NEED HELP 4.2 Atlas I-6 oil pan mod?

damifino

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Oct 28, 2018
11
North Carolina
I do not have a donor engine (yet) so I post this question in hopes someone can provide a little insight. The overall height of the 4.2 is taller in stock form than my potential application will allow. How much clearance can be gained by modifying the oil pan into a road race style wet sump pan (sump additions on both sides of pan to maintain capacity while removing all the pan depth possible). Fabbing, welding and machining of pan mods is not a problem for me. All I need to know is if the depth that can be removed is worth investigating further. 4.2 Atlas into 1972 Datsun 240Z.
 

mrrsm

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You have two problems to overcome... at least:

(1) The GM Atlas 4.2L LL8 Engine moves just over 11 Gallons of Oil Per Minute at a minimum of 12 PSI and a maximum of 65 PSI. The Stock Crankcase-Oil Pan Volume is (7) Quarts of Mobil1 5W-30 Motor Oil in the Deep Sump. Unless you have an arrangement where there is enough room just below the very narrow Oil Pick Up opening screen... the Gerotor Oil Pump will starve for enough oil to scavenge if it is configured without enough clearance room to allow the Pump Suction to work right.

As an inverted example....Think of the Small Drain in the bottom of a Topped Off Bath Tub as an example of just how very long it takes for one that full to actually empty itself out if the Stopper is not lifted completely clear of the opening.

If you starve the Gerotor of the much needed Oil Flow by restricting its open access to the larger volume of Motor Oil... it will pump what it can into the top of the engine ...and quit when it simply cannot get the oil in through the Pick Up Screen fast enough...like squeezing down on a Soda Straw.

(2) The Lower Crankcase of this Engine is one Hell of a Big Solid chunk of Aluminum that offers much needed structural strength to maintain the proper Block Rigidity and keep the walls of the Engine Block square enough to hold control over one of the Longest Crankshafts around.

This much needed "Beam Strength" is further enhanced by the presence of a Cast In Tube that not only allows for the passage of the Front Wheel Drive Axles and Front Suspension and Drive Line Hardware hung on either side.... but by its very presence is also a solid contributor to keeping the Bottom End well supported.

You can use the Hydraulic Fluid Dynamics written by Bernoulli to calculate what the Inner Diameter sizes of Modified or Adaptive Oil Pick-Up Tubes you might need to add to the single Tube in the stock motor and spread the demand created around to a few additional pick up tubes welded in a tree like fashion ...laterally providing the added entry ports needed to keep the Gerotor Oil Pump replete with Fresh Oil.
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Check with @limequat . He fit one in a Supra, turbo no less. He spun a bearing recently though and is looking for a replacement.
 

damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
You have two problems to overcome... at least:

(1) The GM Atlas 4.2L LL8 Engine moves just over 11 Gallons of Oil Pere Minute at a minimum of 12 PSI and a maximum of 65 PSI Per Minute. The Stock Crankcase Volume is 7 Quarts of Mobil1 5W-30 Motor Oil in the Deep Sump. Unless you have an arrangement where there is enough room just below the very narrow Oil Pick Up opening screen... the Gerotor Oil Pump will starve for enough oil to scavenge if it is configured without enough clearance room to allow the Pump Suction to work right.

As an inverted example....Think of the Small Drain in the bottom of a Tub as and just how very long it takes for one that is full to actually empty itself out. If you starve the Gerotor of the much needed Oil Flow... it will pump what it can into the top of the engine ...and quit when it simply cannot get the oil in through the Pick Up Screen fast enough.

(2) The Lower Crankcase of this Engine is one Hell of a Big Solid chunk of Aluminum that offers much needed structural strength to maintain the proper Block Rigidity and keep the walls of the Engine Block square enough to hold control over one of the Longest Crankshafts around. This much needed "Beam Strength" is further enhanced by the presence of a Cast In Tube that not only allows for the passage of Front Wheel Drive axles and suspension hardware.... but by its very presence is a solid contributor to keeping the Bottom End well supported.

You can use the Hydraulic Fluid Dynamics written by Bernoulli to calculate what the Inner Diameter sizes of adaptive pick-up tubes you might need to add to the single Tube in the stock motor and spread the demand created around to a few additional pick up tubes welded in a tree like fashion ...laterally providing the added entry ports needed to keep the Gerotor Oil Pump replete with Fresh Oil.
Thank you for the info. Very helpful. Those obstacles are easily overcome if enough pan depth can be removed to suit my purpose. So a 2 wheel drive pan is the same as 4wd pan?
 

mrrsm

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Yes... The Two Wheel Drive Pans are Identical in their Designs ....for the very same requirements of additional structural strength and integrity, In the Four Wheel Drive Configuration... the Crankcase is merely acting as a pass through mount for the suspension drive-line that bolts onto both sides...with a Carrier Bearing and CV Jointed Axle on the passenger side...and the Transfer Case and 'Shorty Drive Shaft and U-Joints plugged into the TC Case on the driver's side...likewise plugged into a hollow cavity and bolted up for support. No internal Engine Gearing or Rotating Assembly Components ever touches that additional 4WD Hardware.
 
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cornchip

Member
Jan 6, 2013
637
The transmission bell housings are one piece as well and might also dictate how high you'll need to mount your engine.....including your front cross member. I'd be surprised if you'd even find it necessary to bump side ways for capacity. I made a pan that holds 7 liters and it's bottom is level with the lowest edge of bell housing. I still have a few pictures on my PC from vortec4200.com showing a typical modified TB oilpan. I believe it's the simplest option.

y4m7CfeLTBMXO_29nkuqduPqL9PtyJRH6aP_nhNO4EI-qXYf-1-r9IcWWAoAXqP5mu01IPqwMNxwWC5Yf1ZBmGbS_mSrSKA6jNRRsUjDhyhid6qPARJN2Ii1AZ20MO1TjWqoKZt-vncaFkjAMBg6ZKIGwod21rr2mXRDcEB53n9Il-dTEJZUJGsvmVJMtSAKaeyB3sasKXZAP5KztwdfST97Q


y4mjp-mZWoPwvEc53fZpxxqHBLtGZEQJ2Dw0wqFicPuWBml6AWAkceQZMo_9bWlR1Y2eyY_skETuz6PYjm901TDcWGlcHG53GvnRs0PnSda4BLHHxTf7ROmNTTFRpx9xLKDhdm01Sl_G3ZiORlMdjCg9gGhaFK3Cnb4ud3PMDlCSuGnScyDfLcf545xrKrgYH4eOXI1opCZ5t9cy9ixWaq_QA


y4md_zSVaBZpughURHnaaGlgTaGRUkklbyrmT37_KZAtSbwDrYQojnrbtpJk1cXAvOZ3MBPpw1rWWs5IRo6yw-jA-Q9E4i1GB90BDVw7UJafJr4W8rzwRadBdiD4B4BWj0r4z7LXWJjpNu7SckHkTrVUSgFvf9c6L0mi4EoxkFx_dZdUHcXrgxthTqobTFqFLsxmhtpCoVI7A2_V7a78XJOOg


y4mFRSz-KdAQifghW3MQT2RPg5xzD6pmJnQ5482c2SQMbbxuAYUCNx7vM7c5J5mXOAkNTz4zyw3n5Bceik_MW8yvpnxZQm9LC7KBW23CVQT9JeTMCeCL3w97inWz1a-FcsV9WztZBvzQi84xcv0q42QxhklOUSzcYAnwSaBlxgQhGyAHRm5suZIr3XozoV2qbw8lE1s3WzpZz1l4lfKyoI8kQ
 

damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
Well it kind depends on where your crossmember hits the pan.
I wish vortec4200 was still up, because Denny had some excellent pics of his fabbed pan. They may be on thirdgen.org

Yup, here they are: scroll to post 11 you'll get your answer.
https://www.thirdgen.org/forums/engine-swap/608490-autorocs-turbo-vortec-4200-a.html
Perfect, that's what I have been wanting to see. Not really concerned about crewmember. Just wondered how much I can take out of the sump. Thanks
 

mrrsm

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Some Food For Thought...

