposed to air.
The red line represents the oil height with a passage drilled maybe a half inch below the mating surface.
In this angle, the orange line represents the level that would be in the pump when you pull the oil filter off to do an oil change. The hole in the pressure side would only drain fluid in this situation.
The red line represents the level oil would drain back to the pan if both the pressure side and feed side were slotted. The red line also represents the oil level that would exist if you only slotted the pressure side, and did an oil change.
The Earl Brown side feed hole would be represented by an additional line that would depend on how far away from the mating surface you drilled. In the pictures on his thread, that would be only slightly above the red line, and is on the feed side which would drain every time the engine was stopped.
So, the question now becomes, what amount of oil left in the pump is adequate to prevent wear, and a loss of prime to the pump?
Even in the stock scenario, once the oil that is sitting in the pump is exhausted (during cranking) the engine will now have to pull suction on an empty feed passage, one that is empty down to the point of the oil level.
One hypothesis of mine is that GM did this to account for the possibility of someone parking on a right sloping incline which could potentially drain the pump of all fluid and thus lose prime. Another hypothesis is that this amount of fluid would represent a factor in long term wear as the engine would build oil pressure marginally faster each start for the life of the vehicle.
If none of these things are a concern, why don't we just slot and radius the cover as I propose in the photo above?
Why do they call these mods the "Earl Brown cover" ?? I have the Buick Power Source and the Jim Ruggles book and they describe these mods long before anyone else ever did them
Also, the hole he recommended drilling to bring the oil into both the top and bottom of the gears was a new thing as far as I know. That was not in the Ruggles book, Free Spirit book, or the Power Source. Now those publications did show ways to reroute the pressure relief outlet to a different spot (such as with a drilled hole or with a KB/Ruggles type booster plate), which supposed has some benefits (though I never really understood just what that was), and Earl said that his suction side hole was doing the same thing, but I don't think that was right. At least that is my recollection - its been several years since I looked at all that stuff. But I used to be real familiar with it.
