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AMX 401 Take 4 |
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Boris Badanov 
AMC Addicted 
Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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 Posted: Apr/19/2014 at 4:14pm |
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Indeed you do.
I measured my block off of Centerline of Rotation and got a deck height of 9.218 from the centerline of the main way. It's odd that there is a disagreement about the factory deck height. But this block is definately 9.218 After years of building the infidel Chevrolets I was amazed at how perfect the main line and cam line are in relationship to the decks. AMC obviously cared when they machined these 401 blocks. It's nearly perfect. Did AMC make a deck height change in the 1970's ???? The deck height will change by a couple of thousandths when I clean it up. The calculated height I am currently using to order rods and pistons is 9.215 to allow for a light dust cut on the top. I prefer a tight quench, .035 to .040 max. this makes for excellent responce at low speeds and tends to help with detonation. Edited by Boris Badanov - Apr/19/2014 at 4:18pm |
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Gremlin Dreams
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Javelin69
AMC Apprentice 
Joined: Dec/11/2013 Location: Madison wi Status: Offline Points: 187 |
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Posted: Apr/20/2014 at 3:27pm |
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What kind of timing cover is that with the machining in the oil pump?
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Rebel Machine
AMC Addicted
Joined: Jul/03/2007 Location: Western Il Status: Offline Points: 5122 |
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Posted: Apr/20/2014 at 7:02pm |
Original AMC cover with some modifications. -Steve- |
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Rebel Machine
AMC Addicted
Joined: Jul/03/2007 Location: Western Il Status: Offline Points: 5122 |
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Posted: Apr/26/2014 at 11:25am |
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Got the engine & trans in the car and running last night. Took it for a road test today. No improvement. Oil pressure still low. Under hard acceleration it empties the pan and the pressure drops to zero.
I give up. Words can't express my disappointment or anger. After two years and tons of cash (five figures) I'm done. It can rot where it sits for all I care. No more. -Steve- |
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304-dude
AMC Addicted
Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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Posted: Apr/26/2014 at 12:08pm |
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Wow!!!! I can see your anger, and understand your disappointment. If we only had what Traco setup for Penski. Then we'd know what is really happening with the internal lubrication flow and such.
With modern electronics, and someone willing... some high intensity LED lighting and a few window ports or USB web cam placed in a strategic location... engine must be cold, else it will melt. It may be worth a try just to get a view of what is happening, after all you dumped good money, might as well make a peep show out of it. Just my 2 cents... If I had money I would gladly adopt Damien from you. |
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348AMX
AMC Addicted
Joined: Jul/03/2007 Location: Massachusetts Status: Offline Points: 4165 |
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Posted: Apr/26/2014 at 12:25pm |
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I can't believe that there is no improvement on a completely rebuilt "blueprinted" engine over your previous set up???? There HAS to be a component related to oil circulation that is was re-used on this rebuild that would be the "smoking gun".....maybe try getting rid of that oil line the valley(even if your positive it isnt the cause) and swapping to a known properly working factory stock timming cover.
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304-dude
AMC Addicted
Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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Posted: Apr/26/2014 at 1:08pm |
Good points! I have the option for an oil bypass on my block... I removed the fittings, to have it welded closed. Many like it, but I prefer adding oil galleries on engine end of mains 4 and 3. This Equalizes pressure at the rear. Though you will need to find a short oil gallery plug to ease restriction at the back gallery feed from main 4. |
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Rebel Machine
AMC Addicted
Joined: Jul/03/2007 Location: Western Il Status: Offline Points: 5122 |
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Posted: Apr/26/2014 at 1:18pm |
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Since I'm a glutton for punishment I've been trying to narrow down the constants in this whole saga.