For the sake of making the most out of any much needed design changes in the COMPLETE Oiling System that essentially moves the Source of the Oil a very considerable distance away from the previous Pool of Oil that was closer to and well below the Gerotor Oil Pump... much concentration has to be given to the Re-Design and Brazing Up of a Larger Alternative Oil Pick Up Tube-Screen.

In the same manner that " A Shorter Straw is an Easier Draw" for drinking Sodas... The larger the Inside Diameter the Straw has... the easier it is to vacuum up any fluid (up to a point). With the additional Length of Pipe similar in design to the one @limequat added in to the modified design of the GM 4.2L Oil Pan for his Supra 4200... comes the need to also install a Non-Stock, Wider Mouth Pick up Tube to address allowing an easier path and greater, unrestricted volume of Motor Oil available for the suction performed by the Gerotor Oil Pump... so very far away from the Oil Sump.

This On Topic Link will address all aspects of this problem...with the topic of increasing the size of the Oil Pick Up Tube Screen portion to assist in allowing the Gerotor an easier time of trying to get the Oil out of the Modified Sump...and up into the Innards of the Engine. Many technical issues are covered in this article that might explain the Connecting Rod Bearing Failure at the very back portion of the Engine due to Partial Oil Cavitation leaving those Bearings naked when Bubbles formed during periods of the displaced Engine Oil not being able to travel back into the Sump fast enough to replenish the Gerotor Pump. Also.. Due to its largely lateral position of the Oil Piping... this would invite the presence of any Air being sucked in with Motor Oil to float to the surface of the Oil traveling back to the Gerotor after bubbling up to the upper inside area of that Long Tube:

http://www.enginebuildermag.com/2009/06/oil-pump-technology/

...and this is a Link to @limequat 's original work with photos showing the modified design:

https://forums.trailvoy.com/showthread.php?t=51636&page=1

And to answer the Question of "At What Height should the Oil Pump Pick-Up Screen be Set At for Proper Performance?".... Here is George Richmond from Melling describing the typical Oil Pick-Up Screen set up in V-8 Engines that may be worth following if a GM V-8 Oil Pick Up Screen and Tubing are chosen for this adaptation down inside the Modified Oil Pan of an LL8 Engine:


By now,,, some of us are asking the Question... "So What Bobby... Big Deal... How much Harm can Bubbles be with so much Oil getting Pumped through the Engine Block and into and around the Bearings?" The answer is dramatically emphasized in this demonstration of whether or not The presence of Gas Bubbles in a Liquid Medium will Reduce the Hydraulic Pressure nearby enough to say... Sink an Ocean Going Vessel. The important issue to recognize here is that Reliable Engine Oiling is singularly dependent upon this One Principle:

"All Liquids Are In-compressible..."

This matters a Great Deal because if Air Bubbles get Mixed in with In-compressible Motor Oil... it is the BUBBLES that will compress and reduce the Volume of Oil present in between the Bearings and the Outer Crankshaft Journals... and when THIS phenomena occurs... The Bearings are exposed to Metal on Metal contact and very soon afterwards will Over Heat, Expand and seize to the Outer Crankshaft Journals... spinning inside of the Aluminum Block and ruining the Motor. If you don't think these principles are Universal when it comes to the Physics involved... just watch what can happen:

 
Last edited:

damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
Some Food For Thought...

For the sake of making the most out of any much needed design changes in the COMPLETE Oiling System that essentially moves the Source of the Oil a very considerable distance away from the previous Pool of Oil that was closer to and well below the Gerotor Oil Pump... much concentration has to be given to the Re-Design and Brazing Up of a Larger Alternative Oil Pick Up Tube-Screen.

In the same manner that " A Shorter Straw is an Easier Draw" for drinking Sodas... The larger the Inside Diameter the Straw has... the easier it is to vacuum up any fluid (up to a point). With the additional Length of Pipe similar in design to the one @limequat added in to the modified design of the GM 4.2L Oil Pan for his Supra 4200... comes the need to also install a Non-Stock, Wider Mouth Pick up Tube to address allowing an easier path and greater, unrestricted volume of Motor Oil available for the suction performed by the Gerotor Oil Pump... so very far away from the Oil Sump.

This On Topic Link will address all aspects of this problem...with the topic of increasing the size of the Oil Pick Up Tube Screen portion to assist in allowing the Gerotor an easier time of trying to get the Oil out of the Modified Sump...and up into the Innards of the Engine. Many technical issues are covered in this article that might explain the Connecting Rod Bearing Failure at the very back portion of the Engine due to Partial Oil Cavitation leaving those Bearings naked when Bubbles formed during periods of the displaced Engine Oil not being able to travel back into the Sump fast enough to replenish the Gerotor Pump. Also.. Due to its largely lateral position of the Oil Piping... this would invite the presence of any Air being sucked in with Motor Oil to float to the surface of the Oil traveling back to the Gerotor after bubbling up to the upper inside area of that Long Tube:

http://www.enginebuildermag.com/2009/06/oil-pump-technology/

...and this is a Link to @limequat 's original work with photos showing the modified design:

https://forums.trailvoy.com/showthread.php?t=51636&page=1

And to answer the Question of "At What Height should the Oil Pump Pick-Up Screen be Set At for Proper Performance?".... Here is George Richmond from Melling describing the typical Oil Pick-Up Screen set up in V-8 Engines that may be worth following if a GM V-8 Oil Pick Up Screen and Tubing are chosen for this adaptation down inside the Modified Oil Pan of an LL8 Engine:


By now,,, some of us are asking the Question... "So What Bobby... Big Deal... How much Harm can Bubbles be with so much Oil getting Pumped through the Engine Block and into and around the Bearings?" The answer is dramatically emphasized in this demonstration of whether or not The presence of Gas Bubbles in a Liquid Medium will Reduce the Hydraulic Pressure nearby enough to say... Sink an Ocean Going Vessel. The important issue to recognize here is that Reliable Engine Oiling is singularly dependent upon this One Principle:

"All Liquids Are In-compressible..."

This matters a Great Deal because if Air Bubbles get Mixed in with In-compressible Motor Oil... it is the BUBBLES that will compress and reduce the Volume of Oil present in between the Bearings and the Outer Crankshaft Journals... and when THIS phenomena occurs... The Bearings are exposed to Metal on Metal contact and very soon afterwards will Over Heat, Expand and seize to the Outer Crankshaft Journals... spinning inside of the Aluminum Block and ruining the Motor. If you don't think these principles are Universal when it comes to the Physics involved... just watch what can happen:

Thank you for the info. The screen opening/flow restriction is of particular interest.
Does anyone know if 24" to 25" height from bottom of oil pan (modified) to top of cam cover at timing gears is attainable with a 4.2 Vortec?
 

cornchip

Member
Jan 6, 2013
637
I ended up with exactly 25 inches on my pan. Might be a little bit more room if you get closer to the pickup up front.

y4m5KwXQ5YZb_tTUmdiRk83xd-KvGlEPV3JfTiVUpLQX05cp23dgGoi6F88Og2FFpR77_h6qusJ6E8_-4y2VT23K7QslThfhAILqmlg6vvGDMk76pHd2XsZ3lqSOQpMGmmQxkFGCgpni7meGhXtOHzQHEqhfUKq0aoiQFFtt6ax_REvOvtZDThUB4Vlr3ZQB0aLj0toJvFftrFzpdlSd1j6sg
 
