Oil pump cover mods - something to consider

Pablo

Active Member
Joined
Sep 12, 2004
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.

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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.

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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:
bottom.jpg


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:
back.jpg


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.
front.jpg


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 just radius all the passages and spend a bunch of time setting pump clearances. A stock timing cover is adaquate (untouched) for just about any engine, though. I have a stock timing cover on an on center StageII with a TA pump cover for hose attachment and that sucker made over 150 psi at idle!!! I found a design flaw in the pressure regulator circuit. A stock oiling system works fine.
But........ I know.......I know......we all strive to make everything better.
Double check the oil pump drive shaft to cam sensor alignment. I have had them bad on the aftermarket covers. (That cost me a complete tear down to find the metal generator in the oil. It ate the cam sensor lower bushing)
 
The traps are indeed built in to prevent loss of prime for all different situations that could be encountered........parking on hills, sideways tilt and so on......I spend a fair amount of time blending, radiusing, gasket matching and adjusting gear end clearance.......nothing else is really needed but I can see the value in adding the extra hole on the suction side......been 7200 with solid roller lifters and a gm cover with no oil related issues.......if you decide to modify yours let us know how it works out.....
 
Thanks for the replies guys. I ended up cleaning up the casting flash, radiusing corners, and drilling out the pressure passages to 1/2". I don't think I will drill the side feed or slot cut the pressure and feed sides. Doesn't seem worth the risk to me. I ran an HV pump setup before this and never had trouble with oil pressure, and from your experiences, I don't expect trouble with the standard pump setup.
 
I did my cover about 5 years ago and spent a fair amount of time looking it over before doing any modifications.
I also was concerned about the possibility of uncovering the gears or loosing prime while the engine wasn't running.

My concerns may have been unfounded but In the end I decided to radius the path to the point that the gears would have no more than 1/3 of their overall length exposed just in case there was some sort of bleed down.

There is also the possibility that oil would stay in the gear cavity no matter where the hole was located due to some sort of "thumb over the straw" affect going on that we haven't considered.

There is so much to consider when building a motor that sometimes it gets counter productive for me........I spend way too much time trying to redesign or overthink something that probably was more than adequate the way it was.
 
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Doing one of these today. I don't do the Earl Brown mod. I like GM covers, and I really like the TA cover a lot less work needed. Good stuff. I open passage and smooth things out. Set up the end play tight, gasket match etc like the above posters. Never a need for anything thicker than 5w-30 either.
 
I keep reading these oil pump mod posts and I am confused! :confused: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:eek:
 
I keep reading these oil pump mod posts and I am confused! :confused: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:eek:
Not sure, but my hunch is because over on the other board he took the time to do a very detailed write up. I have books out in the garage that talk about the same mods and no mention of Earl....lol.
 
I keep reading these oil pump mod posts and I am confused! :confused: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:eek:

Actually Kevin these mods were done on the Buick V-8 engines before the turbo V-6 engines as TA was doing "mods" in his garage on the timing covers!

The Buick 350 V-8 uses the identical cover as the V-6, and the 400/430/455 Buick V-8 is very similar.

When GM discontinued the big-block V-8 cover, Mike had a casting made with improvements and he made changes as well internally as he machines them in-house.

The TA V-6 timing cover has many changes and improvements over the stock turbo cover to improve oil flow and pressure, and actually the original turbo Buick does the job very well.

Many oil pressure issues are blamed on the pump which is usually when someone "messes" with them, or the issue is some where else in the engine?
 
Why "Earl Brown"? I would agree with the above posters - he did a really nice detailed write up on it :) 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.
When I was going through my engine back then I was intimately familiar with all those mods, and if I had known about or thought about drilling that hole, I would have done it. But I was done putting mine all together by the time he posted that.

Like the other posters I did lots of porting and radiusing and what not to get the best oil flow I could, and I can't prove that it did any good, but it comforts me :) If I listed everything I did to my oiling system it would be quite a laundry list.

One thing I can say is that the oil pressure problems I actually have experienced seemed to be due to #1 cam bearing issues. IMHO I would say that getting that set up right will do as much or more for long term oil pressure. A dedicated drag car might not need as much attention there, but if you plan to put some serious miles on your engine, I think paying attention to cam bearing hardness, groove vs. no groove in the #1 cam journal, and so on, will really make the difference when you get 20k miles down the road.
 
I keep reading these oil pump mod posts and I am confused! :confused: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:eek:
The Earl Brown mod is drilling the hole which gets rid of a 180 degree turn that the oil has to maneuver on it's way to the gears.
The Ruggles contribution to the Buick oil pump is the booster plate which creates a flat surface for the bottom of the gears to ride against. This surface eliminates a large cavity that is used to allow bypass oil from the pressure regulator valve to re enter the pump at the bottom of the gears. Since the plate has no cavity,the pump cover is modified to allow the bypass oil to re enter the oil intake stream. The removal of this cavity causes the pump to become more efficient.
 
Lee Thompsons old blue car ( belongs to a buddy of mine now) made 38psi at idle. It's knowing how to set clearances. Not just the pump, but bearings as well. My Stage 2 was built with .0015 mains .0015 rods .Yes it's a little tight for most but put a jacked up pump in it and it'll have junk pressure. I'm running a TA cover I got from Nick complete( TA pump over and timing cover. Many thanks again for the deal and service Nick. I re checked clearance and used TA plastic type shims. Should have 35-40 at hot idle. Lee's S2 has stock style stuff not the Duttweiler style I'm running . All three holes are plugged off on mine. Point is all the tricks people do may help, but why not just get a stock HI QUALITY timing cover and just set it up right. I wouldn't touch the TA. Everything is nice to begin with. Buy a junk Gbody parts cover you'll port for days. Been there.
 
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Actually Kevin these mods were done on the Buick V-8 engines before the turbo V-6 engines as TA was doing "mods" in his garage on the timing covers!

The Buick 350 V-8 uses the identical cover as the V-6, and the 400/430/455 Buick V-8 is very similar.

When GM discontinued the big-block V-8 cover, Mike had a casting made with improvements and he made changes as well internally as he machines them in-house.

The TA V-6 timing cover has many changes and improvements over the stock turbo cover to improve oil flow and pressure, and actually the original turbo Buick does the job very well.

Many oil pressure issues are blamed on the pump which is usually when someone "messes" with them, or the issue is some where else in the engine?


I agree with Nick and don't try to out guess the GM engineers which are smarter than me, the T/A cover is a quality piece as well as the oil filter adapter offered. The worst I ever seen were the Chinese knock off covers .
 
GM was designing for grandmas Electra. Way different parameters that what guys like us do to it a quarter mile at a time. It is amazing the wide range of things it can handle.
Not everyone can just plunk down a card and buy the t/a piece. As great as it is guys like me with a family and such would save for years to put that into the build. The used stuff and tricks get us low budget guys by. Do we do it on borrowed time, of course. But it is still a fun time making passes.
I.love living vicariously through some of the high dollar stuff posted, but my reality is beanies n weenies, so I port the used stuff.

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For an engine with a crappy oiling system,we sure don't seem to ever see pictures of bearing failure caused by oil starvation. Mostly we see evidence of crank flex and/or detonation.

I don't believe for a second that my 700 hp engine would suffer any damage if I removed my booster plate. I do,however,believe that I will be changing head gaskets in the future.

I wonder why I believe these two things?
 
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