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Codename Bumblebee: Now With Oil Pressure!


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5 minutes ago, Pete M said:

:doh:  that bites  :( 

Yeah, happened all of a sudden too. Last time I drove it it made halfway decent oil pressure. I fired it up today and had absolutely nothing on the gauge and it sounded terrible. I looked in through the oil cap hole and saw that the rockers were totally dry. Then I unscrewed the oil pressure sender and had absolutely no oil come out, not even a dribble. It's full of oil too.

 

Sudden oil pump failure, maybe? This engine has never sounded particularly healthy. I kind of expected this at some point.

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  • Minuit changed the title to Codename Bumblebee: An Unfunny Knock-Knock Joke
On 1/27/2019 at 12:29 PM, Pete M said:

maybe the pickup tube popped off?  a pump is cheap enough that I'd probably put one in and see what happens. 

Half of me wants to do this and half of me just wants to throw a junkyard engine at it. On one hand, this engine kinda sucks in the first place and always has. It's never sounded good and always has seemed very much down on power, and I'm afraid that running it for any length of time with 0 oil pressure has pushed it over the edge. On the other hand, I don't really feel like doing an engine swap on it either. My 91's oil pan was stuck on so much that I'd almost rather just wing an engine at it than do an oil pump in situ again.

 

Oh, I know! I'll let it sit for a few more months! That'll fix it!

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6 minutes ago, Minuit said:

Oh, I know! I'll let it sit for a few more months! That'll fix it!

 

that's been my plan for years now.  :D  surprisingly enough, my truck only gets worse, not better.  :roflmao:

 

honestly, a new pump wouldn't be a bad idea to put on the replacement engine anyway so...  :dunno:  

 

cork gaskets suck.  been there, done that.  I always suggest the one-piece rubber version. :D  

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  • 2 months later...

Alright, this truck's time has come. Time for it to start occupying space in my mind and wallet, anyway. I've come up with a very cunning and detailed plan that definitely won't be derailed the second I actually start working on it.

 

Here's the plan. A good friend has recently indebted himself to me, so I'll have an extra pair of hands to help with certain things. We've recently resurrected his '91 Chevy 4WD truck with a manual transmission, and he's been rubbing it in my face that he owns a running manual truck and I don't. Time to fix that.

 

Step one is finding out whether it needs an engine NOW, or quite soon. I'll drop the oil pan, see if I find the pickup tube laying in the bottom like I expect to, and maybe pop off a bearing cap or two to satisfy my curiosity. I'll have a new oil pan (I don't expect the original to survive the removal process. The one on my '91 didn't), oil pan gasket, and new oil pump at the ready. In the event I need a new engine, those parts can be reused. I'll be doing the bare minimum of effort to try and get this engine making oil pressure again. If the engine doesn't eat itself, move to step two.

 

If it knocks or still doesn't make oil pressure after step one, I put an engine in it. If that happens, I'll be keeping the Renix injection system and doing the job as quickly and easily as I can. Then skip to step two.

 

Step two is to get it driveable without fear of death. This'll mainly include a complete front end rebuild. I'll slap those nasty out-of-round Cooper tires I still have on it just so it has a matched set of tires. The door striker panel is cracked, so that will need to be welded up. I now own a welder, so I'll be sure to embarrass myself when I post pics of my welding on here. I'm tired of dealing with the stupid Renix cooling system, so it's going bye-bye.

 

Step three is to get it to the point I actually want to drive it. This is the part where I find red doors (I'll add power windows if the doors I find have them), a red hood, and rattle-can the cab red so I actually want to be seen in it. At some point I'll have to address the driver side floor, so we'll put it in step 3. The windshield was cracked when I bought it, and that'll need to be fixed before this thing sees many miles. Also, I'd kinda like a gas gauge that works. Also, a headliner and maroon seats would be nice. I aim for this to be a working truck that I don't have to worry about getting the carpet or seats dirty in, so I'd really like some vinyl seats. The rubber floor mat it has now can stay.

 

I'd really like some A/C in this thing (it's the only vehicle left in the entire fleet that doesn't have working A/C), so I might be doing some exploratory surgery on that to see if the current compressor is usable. I don't have a lot of hope that it will be, since somebody seems to have jumped the clutch to be always-on when A/C is selected, even with the engine off. It's a virgin R-12 system, and I really don't care for my refrigerant eating the ozone layer or costing $30 a can, and R-12 does both. I may throw it all out and do a '96 A/C system swap as I did in my '91, since I've been very happy on the one hot day there's been since I rebuilt the A/C in that truck.

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  • Minuit changed the title to Codename Bumblebee: An Unfunny Knock-Knock Joke?
45 minutes ago, Pete M said:

sounds like a good plan  :D  especially the AC part!

I'm officially ruined. I won't suffer no AC even in a "beater" truck anymore. Fixing AC is one of my favorite things. Totally changes how the vehicle feels.

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  • 3 weeks later...

LIVE UPDATE! As live as it can be, anyway.

Oil pan's off, and here's what I know so far.

- The engine had plenty of oil in it.

- The oil pan came off with absolutely no fuss. 3 hammer blows and it was off, most likely because the oil pan gasket has been changed. It maybe took an hour to get the pan off, including jacking it up.

- There were no chunks of metal in the oil pan, nor was there a pickup screen sitting in the bottom.

- A few of the rod bearings are questionable at best.

