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Fresh 401, Quest for Oil pressure
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rang-a-stang View Drop Down
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Points: 272 		Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Oct/13/2020 at 5:33pm
Today I pulled the timing cover and tried to remove the timing chain. I cannot get the the lower sprocket to budge. I tired pry bars, I tried a 2 arm puller, and it won't move. I got frustrated and flipped the engine over and started my bottom end inspection. Pulled the pan and this is what I saw:

A quick look around and everything looked clean. Inspected the oil pain and found no sludge, no shavings, nothing shiney, nothing gritty, just clean oil pan.

I took a close look at the pickup. Nothing in the screen other than what looked like a piece of tissue paper. No idea where that came from. 

Then it got real. My mains are severely damaged. Whatever got to through my oil pump got to my mains. 





The crank did not have any grooves that I could feel so it may just be OK but since I need my clearances corrected anyway, I didn't even measure. My crank needs to be machined. 
I then moved on to the rods. I wasn't in the mood to do all the rods knowing the crank needs servicing any way so I just inspected #1 and #7. They looked the same. They look like this:


Not totally garbage but, again, the engine needs machine work so they are going to end up in the trash too. 
While I was down there I spent some time trying to verify my ARP nuts are totally seated. They seem to be. It looks like when the machinist blueprinted the rods last time he flattened the rod flanges. If you look at the bottom of the nuts, you can see witness marks that is was seated flatly on the flange:


So tomorrow I start looking for a machine shop. I will have them get that timing sprocket off so we can inspect the cam and it's bearings. Should I drill out the oil feel line that goes up from the oil pressue sensor port up to the lifter valley? I saw them do that Hot Rod Garage. I will have the block tanked and my crank serviced to the correct clearances. I feel pretty defeated and I am scared for my life when my wife finds out how much this is going to cost. 
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I dont see anything to freak out about. It was assembled dirty. polish everything and re-assemble with new bearings
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Originally posted by Hurst390 Hurst390 wrote:

I dont see anything to freak out about. It was assembled dirty. polish everything and re-assemble with new bearings
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Points: 3130 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 73hornut Quote  Post ReplyReply Direct Link To This Post Posted: Oct/13/2020 at 7:13pm
2 things I will tell you from experience, either the oil passages were never cleaned after hot tanking, or, there was debre in the oil pickup that was never removed, more likely passages not properly cleaned.
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Anything in or in the engine get cleaned in a blast cabinet
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Points: 93 		Post Options Post Options   Thanks (0) Thanks(0)   Quote gmonde Quote  Post ReplyReply Direct Link To This Post Posted: Oct/13/2020 at 9:05pm
after going through the post,,if this where my engine,, check crank for any groves from debris, measure the crank to see what you have ,get a new set of bearings rods and mains 
more importantly is the oil pump as mentioned,mesure the pump shaft endplay with the gasket installed and torqued .0015-002 end play is how i set my stocker set up and has 30-40 at idle warm
also block off the bypass for the filter this will make sure oil is going thru the filter 

last point is when the engine is shut down for a period of time  the oil will syphon from the filter back to the pan,, this is a problem when the engine is started and has to refill the filter and prime the system ,no oil pressure for that period of time will take its toll on the bearings as well along with a loose pump clearance 
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rang-a-stang View Drop Down
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Points: 272 		Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Oct/14/2020 at 10:09am
Originally posted by Hurst390 Hurst390 wrote:

I dont see anything to freak out about. It was assembled dirty. polish everything and re-assemble with new bearings
Originally posted by purple72Gremlin purple72Gremlin wrote:

x2
Wow! You guys are making me feel a little more hopeful! I saw copper on my bearings and kind of lost it.
Originally posted by 73hornut 73hornut wrote:

2 things I will tell you from experience, either the oil passages were never cleaned after hot tanking, or, there was debre in the oil pickup that was never removed, more likely passages not properly cleaned.
Yeah, you are probably right. I blew it off when I get it home and I used brake cleaner on it before I painted it but I probably did not spend enough time cleaning it out. 
Originally posted by jblue1555 jblue1555 wrote:

