Oil starvation under high G loading - opinions and solutions?
05-08-2004, 11:02 PM
#1
Oil starvation under high G loading - opinions and solutions? By high G, I mean approaching 1G ...
Recently, there have been some oil starvation related engine failures attributed to oil starving the pickup tube in the oil pan. How, you ask?
When taking long sweeping turns, the G loading forces oil to one side of the oil pan and then it creeps up the side. Now, realize, revs are at 5K+ typically. So the pump is really sucking a lot of oil at that time ... the worst possible time, actually.
The rule of thumb is to run 7 quarts of oil, filling the motor so high that the P/U tube never uncovers. I will address some findings concerning this a little later on.
Here is the pan fresh off a motor.
Notice a couple of things ... the baffle plate sits about 3.5" off the bottom of the oil pan. It is formed to fit the contour of the pan's deepest section, or "bowl".
With the baffle removed, this is what you see.
Notice how there is some baffleing built into the lower section of the pan. This reduces the amount of oil that sloshes to the back under acceleration and to the front under decelleration.
Now check out a theory:
The red arrow shows how we think the oil will move to one side under side loading and then crawl up the side of the pan, through the small gap between pan baffle and pan wall. This gap is about 1/8" to 1/4" wide.
Our thought process is to keep the oil underneath that baffle for as long as possible.
So, how about this ....
A bead of sealant is run where you see purple. This would mean that the only oil escaping out of the bottom section of the oil pan would be through the pump. A good thing ...
To help drain back, the baffle has an additional hole cut in it where the cross-hatch is. It would be about the same size as the factory hole.
There is some concerns about either or both of these "fixes".
Like, how much of the oil that rises up between the crack, slides back down the crack? Will there be enough "open holes" to adequately handle the oil drain back without the cracks in the sides? Hence the need for additional holes?
I would really like to hear some of your experiences and any potential solutions.
Now, about that oil pan. The large, bottom section is conservatively 11" x 8.5".
We saw a "dimple" in the pan for clearance of #1 and #2 rod caps/bolts. Using that as a point of reference, the large part of the pan is ~4" from this "dimple". So the volume from the "dimple" to the edge of the pan's "bowl" is left unaccounted for, to be conservative.
Just the "bowl" of the pan measures 11" x 8.5". the lowest point of the rod cap/crank is just over 4" from the bottom of the pan.
11 x 8.5 x 4 = 374 cubic inches. A Google search on converting cubic inches to quarts, shows 6.4 quarts. Now, take into account the amount of oil used in the filter, any residual oil left in valleys and oil coolers (if you have one) and the unaccounted for pan volume illustrated above, a 7qt oil change with a filter is very conservative when concerned about the crank sloshing into the oil. 8 would probably be OK, but cutting it close.
Thoughts?
Recently, there have been some oil starvation related engine failures attributed to oil starving the pickup tube in the oil pan. How, you ask?
When taking long sweeping turns, the G loading forces oil to one side of the oil pan and then it creeps up the side. Now, realize, revs are at 5K+ typically. So the pump is really sucking a lot of oil at that time ... the worst possible time, actually.
The rule of thumb is to run 7 quarts of oil, filling the motor so high that the P/U tube never uncovers. I will address some findings concerning this a little later on.
Here is the pan fresh off a motor.
Notice a couple of things ... the baffle plate sits about 3.5" off the bottom of the oil pan. It is formed to fit the contour of the pan's deepest section, or "bowl".
With the baffle removed, this is what you see.
Notice how there is some baffleing built into the lower section of the pan. This reduces the amount of oil that sloshes to the back under acceleration and to the front under decelleration.
Now check out a theory:
The red arrow shows how we think the oil will move to one side under side loading and then crawl up the side of the pan, through the small gap between pan baffle and pan wall. This gap is about 1/8" to 1/4" wide.
Our thought process is to keep the oil underneath that baffle for as long as possible.
So, how about this ....
A bead of sealant is run where you see purple. This would mean that the only oil escaping out of the bottom section of the oil pan would be through the pump. A good thing ...
To help drain back, the baffle has an additional hole cut in it where the cross-hatch is. It would be about the same size as the factory hole.
There is some concerns about either or both of these "fixes".
Like, how much of the oil that rises up between the crack, slides back down the crack? Will there be enough "open holes" to adequately handle the oil drain back without the cracks in the sides? Hence the need for additional holes?
I would really like to hear some of your experiences and any potential solutions.
Now, about that oil pan. The large, bottom section is conservatively 11" x 8.5".
We saw a "dimple" in the pan for clearance of #1 and #2 rod caps/bolts. Using that as a point of reference, the large part of the pan is ~4" from this "dimple". So the volume from the "dimple" to the edge of the pan's "bowl" is left unaccounted for, to be conservative.
Just the "bowl" of the pan measures 11" x 8.5". the lowest point of the rod cap/crank is just over 4" from the bottom of the pan.
11 x 8.5 x 4 = 374 cubic inches. A Google search on converting cubic inches to quarts, shows 6.4 quarts. Now, take into account the amount of oil used in the filter, any residual oil left in valleys and oil coolers (if you have one) and the unaccounted for pan volume illustrated above, a 7qt oil change with a filter is very conservative when concerned about the crank sloshing into the oil. 8 would probably be OK, but cutting it close.
Thoughts?
Last edited by mitchntx; 05-08-2004 at 11:08 PM.
05-08-2004, 11:59 PM
#2
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Forget all that trouble! What the heck are you doing with your car anyway that your pulling 1g into corners and 5-6000 rpm. You must be road racing I would assume. If it was up to me and I was strictly using my car for road races Id go with a dry sump setup, but it costs some bucks. Or just go with Canton Racing there all aluminum road race oil pan with trap door baffling would fit your bill and it would also cost you one too though about 5 of them. I would say your good though if you just run a road race once in awhile for some fun. Good Luck
05-09-2004, 12:20 AM
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For cheap I would say add a trap door baffles to the factory baffle running parallel to the sides of the pan rail as close to the pick up as possible. Another item I would consider mandatory in that type of application would be a Moroso Accusump. This is a device that uses compressed air and a spring to force oil into the engine whenever the oil pressure drops, then when it recovers it will slowly fill the sump back up. It is also equipped with an open/close valve so you can close it before shutting off the motor, and then open it before cranking to prime it before cranking. Thay are also almost mandatory on hard hitting big block drag cars that tend to uncover the pick ups on deceleration after passing through the traps.
05-09-2004, 07:23 AM
#4
The issue with an Accusump setup is where to put it.
Understand ... these cars are still street driven cars. Not yet are they gutted dedicated racing cars.
What we are trying to do is help, not necessarily eliminate, an issue using existing parts.
Understand ... these cars are still street driven cars. Not yet are they gutted dedicated racing cars.
What we are trying to do is help, not necessarily eliminate, an issue using existing parts.
05-09-2004, 08:19 AM
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I would go with a dedicated pan. But short of that, I would drop the bottom down an inch and extend the sides out along the sump and using the factory baffle attach doors to control sloshing around turns. Drill the walls from the factory with a series of holes to slow the oil movement but not stop it. The factory metal baffle extends far enough back to prevent any major amount of oil from climbing up the back. Or, cut the baffle along the factory stands in the rear and install a screen type baffle over the front to allow drain back and stripping. Milidon makes one of the best for the SBC adapt it to fit or get screen similiar to it.I am not keen with the silicone idea in the sump. If a piece comes loose..... it could mean bye-bye motor.
05-09-2004, 08:29 AM
#7
Exhibit E, Canton oil pan
See how it is "sealed" where you proposed to seal the stocker. It is opened up on the right sise however, which is where the oil would go in a left turn.
See how it is "sealed" where you proposed to seal the stocker. It is opened up on the right sise however, which is where the oil would go in a left turn.
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05-09-2004, 08:49 AM
#8
Good points about the sealant. Maybe weld a stock type baffle welded into place? It's stamped steel and wouldn't weld too well to the aluminum oil pan.
Glen, if it weren't for headers and ground clearance, making a bigger pan would be a great idea.
Glen, if it weren't for headers and ground clearance, making a bigger pan would be a great idea.
05-09-2004, 09:16 AM
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Originally Posted by mitchntx
Good points about the sealant. Maybe weld a stock type baffle welded into place? It's stamped steel and wouldn't weld too well to the aluminum oil pan.
Glen, if it weren't for headers and ground clearance, making a bigger pan would be a great idea.
Glen, if it weren't for headers and ground clearance, making a bigger pan would be a great idea.
05-09-2004, 10:12 AM
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This was definitely a problem during the development of this engine for GM and is why they deveoloped a "batwing" oil pan for the vettes...I honestly wonder how many of these failures are attributed to people not running enough oil. I'd like to know if people were actually below factory specs. I've seen it several times in the last year about people drag racing and spinning bearings and come to find out, they were 2qts low! When road racing when the engine is running 5000+, oil consumption becomes an issue...be it PCV or through the rings...Run a few sessions and not add any oil to an engine thats already a little low to begin with=squeak.
Last edited by MyLS1Hauls; 05-09-2004 at 06:15 PM.
