Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - Debating oil mods for a 401
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Debating oil mods for a 401

 Post Reply Post Reply Page  <1 345
 Rating: Topic Rating: 1 Votes, Average 5.00  Topic Search Topic Search  Topic Options Topic Options
Boris Badanov View Drop Down
AMC Addicted
AMC Addicted

Joined: Dec/14/2013
Location: NH USA
Status: Offline
Points: 3933
Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Nov/08/2017 at 4:07pm
I have two engines with the lovely little plastic button in place.

Both are Nash Cans... (AMC)

They will not go together without them being replaced by brazed in steel.
Gremlin Dreams
Back to Top
ruphianh View Drop Down
AMC Apprentice
AMC Apprentice

Joined: Jan/21/2018
Location: CA
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote ruphianh Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 9:35am
Originally posted by SKeown SKeown wrote:


 I never switched to a different filter, but it's probably not a bad idea. When Hurst corp. converted 50 AMX's for S/S competition it wasn't long before it was realized that an additional 2" depth to the oil pan was needed to prevent oil starvation and blown engines. I've seen the Western Union first hand that called for that sent to AMC dealers.

 In an attempt to see more than 45 PSI hot pressure with 20/50 racing oil I tried everything including bushing lifter bores and saw no difference at all. That was until I fitted an adjustable pressure bypass spring, once I did that 70 PSI or more was no problem. I had tried different relief springs early in the process with no change either.

 Remember, I tried everything possible to enhance my engines oil pressure without any change until the increase in bypass pressure proved that much I had done was unnecessary.


I have a builder building a 401, I’d like to send him this screenshot. For my own education, what is an adjustable pressure bypass spring?
Back to Top
Red Devil View Drop Down
AMC Addicted
AMC Addicted

Joined: Jul/10/2007
Location: Canada
Status: Offline
Points: 1671
Post Options Post Options   Thanks (0) Thanks(0)   Quote Red Devil Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 10:53am
The relief valve is the spool & spring under the hex-head cap on the filter housing. Stock is a fixed setting, since the spring is not adjustable. The relief is the primary control of oil pressure at higher rpms (pump flow vs. clearances limits lower rpm pressure) ... assuming decent clearances and correct oil viscosity.

Most are fine with the fixed spring. Some shim it. Some make it adjustable with various means - e.g. thread the spring retainer and use a bolt with sealant and jam nut or a sealing nut. Some fit a different spring. Some run tight clearances to dump more oil over the relief effectively displacing the spool further raising system pressure.

Mine is like this:

No kits available that I'm aware of, so simplest to run the stock setup and adjust only if you feel the need. Stock works for most with stock clearances.

Hope this helps, RD.
Back to Top
JERSEYJOE View Drop Down
AMC Addicted
AMC Addicted

Joined: Oct/23/2008
Location: TUG HILL NY
Status: Offline
Points: 1454
Post Options Post Options   Thanks (0) Thanks(0)   Quote JERSEYJOE Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 11:03am
1985 J-20 PLOW TRUCK
1977 CJ 7 360 T-18 D 300
1970 AMX ex-SCCA car

Back to Top
73hornut View Drop Down
AMC Addicted
AMC Addicted

Joined: Jul/03/2007
Location: Southern Oregon
Status: Offline
Points: 2907
Post Options Post Options   Thanks (0) Thanks(0)   Quote 73hornut Quote  Post ReplyReply Direct Link To This Post Posted: Jun/14/2019 at 9:49pm
My new oil modification.
5W30 Renewable Lubricants, Super High Performance Passenger Vehicle, Bio-SynXtra, motor oil = 130,436 psi
This patented biobased motor oil uses agricultural vegetable oil base stock, and is biodegradable. It claims to provide optimum performance in newer High Output Turbocharged and Supercharged “GASOLINE” engines. It also claims to have been formulated with the latest additive package components added to that base stock. It has no Motor Oil Industry certifications, but claims the formula passed the tests required for API SN. And it claims superior wear protection and high temperature stability, both of which proved to be true in my Engineering tests. In addition, it also claims to have a very high Viscosity Index value, which helps against fuel dilution concerns. The higher the Viscosity Index value, the less the oil’s viscosity is reduced as it heats up.
zinc = TBD
phos = TBD
moly = TBD
This oil was tested Summer 2018.

The psi value of this oil, which came from testing it at the normal operating test temperature of 230*F, put it in the FANTASTIC Wear Protection Category.

I also went on to test this oil at the much higher temperature of 275*F. At that elevated temperature, any hotter and thinner oil is expected to experience a drop in Wear Protection Capability. This oil had only an extremely small 0.7% drop in capability. Even at that elevated temperature, it produced 129,486 psi, which still kept this much hotter oil in the FANTASTIC Wear Protection Category.

I also tested this oil for its onset of thermal breakdown point, which was 275*F.

This was the first biobased motor oil I ever tested. And its performance was EXTREMELY IMPRESSIVE. These results probably surprise a lot of people, since this oil wasn’t even made from petroleum base stock. So it appears, there could be a very bright future for biobased motor oil, if they are formulated well.

And the test data produced by this biobased oil, further backs up what I have said about a motor oil’s “base stock” NOT being all that critical, it is the “additive package” that IS critical.

Edited by 73hornut - Jun/14/2019 at 9:52pm
71 Javelin
74 Gremlin
79 Spirit AMX
Rogue Valley Rumblers
Like Us on FB
Back to Top
billd View Drop Down
Moderator Group
Moderator Group

Forum Administrator

Joined: Jun/27/2007
Location: Iowa
Status: Offline
Points: 30497
Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/14/2019 at 10:07pm
And 5w-30 is a proven good "viscosity" to use. 
Even at 275 degrees - which is pretty hot for oil - it performed far far better than what most folks use and call "good oil".
Impressive........... hmmmmmm

update - looked up some reviews - and lab testing supports the "less wear" testing.
This oil provided better wear readings in my track car (based on used oil analysis), and longer useful service life than any of the commonly available synthetics (and I've tried most of the others).

Edited by billd - Jun/14/2019 at 10:12pm
Back to Top
 Post Reply Post Reply Page  <1 345
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.093 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
If you have problems logging in or registering, then please contact a Moderator or