- There was no gasket between the oil pump and engine block.

- I found some solid material (RTV? Pieces of gasket? It wasn't metal) in the pickup screen, but it didn't look to me like enough to stop it up.

- The oil pump impellers are not damaged and spin freely. I did get it to pump a little bit of oil by spinning it with a drill.

 

Any thoughts? I'm going to get a bite to eat and go to the post office, and then I'm going to give the pickup screen a closer look. The biggest clue I have so far was the unknown crud in the pickup, but it's still not enough that I would expect the pickup to be completely plugged. Remember, this thing had 0 oil flow at the pressure sender suddenly.

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12 minutes ago, RustyRodder said:

Sounds similar to my engine- Made about 5lbs of oil pressure at best, old pump spun and looked fine.  but was just bad. 

As for the crud, my guess would be RTV.  If the engine has been opened, maybe little bits of extra broke off and just floated around. 

This one made pretty decent oil pressure at cold start, not so great oil pressure once warm... and then one day I went to start it and it had absolutely nothing. I have every reason to believe the pump was in good shape, at least before the sudden loss of pressure.

 

As to RTV getting into the pump, I definitely can believe it. I'm not too sure what it was in there, but let's just say this truck has been worked on by some careless individuals. Lots of hackjobs on this one. Lots of random loose bolts and other stuff. The gasket was cork with blue RTV, and I can definitely imagine a piece breaking off and getting into the pump pickup. There's also some sludge in the old pan right under where the pump sits.

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1 hour ago, RustyRodder said:

How is the screen/pickup tube?

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This is after removing a handful of fingernail sized pieces of junk. All of them were hanging out on the bottom cover of the screen, some of them wedged in the "hump" in it. It didn't look stopped up to me, but who knows?

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I probed the oil pressure sender area, and from what I was able to tell there wasn't any restrictions. Can't rule it out though.

 

I packed the oil pump full of assembly grease and tried the drill priming trick again - the pump shot a column of oil about 2 feet high at me. The pump certainly doesn't seem to lack for eagerness, I'll say that.

 

I've got half a mind to just throw it back together and see if I can get the pump to prime installed on the engine. I'll have to make a gasket though - can't get just the gasket by itself.

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... however, that doesn't rule out the possibility that the oil pump is just worn out enough that the oil could drain out of it over time, causing it to lose prime. I'm not loving the idea of tossing a pump at this questionable engine, but I'm not sure that would be something I'm able to detect.

 

When I noticed the loss of oil pressure, I had not started the engine for a very long time. The more I'm thinking about it, the more this seems like what's happened. Kinda wishing I would've kept the 91's old oil pump about now. That thing had oil pressure immediately after sitting for something like 6 years without starting.

 

Oh screw it, I'll just order a rebuild kit for the pump I've got. I need the gaskets anyway, and it's cheaper than buying a whole pump.

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Woohoo!

 

We have achieved oil pressure once again! I rebuilt the oil pump with a Melling K-81 kit (mostly for the gaskets) and put it together this afternoon. Everything went back together easily and the oil pump primed right up. The new gears in the kit are much tighter than the old ones. That may have been my problem to begin with - upon looking at them closely, the old oil pump gears had a fair bit of slop.

 

The engine doesn't seem to have picked up a rod knock as I'd feared. It sounds more or less the same as I remember it, with a very pronounced top end clack, and it may have taken a slight hit to its oil pressure, but I think we can nurse this engine along a little bit longer.

 

On to STEP TWO!

 

Fun fact - the driver door won't close with the truck on jack stands.

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I renewed the registration on it today and went for a quick drive. It drives exactly like it always has, and the oil pump rebuild has even brought it within the acceptable range for hot oil pressure at about 20psi at idle. The engine runs and sounds no different from before the incident, and I think I might try some of that Marvel Mystery Oil stuff in the oil to maybe try and free up what I'm pretty sure is a very collapsed lifter.

 

Three things that need to be addressed soon - the front end hasn't gotten any better, the brakes are awful, and the cooling system doesn't hold pressure. Other than that, it's mint!

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  • 1 year later...
14 hours ago, 89 MJ said:

Any updates on this?

Actually yes. Since the last update, I have stripped the interior, cut almost all of the rust out of it, and am part of the way through preparing it to receive the new floor on the driver side. As of a few weeks ago, it still runs and the engine still makes oil pressure, so the oil pump rebuild was good.

 

I was most of the way through making a deal on a complete new drivetrain - new engine from an '87 XJ Laredo, external slave AX-15, NP231, and non-CAD D30, but it fell through just before it was scheduled to happen. I have acquired a full set of tan plaid interior fabrics and have found the correct paint color for the plastics.

 

The final plan is to make this truck either black or blue with a tan bucket seat interior. Install a refreshed (stock performance-wise; the goal is everyday reliability) Renix 4.0 (which I've already decided will be AMC Blue with silver highlights) and a 4WD conversion with an external slave transmission. Probably will re-gear it to 3.55 at that point too. Not planning on a lift, and probably will be keeping the 235-75-15 tire size, probably with the "rally" style wheels as I already have a set of those that just need a paint job. The goal is a truck that doesn't actively destroy nearby property values while remaining useful for my projected every-day use, which means a lot of highway miles with an occasional unimproved road and occasional light towing.

 

Since April, all of my automotive projects have taken the way-back seat. This will all happen when I feel like making it happen.

 

 

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