05-09-2004, 06:04 PM
#11
Originally Posted by santino04
Forget all that trouble! What the heck are you doing with your car anyway that your pulling 1g into corners and 5-6000 rpm. You must be road racing I would assume.
The Canton setup requires a remote filter. Not ready to go that far, yet.
I recall early on LS1 motors popping on Ax and RR circuits. Everyone said that it was predominantly long, sweeping, high speed left hand turns. That figures into exactly what I've witnessed.
Notice the huge gap in the pan's baffle tray around the oil level sensor? Also as the oil climbs, the "hump" stamped into the stock baffle will act like a funnel?
Also, notice the Canton pan Chuck linked to? Notice how the baffle tray is sealed all the way around (welded) and notice no hump? The baffle appears to be within a 1/2 inch of the lip, where the the stock baffle is 2 or more inches from the lip of the pan. so, a sealed edge and a deeper sump ...
Any speculation as to why the partitions in the bottom of the Canton pan are facing differently than the stockers?
Any reason to keep the oil level sensor? Remove it to flatten and seal up the right side better. And that would be a great place for an oil temp sender.
05-09-2004, 06:31 PM
#12
Originally Posted by mitchntx
You must realize, there are some of us who use all 3 pedals , not just the one on the right.
The Canton setup requires a remote filter. Not ready to go that far, yet.
I recall early on LS1 motors popping on Ax and RR circuits. Everyone said that it was predominantly long, sweeping, high speed left hand turns. That figures into exactly what I've witnessed.
Notice the huge gap in the pan's baffle tray around the oil level sensor? Also as the oil climbs, the "hump" stamped into the stock baffle will act like a funnel?
Also, notice the Canton pan Chuck linked to? Notice how the baffle tray is sealed all the way around (welded) and notice no hump? The baffle appears to be within a 1/2 inch of the lip, where the the stock baffle is 2 or more inches from the lip of the pan. so, a sealed edge and a deeper sump ...
Any speculation as to why the partitions in the bottom of the Canton pan are facing differently than the stockers?
Any reason to keep the oil level sensor? Remove it to flatten and seal up the right side better. And that would be a great place for an oil temp sender.
The Canton setup requires a remote filter. Not ready to go that far, yet.
I recall early on LS1 motors popping on Ax and RR circuits. Everyone said that it was predominantly long, sweeping, high speed left hand turns. That figures into exactly what I've witnessed.
Notice the huge gap in the pan's baffle tray around the oil level sensor? Also as the oil climbs, the "hump" stamped into the stock baffle will act like a funnel?
Also, notice the Canton pan Chuck linked to? Notice how the baffle tray is sealed all the way around (welded) and notice no hump? The baffle appears to be within a 1/2 inch of the lip, where the the stock baffle is 2 or more inches from the lip of the pan. so, a sealed edge and a deeper sump ...
Any speculation as to why the partitions in the bottom of the Canton pan are facing differently than the stockers?
Any reason to keep the oil level sensor? Remove it to flatten and seal up the right side better. And that would be a great place for an oil temp sender.
Pussies
Accusump, or a new pan.
Remember, 1 G, is 45* in the pan. If its FULL, you should have NO problems.
I was running circles around all of you and I had NO Issues just the way you are set up
05-10-2004, 09:23 PM
#17
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recall early on LS1 motors popping on Ax and RR circuits. Everyone said that it was predominantly long, sweeping, high speed left hand turns. That figures into exactly what I've witnessed.
05-10-2004, 09:49 PM
#18
It's really simple. It's a dry sump, and no you don't have to sell your soul to own one. I have some of the hardware for this in boxes, new, along with my Stack guage, just haven't had the mental capacity to deal with any of it, to install it. The place is Armstrong race engineering. They have a special LS1/LS6 dry sump pan. With what your doing performance wise, you've been on wing and a prayer to last this long. There's help, and no I'm not talking about Betty Ford. Check out their neat valve covers also.
http://www.drysump.com/pan1a.htm
http://www.drysump.com/index1.htm
http://www.drysump.com/pan1a.htm
http://www.drysump.com/index1.htm
05-11-2004, 06:33 AM
#19
Originally Posted by sawedoff
It's a dry sump, and no you don't have to sell your soul to own one.
Interesting site. It appears that either a "special" ATI damper is required or removal of the AC is needed in order to drive the pump.
05-11-2004, 07:01 AM
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I really wish Mikey from Rapid would see this post. He's building the motors for Phoenix performance's new rides. They used to run LS1 Firebirds, but recently switched to Vette's. He may have a trick that you're looking for Mitch. I'm curious to find out myself.
Tony
Tony