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damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
I ended up with exactly 25 inches on my pan. Might be a little bit more room if you get closer to the pickup up front.

y4m5KwXQ5YZb_tTUmdiRk83xd-KvGlEPV3JfTiVUpLQX05cp23dgGoi6F88Og2FFpR77_h6qusJ6E8_-4y2VT23K7QslThfhAILqmlg6vvGDMk76pHd2XsZ3lqSOQpMGmmQxkFGCgpni7meGhXtOHzQHEqhfUKq0aoiQFFtt6ax_REvOvtZDThUB4Vlr3ZQB0aLj0toJvFftrFzpdlSd1j6sg
Very good, Thank you! That gets me into the realm of "this will probably work" in a Z car. We are planning on a fabricated front crossmember as part of the build up anyway. We can gain an inch or so there and I don't mind raising the stock hood bulge about an inch. After talking to my tuner guys, an '08 or '09 is their recommendation as far as engine management versatility...thoughts? Was told- '06 and '07 are year specific ECM's and the newer stuff would lend itself to more tuning options if power adder is in the future.
Do you have a side view of your engine with pan?
 

damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
Looks like I need to visit the junk yard and look at the intake. Highest part of engine should be the cam cover for my project. Is the intake aluminum or plastic?
I imagine I'll build an intake similar to this so the cam cover is highest point. Thanks for all your responses. Will keep this going as things progress.
ccrp-1108-hp-turbocharged-vortec-inline-six.jpg
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
The stock intake is a composite plastic. If the valve cover is to be your highest point, you're looking at a lot of custom fabbing for the intake, like the one in that pic.

You are correct, and @limequat can confirm, the '08/'09's have more tuneability and are overall a better engine but may be a little harder to find than the older ones, as well as more expensive.
 
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limequat

Member
Dec 8, 2011
520
MY08 09 are highly recommended for more versatile engine control. Boost has been done on 06 and 07 many times, but you lose some capability to the newer PCMs. 02-05 PCMs are not receptive to boost, but are OK for swaps where further modifications are not planned.
 

limequat

Member
Dec 8, 2011
520
It's also worth noting that the cam cover changed from plastic to aluminum for MY2006. It also got fractionally smaller, as the VVT actuator changed technology.
For the supra, my two worst points for hood clearance were the oil fill on the cam cover and the throttle actuator.
 

damifino

Original poster
Member
Oct 28, 2018
11
North Carolina
It's also worth noting that the cam cover changed from plastic to aluminum for MY2006. It also got fractionally smaller, as the VVT actuator changed technology.
For the supra, my two worst points for hood clearance were the oil fill on the cam cover and the throttle actuator.
All you guys' input has been helpful. As long as it fits under the hood with a modified pan and/or crossmember (less intake) this will be a go. Fabricator's motto: "Where there's metal there is hope.".....and I have plenty of metal.
 

mrrsm

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Oct 22, 2015
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You might want to send a PM to another of our well-known GMTN Members… “The Bruhaba” @bruhaba and consult with him about how he fabbed up his Intake Manifold for his Eaton Supercharged LL8. Perhaps he will share that data … or point you towards someone who has the plans already drawn up for something more "in-line" with what you need. The one often overlooked consideration when fiddling around with fabricating Intake Manifolds has to do with the Length of the Runners.

Even this (6) Cylinder Engine requires that the In-coming Air must achieve a certain Velocity to maintain VE (Volumetric Efficiency) and if you simply make what amounts to an Aluminum Rectangle that lowers the Intake Manifold Profile... if your engine remains Naturally Aspirated and unassisted by either Turbo or Supercharging.... its performance could suffer (along with exhibiting bizarre harmonic vibrations) if those Semi-Circular Runner Lengths are simply done away with. This video shows his unique Supercharged 4.2L Trailblazer:

 
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