1975 GMC Glenbrook

I did a little bit of tinkering with the coach the other day, as I figured it was time to make sure it was somewhat winterized since we've been getting some morning frosts.

Back when I was testing the 12V house system, I ran the kitchen sink a bit to see if the water pump worked. It did, but the sink never drained. Since I needed to make sure all the drains were clear, I set about figuring out what was happening. It wasn't a backed-up system, since that would've caused the the shower drain to over flow. So I started trying to snake the drain. I could feel something semi-solid in the pipe in the trap area, but the water wouldn't drain no matter how many times I poked through it. Eventually, small bits of coagulated grease floaters made their way to the surface. I soon realized the previous owner had completely filled the drain with grease and let it set up. So I boiled a large pot of water, filled the sink, and pulled the plug. It worked it's way through reluctantly. One more pot got it flowing reasonable well. Eventually, I'll have to run a ton of hot tap water through there, but that will have to be later.

I also got the macerator up and running, and was able to drain the previous owner's "leftovers" into a sewage cleanout about 40' away. I didn't want to soil a good garden hose, so I picked up an $8 roll of that black poly tubing just to get this thing emptied out. At least it's a hose my wife will never accidentally use to set up a sprinkler for the kids...

Overall, the plumbing seems fairly functional, albeit a bit sloppy. I'll be redoing things properly at some point, but it's at an OK starting point for now. I definitely saw some drippage around the macerator while it was running, so I'll have to investigate that once I get some ramps for this thing.

Once mystery is, I can't really tell if I have a water heater or not. I probably ought to look into that.
 
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I got a new keychain! Hey, it's progress, right? I kept getting the GMC keys mixed up with our other P30 based motorhome, so now that's sorted. Besides, I just had my gallbladder taken out at the beginning of the month, so my activities have been limited.

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In other news, I drove 5 hours up to Washington to take a tour of the three GMC Davids up there. I got a whole truckload of parts, and nabbed a "new" minivan for the wife on the way home. It was a busy weekend.

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The truckload of parts includes but is not limited to:
  • Rear setee folding benches (needs reupholstered)
  • Folding dinette benches (needs reupholstered)
  • Davo/couch/bunk set (needs exorcised, then reupholstered)
  • Grille
  • Headlight and turn signal
  • Headlight bezels
  • "New" reproduction fiberglass front nose
  • Carved out section of wheel arch to go with front nose
  • Front left "hood" panel
  • Front left bumper
  • Furnace
  • Propane tank with seemingly functional resistive gauge sender
This ought to be enough to keep me busy for a while. I'll still need a new windshield though. Now I just need to source some fiberglass repair materials. I'm thinking of going with the Evercoat SMC-specific polyester. They really seem to insist that it works great for SMC repair, but I'll do some more reading before I throw $50 their way.
 
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In your photo it shows an edelbrock 1406, it's only a 600cfm carburetor, set up for fuel efficiency. I put one on a 454 Class A motorhome once and thought it ran pretty good. Then I put on a 1411 750cfm and it was quite a bit different. Much more hill climbing ability. I think you're starving the 455 Olds motor with the 1406 carb. Now that you have the fuel pressure problem worked out it would be a good idea to go back to the original Qjet imo. If I knew then what I know now I would have just rebuilt the Qjet lol

If you want to find TDC for timing your motor, there is a piston stop tool that threads into Cylinder 1. Very inexpensive and very accurate. With all the plugs out of the motor, you rotate by hand, first one way until the piston comes up against the stop where you make a mark on your timing tab, then the other way and make another mark. Halfway in between is TDC 0.0 degrees. Do it when you change spark plugs since you'll be taking them all out anyway.
 
tmsnyder said:
In your photo it shows an edelbrock 1406, it's only a 600cfm carburetor, set up for fuel efficiency. I put one on a 454 Class A motorhome once and thought it ran pretty good. Then I put on a 1411 750cfm and it was quite a bit different. Much more hill climbing ability. I think you're starving the 455 Olds motor with the 1406 carb. Now that you have the fuel pressure problem worked out it would be a good idea to go back to the original Qjet imo. If I knew then what I know now I would have just rebuilt the Qjet lol
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No question about it, the first thing I'm doing on this motor is going back to that nice rebuilt Quadrajet. That Edelbrock is better suited to a Nova with a 350. It isn't even spread bore! No wonder this thing had a hacked together engine cover that sits up too high. He had the carb adapter AND a thick phenolic spacer, in a feeble attempt to make his pressure related carburetion woes go away. I'm a big Qjet fan anyway, and have rebuilt several over the years rather than swapping in something aftermarket. I can't wait to see this thing go up a hill at 4000 feet faster than 20 MPH.