Anything in or in the engine get cleaned in a blast cabinet
Yeah, a few things. Off the top of my head: Oil pan, valve covers, intake manifold, and original timing cover (this is the second one). That very well could be the source of my debris. Newb/rookie move I guess. 
Originally posted by gmonde gmonde wrote:

after going through the post,,if this where my engine,, check crank for any groves from debris, measure the crank to see what you have ,get a new set of bearings rods and mains 
more importantly is the oil pump as mentioned,mesure the pump shaft endplay with the gasket installed and torqued .0015-002 end play is how i set my stocker set up and has 30-40 at idle warm
also block off the bypass for the filter this will make sure oil is going thru the filter 

last point is when the engine is shut down for a period of time  the oil will syphon from the filter back to the pan,, this is a problem when the engine is started and has to refill the filter and prime the system ,no oil pressure for that period of time will take its toll on the bearings as well along with a loose pump clearance 
Understood. I think that is the way I am going. I appreciate the input. 
**************************************
I plan to pull my heads today and set them aside. I will pull all my pistons out so I can clean/inspect the bores, remove the crank and clean it all off and inspect all the journals for gouges and make sure my oil passages do not still have crap in them. I plan to call a couple machine shops to see about getting the crank ground and getting the block tanked again. I spent a good hour and half last night trying to find a set of .001 undersized main bearings and I could not even find an old part number. I really would like to tighten my mains up, at least. They were at .0023 plus or minus .0003 so one of them was at least .0026. My rods were at .0025 so I think I can possibly run the Pontiac bearings Trader recommended here:
http://theamcforum.com/forum/401-rod-bearing-alternative_topic99248.html
My engine is only slightly warmed over and is a daily driver. This is the first engine I have ever really "rebuilt" an engine other than an air cooled VW engine in the 90's so I am sure I made mistakes and miscalculations. This also means I do not get offended when people see things that were probably caused by my inexperience so feel free to call my out for anything you see. I did not tell the machinist what clearances I wanted (mostly because I assumed he would know better than I would). Obviously I did not clean my parts well enough. I am hopeful I can get this back on the road fairly quickly though... 
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rang-a-stang View Drop Down
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OK, I think I am mostly done with inspection. Today all I really did was pull the heads and inspect the bores. Nothing shocking and no deep gouges. 
Even side:

Odd side:

I looked into my coolant passages and there is MORE CASTING SAND in there!! My goodness! I poked a good 2 cups out last time! There is another, about 3/4" deep pocket of sand in the back around #7 and #8! I am not sure if you can see it in this picture but I tried. The big shiny piece is a flake of rust. It looks shiny because it is wet and my flashlight is aimed straight at it:

Then I called a couple local machine shops and a not so local but kinda local shop: Valley Head Service. Larry at VHS said he can straighten me out, machine wise, and set up my short block in about a week. They are not cheap but I would rather spend the money now and not have to deal with this later. He has an amazing reputation out here in SoCal. Plus he said a sentence that pretty much had me "That motor is the ugliest thing around but man, don't mess with them! They have surprised so many big 3 drivers! They have so much power potential!". He "gets" it. All the other shops acted like I was bringing in a briggs and stratton crank.  
Normally I would love to be the one to put my engine back together but look how that worked out last time. Dead
So my plan is to finish taking everything off the block so it is down to rotating assembly minus the cam, then bring the whole thing down on Saturday morning for him to inspect and give me an accurate quote. While it is at his shop I will clean my garage, clean my tools, clean my heads up, clean my garage, get ready to slam the long block together, clean my tools, and clean my garage.


Edited by rang-a-stang - Oct/15/2020 at 10:55am
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rang-a-stang, Your heads are in very good hands at Valley Head Service, Northridge, Ca. A former employee of their's named Jesus ~three years ago rebuilt my 73 401 Cherokee heads. Jesus really knows AMC heads.  He showed me a album with several impressive dyno sheets on AMC engines the shop had built.  Hot Rodding magazine did a four page article on VHS decades ago stating VHS is the best head shop on the planet. Jesus said he was the foreman of the shop then. There is a photo of Jesus machining a head. 
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Points: 2568 		Post Options Post Options   Thanks (0) Thanks(0)   Quote turbo Quote  Post ReplyReply Direct Link To This Post Posted: Oct/14/2020 at 7:09pm
Well there you go......second time will be the charm.....Stuff happens sometimes
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