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Engine Oil Issue |
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10secterror
AMC Fan Joined: Mar/30/2014 Location: Melfort, Sask Status: Offline Points: 19 |
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Posted: May/17/2014 at 4:13am |
Scratching my head on this problem.
It's a 71 401 AMX Javelin that has not been driven since 1988. I replaced the carb, played with the timing and it ran perfect. No noises at all, and oil pressure was 100 pounds cold. Stepped on the throttle and all of a sudden oil EVERYWHERE in one second! Covered the engine bay, fenders and windshield, cleaned and traced back to a split oil filter. Cleaned up, added oil and replaced the oil filter. Guess what it did again! Split a brand new oil filter. Will drop the pan and replace the oil pump, assuming the it must be the bypass??? Anyone else seen an issue with too much oil pressure doing this? Thanks. |
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rocklandrambler
AMC Addicted Joined: Feb/09/2013 Location: Nanuet, NY Status: Offline Points: 3953 |
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No AMC ever ran 100psi oil pressure cold, let alone hot. If I'm not mistaken the oil pump is EXTERNAL on your engine. No need to drop the pan. Who knows what could have happened to that engine in the last 26 years? You could have 5 generations of mice living in there, and I hope you started the engine on a separate source of fresh clean gas and not anything that might have still been left in the tank.
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Past AMC's
1974 Hornet X (new) 1975 Gremlin X (new) 1964 Classic 660 Cross Country 1965 American 440-H |
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401MATCOUPE
AMC Addicted Joined: May/20/2010 Location: Salisbury, MD Status: Offline Points: 5367 |
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Oil bypass valve in the oil filter adapter is stuck closed and will not regulate......100 PSI is a lot of stock filter. There are some really high end filters that can with stand like 500 psi (Fram HP Series), I am not a fan of Fram regular filters, and i never opened a HP to see if better. The valve is under a External Hex Plug in the adapter the filter screws onto.....inside there is a spring and plunger. I have seen these plungers frozen in place. If stuck in there, sometimes you can used a straight slot screw driver that has a tapered end to fit inside where the spring sits and spin the plunger and put tension it to remove...worst case...take the adapter off the front cover disassemble.
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Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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since this is an engine issue, I've moved it to the engine/V8 area.
Yes, remove that aluminum hex plug, remove the spring and there's a plunger inside that hole. The plunger is hollow on the outer end and that spring fits inside the hollow. The other end is tapered and when the pressure builds up, it pushes the inner end of the plunger against spring force and opens another passage to relieve the pressure. That's what regulates the pressure. Those get stuck either due to sitting, varnishes or acids built up in the oil over time, or DIRT getting to it. It doesn't take but a piece of something about the size if a hair to make that stick. Be very careful not to scratch the surface of the hole or bore that plunger is in, remove the plunger, clean it up so it shines, and make sure the hole is clean, then put it back. Mine runs 80 psi when it's cold to cool, then drops to about 70 or so once warmed up. That's highway driving, 2500+ RPM. At lower speeds, say in town, etc. it's closer to 25+ when hot at about 800 RPM. If you go over 80 with stock parts, stock filter, IMO you're asking for a leak. |
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Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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Blocked or stuck oil pressure relief bypass valve.
Seen it happen. You may have broken the cover like the one I knew of. He had shimmed it for more pressure, over did it. If you are lucky you only blew out the gasket. If the bypass is stuck you will be replacing it anyway. Note, we are not referring to the oil filter bypass valve here, you can live with one of these little deamons blocked.
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Gremlin Dreams
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69 ambassador 390
Supporter of TheAMCForum Joined: Nov/22/2009 Location: Peoria, AZ Status: Offline Points: 3539 |
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If it's stuck and you already have a mess, just pull the plug and start it for a second or two. Watch out because it'll come out like a shotgun slug on opening day.
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Steve Brown
Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |
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bob401
AMC Nut Joined: Sep/23/2009 Status: Offline Points: 263 |
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i ballooned a Fram once, pegged my oil pressure gauge at 120psi, had 80 psi at start up. This was after a mild over haul I did, I think i just cleaned and rechecked the oil relief stuff and it went away.. Still had 80 psi, the car a week or two later busted a u joint, cracked the transmission, and some how in the process lost all the oil pressure too.
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