I think once I determine TDC on the engine, I'll make my 0 degree mark on bottom side of the engine. My timing light has that compensation dial, so I won't need that flopping scale anyway. I just need to make that initial, reliable reference mark.

I haven't seen the tool you describe, but it sounds like a great idea. I've definitely used the screwdriver in the cylinder though the spark plug hole before, but the accuracy is very questionable. I was thinking about inspecting the chain and doing it then, but I like your idea.
 
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tmsnyder said:
they are cheap, something like this one which says for small block chevy.

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Does Olds use the same plug thread as SBC?
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I would assume so. Pretty much every time I get out my compression tester, I never have to use the adapters. Spark plug threads seem very standard (though not SAE). I think they've all been metric since the 40's, oddly enough. I'll go ahead and pick up one of those tools. Thanks for the link.
 
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What an adventure. You sure make the Roadkill guys (and fans) proud. Reading about you wire to fuel pump change color several times and go through multiple fuses, totally hits home. I've been rewiring the rats nest under my dash board. It seems like every wire was connected to a wire spool before splicing into some other wire... You can imagine how much more room I have under there, now that the extra wires are removed. But I have to admit - Igot off easy since I did the repairs in my driveway, not in the middle of who knows where NV...0521192010.webp
 
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I picked up a toad for $500 today. 2900 lbs, 4x4, 5 speed, 160k, and four doors. I kinda wanted to pick up a Fiat 500, but don't know where we'd put our husky, and the wife wants 4x4 in case it's needed to get to trailheads. Maybe I'll snag one anyway as a cheap daily driver. I'll need to build a new hitch for the GMC, then add a baseplate and a towbar to the Suzuki.

It currently doesn't start. Seems to have compression, I'll try to measure it tomorrow after the battery charges. The spark plug wells were full of oil--could it be that simple? The crank sensor is inside the bell housing on this motor, so fingers crossed that's not the problem...



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Russell said:
Wow!! and I thought WE had time chain issues...
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Yep, you never want to ignore a timing chain rattle/slap. It fatigued the guide, then sucked it right into the gear! I was just tracking down a lack of compression and figured I'd pull the valve cover. It was really in-your-face sitting there like that. On the plus side, doesn't that valvetrain look CLEAN? Hard to believe that's what 160k looks like.
 
Do you think it's got bent valves based on the timing chain problem? Seems like it must have banged into some of them when that chain tensioner let go....
 
tmsnyder said:
Do you think it's got bent valves based on the timing chain problem? Seems like it must have banged into some of them when that chain tensioner let go....
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Indeed it does. The borescope showed four shiny spots in the carbon on top of #1. Got every valve on that cylinder. The other cylinders only have two shiny spots per piston, so that's a bonus. A leakdown test revealed about a 30-40% leakage rate too.
 
I started doing the carb swap to switch back to the Quadrajet and discovered I have a cracked intake. Also, it seems I already have Mondelo type exhaust crossover block off plates. I'll probably get a new set of gaskets so I can pull the manifold and weld it up.

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The improperly selected Edelbrock was a square bore, mounted with an adapter AND a thick phenolic spacer. No wonder they built a raised engine hatch.

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The wife has gotten a bit antsy about the lack of progress, so she's started gutting some of the interior in the central area. Don't worry, nothing is original, and it was all poorly done.

Racing stripes made out of church pew fabric?

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Someone's idea of carpentry? This is one of the platforms for the jackknife sofa.

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Some of the wall panels are rotted in the corners, but as luck would have it, the subfloor is solid despite some staining.

The wife also found some LVP on Facebook that is actually guaranteed from -20 to 150F. I've not seen a manufacturer claim that before, and it's actually US made. When scoring and snapping, I can see it's loaded with glass fiber. Maybe that gives it some stability.

I started running it diagonally. Longitudinal is most prone to gapping with thermal changes. Transverse just looks like the wrong way to me. So, diagonal seemed like a neat option. I regret it due to the increased effort required, but it's too late now.

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There was one soft spot where the original dinette bench would have bolted down near the door. The rest of the subfloor was solid, and I didn't feel like playing around with all the rivets, sourcing new wood, cutting, installing, etc. I decided to experiment with some wood hardener and high-performance filler. I've got to say, I'm pretty pleased with the results. It's plenty strong enough for these purposes.

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The wife ground down the tops of some carriage bolts just in front of the door that were standing proud of the subfloor for some reason.

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Afterwards I finished off the floor in the forward dining/sleeping area. There was an intentional hole where a steel spacer sat and the seat was bolted through, so I used a similarly sized piece of PVC to mold the hole into the filler material so I won't lose track of the mounting locations (I'm also not a fan of drilling out holes from underneath).

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Next I'll move rearward through the galley to the back room. First, I'll need to figure out why the floor in the back room is raised with extra foam and plywood. I'd prefer it to be flat all the way back...
 
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