Re: [AMC-list] ruined in 60 seconds

[Frank Swygert <farna@xxxxxxx>]

First thing I'd check is the oil pressure relief valve. You still have one in the block, correct? And I just thought of something! Your external oil filter setup is what failed. You're getting full oil pressure there no matter what, so the filter gets whatever the pump puts out. That's the problem -- no pressure relief between pump and filter. That's why the full-flow pump has that extra passage to the oil pan and the pressure relief valve in the oil pump cover. 

Unless you can rig a pressure relief in the line between the pump and filter or get a remote filter base that has a pressure bypass you're going to continue with the same problem. I wouldn't have thought the pump would put out that kind of pressure, but apparently it does. 20 psi at cranking is nothing -- my engine puts out the full amount (70+ psi) at cold idle -- opens the pressure relief obviously. Hot idle is a minimum of 15 psi, idling at 600 rpm. So I don't think there is a bottom end issue such as bearings installed wrong. 

Some things we just don't think about until something goes wrong, then it almost seems obvious! I doubt you hurt the bottom end since it had oil and only lost it for a few seconds with no load. If you'd been driving down the road it would be a different story. You might have taken 1000-2000 miles off the life of the bearings, but unless they were perfectly dry or the engine was under load you should be fine. Pull the pan and look if you're scared, but I'd fix the oil filter system and start it up, listen for sounds, attach a gauge, then rev it up to 1500-2000, listening as it goes up. Even if it starts knocking a little you can still rev it up to 1000-1500 rpm with no problems. Likely will ruin the rod, but shouldn't bother the crank unless the bearing is totally gone. 

--------------------
Date: Fri, 23 Apr 2010 13:04:36 -0700
From: tom jennings <tomj@xxxxxxx>
To: "AMC, Rambler, Nash, Jeep and family" <amc-list@xxxxxxxxxxxx>
Subject: Re: [AMC-list] ruined in 60 seconds
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It appears that the oil pressure went insanely high. I was worried about oil
pressure loss (my plumbing, etc) but I just went out and looked at my oil
gauge -- the pointer is on the wrong side of the stop! Eg. it broke
internally after pegging past maximum.

That would explain why a loop of the oil filter gasket exited it's groove
while installed -- it just plain old got pushed out.

It's small comfort knowing it's not my work that failed (yet anyways).


I should have smelled a rat -- I had 20+ psi cranking. I chalked that up to
a new, tight motor. I think the bearings are assembled wrong or something (I
didn't do that). The machine shop assembled the short block.

--
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://www.amc-mag.com
(free download available!)

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