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Mandatory oil system mods

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JolleyGreenSST View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JolleyGreenSST Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 2:20am
Originally posted by 69 ambassador 390 69 ambassador 390 wrote:

Originally posted by Trader Trader wrote:

The extra quart was a thought up patch early on as people thought the problem with the AMC motor was too much oil being pumped to the top of the cylinder heads and that caused the oil pick-up to catch air.
Modern thinking and track proven is oil aeration being the big problem, oil frothing in the crankcase and picking up air. The extra quart would actually aerate the oil more as the crankshaft spins through the excess oil.
This air/oil mix would then be pumped through the engine and not lubricate near as well as straight oil. Air separation in the top of the engine can cause even more problems if not achieved in the valley or rockers.
An extra quart oil pan reduces aeration of the oil and also provides for "spirited" driving as oil is pushed front to back or side to side.
The stock pan with stock oil level is good for every day driving. 
 
Um, Not!    The extra quart is still below the baffle in the stock pan.  The oil level is far below the baffle in a running engine and at no time is the crankshaft spinning in the sump oil.  A full quart or more is trapped in each cylinder head and another in the lifter galley during higher speeds.  This leaves only two in the pan.  I have run many engines on my start stand and sometimes use slotted valve covers during valve adjustments on running engines.  The oil level during 2000 rpm cam break in is usually an inch or so in the heads and much more at higher speeds.  I have NEVER witnessed any foamed oil in the heads of a running engine.  But this is with just limited AMC experience.  I've only built about a hundred!
 
Sounds right to me and I trust hands on experience over theory any day. So my question is would you think its better to run a higher capacity pan or is it fine to just run six quarts of oil in the stock pan?
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wheelz View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wheelz Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 6:05am
Originally posted by 73hornut 73hornut wrote:

Originally posted by wheelz wheelz wrote:

I have also used this to adjust oil pressure if there is too much after a new build before starting


ADJ OIL PRESSURE REGULATOR
Anyone sell this in a kit form?


T/A performance. Its a Buick part and the bolt is a different size so I transfer the adjuster to an AMC bolt by drilling the same size hole and using an AMC spring
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farna View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 6:11am
Trader has a few things correct -- aeration/frothing of the oil is bad, the extra quart allows more "spirited" driving, and the stock pan with stock oil level is good for everyday driving.

69 ambassador 390 has the reasons the extra quart works correct, and is also correct that even on startup with all oil drained in the pan six quarts won't contact the crank, at least with the car near level. I suppose it might if on much of an incline, but even then only for a second or two until the pump sucks it up into the engine -- by the time the engine fires it's sucked up half the oil.

For regular racing a high capacity pan may make sense. For the occasional trip down the strip or autocrossing the extra quart has proven to be more than adequate. I'd only invest in a high capacity pan with a "floating" pickup only on a high dollar race engine (or any high dollar build). Well, $5K is "high dollar" to me, but what I mean is those $10K+ engine builds. $5K gets you what, a mild but well built engine -- at least if you have a good shop build it. Plenty people on here could build a healthy street/strip engine for $5K or less. Really depends on what you start with and just how "healthy" you want it. And how good/licky at parts scrounging you are. I think I could build one (assuming I started with an engine in decent condition) with all new parts for $5K easy enough.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73hornut Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 7:59am
Originally posted by wheelz wheelz wrote:

Originally posted by 73hornut 73hornut wrote:

Originally posted by wheelz wheelz wrote:

I have also used this to adjust oil pressure if there is too much after a new build before starting


ADJ OIL PRESSURE REGULATOR
Anyone sell this in a kit form?


T/A performance. Its a Buick part and the bolt is a different size so I transfer the adjuster to an AMC bolt by drilling the same size hole and using an AMC spring
Is there a link to the parts used? Thanks

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Red Devil View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red Devil Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 8:49am
Originally posted by farna farna wrote:

69 ambassador 390 has the reasons the extra quart works correct, and is also correct that even on startup with all oil drained in the pan six quarts won't contact the crank, at least with the car near level. I suppose it might if on much of an incline, but even then only for a second or two until the pump sucks it up into the engine -- by the time the engine fires it's sucked up half the oil.
 
... if the engine has sucked up half the oil shortly after it's fired, not surprising we have never ending oiling issue threads :)
 
Also, remember that the engine is angled down approx. 3 degrees in the chassis, so when doing the "extra quart" test, make sure the pan is at a 3 degree down angle to simulate start up.  Then if half the oil is sucked out of the pan shortly after start up, lower the level by half then angle the pan 30 - 45 degrees forward, rearward and side-to-side to simulate braking / acceleration / cornering oil levels (45 degrees being 1-g load) ... and check if the pickup is generously submerged in oil under all conditions. 
 
Then consider your application and whether the stock pan with 5 quarts or 6 quarts is enough. 
 
Hope this helps, RD.
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Trader View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 9:11am
Just a little light reading:
I find figure 1-5 and connecting rod lubrication interesting as it seems to me a plausible cause for #6 failures and typical AMC failures towards the rear due to "bubbles forming and blocking oil flow.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shawn_Watson Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 9:25am
You're definitely going to have aeration issues if the "fix" for poor drainback is more oil, at least in my opinion.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 10:00am
Typically on most engines, 1 to 2 quarts of oil are in motion above the oil pan. Adding one quart would likely be fine if on an AMC this still keeps the crankshaft from aggressively aerating the oil.
As RD pointed out the aggressive driving is another matter.

On deceleration the "police pan", you would think, without the "standard pan" baffle, move so much oil to the front of the engine that you would aerated heavily but also expose the oil pickup to air.

I'm not convinced the "police pan" is a desirable thing to have.

Just reading on the g forces, a stock 1970 Go Pack AMC by the numbers (time/distance) would pull 0.4g on acceleration and with disk brakes was best in class and pull 0.6g braking.

Not bad for a 1970 vehicle, as a BMW M3 today is best in class pulling 1g (32 ft/s-sq) braking.   


Edited by Trader - Feb/08/2019 at 11:02am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 10:58am
Originally posted by Trader Trader wrote:

Typically on most engines, 1 to 2 quarts of oil are in motion above the oil pan. Adding one quart would likely be fine if on an AMC this still keeps the crankshaft from aggressively aerating the oil.
As RD pointed out the aggressive driving is another matter.

On deceleration the "police pan", you would think, without the "standard pan" baffle, move so much oil to the front of the engine that you would aerated heavily but also expose the oil pickup to air.

I'm not convinced the "police pan" is a desirable thing to have.  
I have had one on my AMX for 25 years with zero problems.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wheelz Quote  Post ReplyReply Direct Link To This Post Posted: Feb/08/2019 at 12:00pm
Adding a remote oil filter will also add capacity to the system. I like to run the Bulltear adapter and braided lines to the filter adapter. Along with my 8 qt Milodon I have almost 10 quarts but I only put in 9 so I have 7 in the pan
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