The only two constants I can think of are the engine builder and myself. I don't believe it's either of us (he's got 30+ years of performance engine building including doing engines for NASCAR Nationwide cars). This being the case there could be a parts issue. I got thinking perhaps we've had a rash of faulty bearings so I went through my receipts. Here's what's listed. Back in 2001, when I had the first 401 built (held together for 8 years), the bearings were: Rod - CB8109P .010 Main - MS 1041P .010 Cam - SH671S In 2005 I had the '70 390 in my old AMX done. Engine had no oil pressure issues. Bearings were: Rod - CB819 .020 Main - MS1041 .010 Cam - SH671S In 2011 I had the first 401 rebuilt. This is when the oil pressure issues started. Bearings were: Rod - No Part Number Listed Main - MS1041P-020 Cam - N-9 In 2013 I had this latest 401 built (my current pain) Bearings were: Rod - CB-819P-10 Main - MS-1014P-10 Cam - N-9 I'm going to drop by the machine shop Monday and discuss this with the builder and see if he's used these N-9 cam bearings in anything else. -Steve- |
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Boris Badanov
AMC Addicted
Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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Posted: Apr/26/2014 at 1:26pm |
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AMC engines tend to pump the oil up to the top end and leave the oil pan empty.
I have weathered the wrath of others here by calling the AMC / Buick oil sistem the worst in a modern V8. Buick is VERY similar and suffers some of the same issues. The problems that some here seem to suffer is caused by over oiling the top end while it can not return to the pan fast enough. You make mods to deliver more oil and it gets worse. I have been there. There are solutions. Some are not easy and all that I know save one require the heads to come off. On a 1970 390 I made a hole in the valve covers above the rear exhaust port connecting them to the pan on the drivers side. They both MUST feed the DRIVERS side in a downward direction so the crank windage does not pump the oil back up. This mod solved my problem. It is better if you machine the rear of the heads to get lower into the valve seat area but since you may have over a quart of oil in each head this is a help. Carefully de-burring all oil return holes also can help. But the AMC design has a laundry list of flaws. All are pretty easily bandaided or even fixed. Oil return flow is my pet peave with AMC, an otherwise masterful example of mechanical engineering crippled by the oiling system. Return is the biggest nightmare (after that nasty little plastic button on the oil pickup). #1, Oil stacks up in the timing case. My fix was to dummy it up and be sure the front main and gasket/seal are not impeading the flow, or as little as possible, careful radiusing of non critical surfaces may have helped. #2, Oil stacks up in the valve covers. Disintegrating umbrella seals make it worse. My fix is described above. #3, Oil from the top end is dumped in the rear of the lifter gallery right on top of the crank. See #2, most of that oil comes from the lifters pumping it to the valves. While working in the aftermarket Harley Davidson business i discovered that all lifters are NOT created equal. While we have never had a reliability issue with any brand there is a HUGE difference in the amount of oil pumped to the valve train. In the case of a stock HD Twin Cam motor the stock Delphi GM lifters are unbeatable. S&S worked well also. Some other well known names pumped so much oil to the top that it caused major oil return issues in the HD motors. So big that rocker covers leaked profusely. Sometimes when I hear these oil related stories I sense you really have a lifter problem. What most people, even you major gear heads, do not know is that lifter pump up has nothing to do with oil pressure. As long as there is enough pressure and volume to deliver the oil to the lifter the lifter makes it's own pressure in the tens of thousands of PSI at times. If the metering in the disk is designed for high bypass, like in a Rhodes lifter, you may pump a scary amount of oil to the valve covers. Food for thought. Disclaimer here. I am offering only ideas, if you aint 10000000% sure of what you are doing NEVER cut or modify ANYTHING. Edited by Boris Badanov - Apr/26/2014 at 1:33pm |
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Gremlin Dreams
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addic
AMC Nut
Joined: May/01/2008 Location: Kansas City Status: Offline Points: 370 |
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Posted: Apr/26/2014 at 3:59pm |
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I also was like you ready to give up on amc engines,last final engine I smoothed out the inside of block for better oil return, and tossed the timing cover for a indy cover and oil pump, and was going to suggest you do the same on your other post but didnt, because of cost ,,,but I think its well worth it!
The Indy cover has been great,cons $1000  lifters leak,I bet it takes care of that,,, If you run your amc engine hard you need the indy,and for a regular build use amc cover, just my 2 cents
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73 401 Pierre Cardin X P1
73 401 Pierre Cardin X F3 70 X 390 4spd 69 X 401 6 spd 69 AMX 401 auto BSO 73 AMX 401 4speed pc 73 vette 427sb 5spd 73 vette convt.? 08 zx14 |
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Javelin69 wrote: