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1972 GMC K5 then and now

Overview Gallery Discussion
Wes Harden said:
Not having a lot of gen 1 k5 experience I need to ask, is the short water pump factory for a 72 ? I was thinking GM stopped using the short water pump in 69-70
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The cars changed to long water pumps in '69. The trucks changed in '73.
We still have the '72 truck that my Dad bought new. Short water pump since new.

I personally wouldn't swap to a long water pump unless going to serpentine belt arrangement. It keeps the A/C compressor on the passenger side, closer to the evaporator connections, unlike the long water pump, V-belt stuff in the later seventies which had the compressor on the driver side with lines going all of the way over the radiator and engine.
 
To fix the exhaust I cut out the Vband and flex joint with the plan to just weld in pipe.
The electrical in my garage is not reliable for welding and after struggling with it, I pulled out my generator. It worked but also wasn’t great. Took me hours to put in a little section of pipe that wasn’t leaking. IMG_2072.jpeg
 
After getting the exhaust patched my truck still ran like poop. I messed with the settings some more and hoped I could make it to Ashman’s the next day to load on his trailer for a trip out to Vernal for the Vernal Rock Rally
In the morning (Wednesday) it wasn’t any better, and arranged for him to pick up my truck and haul it out with the hope that it was an easy fix we could complete there.

On Thursday I checked in with the event and there was this yellow thing along with a ton of jeeps. IMG_2076.jpeg
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After check in, I went back and started diag on my truck. (Sorry no pics of this)
At our hotel there was a huge tree with shade just feet behind the truck but at this point it wouldn’t even start. I used my wife’s Jeep to pull the truck back and now in the shade, went through a check list to see what was causing the problem.
I checked fuel, air, and spark. Got tac signal on the Fitech.
The trails in vernal are short so about this time @Drummingpeke @kgblazerfive and @ashman were back and helped me run a few more tests. We used a spark tester make sure we had spark going to the plugs and the plugs had been replaced last year before rubicon.
The truck was cranking over but wouldn’t start. We tried starting fluid and messing with the timing a bit but no change.
At this point someone mentioned we got 2/3 of what an ICE needs. Fuel and air were given the only thing it could be was spark. So having already pulled a few spark plugs multiple time, I pulled number one again. We grounded it to the brake master with the spark tester inline. Cranked the engine, the tester lit up, but no spark from the plug.
We tried this a few times until I made myself the ground and personally experienced that the ignition system was sending spark :yikes:.
All the plugs had fouled. Swapped them out and it started right up.
We did a quick time by ear and drove it around. All seemed good and set to run trails the next day.
 
After missing the easy trail on day one, I jumped right into one of the harder trails called Doc’s Beach. At the meet up was this cool crawler/ hauler combo. IMG_2083.jpeg
The Jimmy ran great, but still a bit rich. I was seeing a lot of mid to high 12s on the afr. So it was better with room to improve.
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BYT didn’t like the trail
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And Twinkie was awesome!
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We were lead to a neat cave along the trail
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It was about this time Ashman noticed his axle tube separating and we carefully headed back to town.

I did take a minute to play with the twin stick and tried a front dig. It’s really cool to have the truck pivot around and have the front end pull without the rear pushing.
 
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The next day we were set to run on the Sand Bar trail.
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It’s a rather easy trail with many bypasses and just enough obstacles to make it fun.

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72gmck5 said:
That evening the Rock Rally had a few competitions like the RTI ramp, crawl drag, winch race, and car (Jeep) show. @kgblazerfive flexed out Twinkie and ended up in the top 5.
View attachment 479119
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I did score the highest for a leaf sprung truck, course I was the only one that tried it on leaf's ........
 
I noticed a leaky wheel cylinder on passenger rear of the truck and so tore down the axle to see what all I’d need to replace. Turned out the shoes were done and needed to be replaced too.
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The brake lines were seized at the cylinder and the axle tee. So those got cut off and after trying to finesse it off, heat, and even welding a nut on, I had to take it off and put it in a vice to remove the lines.
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So a wheel cylinder turned into two, with new shoes, and lines. Fully bled and feeling good once more.
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I also needed to find out why my turn signal lever wasn’t working. Popped the wheel off and the cancel cam was split down the middle.
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Since it was late at night and I needed to drive the truck in the morning I pulled it out and glued it back together.
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Reinforced it with a piece of zip tie on the outside edge to help it hold together. It’s pretty solid now and gives a firm engagement for the turn signal.
Might last longer than the replacement Dorman part I could have put in.
 
Bunch of little issues keep popping up. Probably from sitting unused for long periods of time.
I was experiencing an intermittent staring issue. It would crank but not fire. Come back after work and starts just fine. Decided to pull plugs and see if anything was up and found one of my wires had melted to a plug.
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Figured it had been a while since I’d replaced the wires so why not do it now.
Searched around and Amazon had a full set of ac Delco wires and plugs for just barely more than the plugs alone at Oreilly.
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Fired right up, barely turned once before it was running.
 
Are you thinking that the exhaust temps are melting the boots to the plugs?
I assume that you used dielectric grease before, as well as now.
 
6872xtc said:
Are you thinking that the exhaust temps are melting the boots to the plugs?
I assume that you used dielectric grease before, as well as now.
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Never melted a boot with headers on this engine before and I wrapped them last year. Should be less heat transfer now.
Also it was only the one plug. I pulled them all and only that one was hot and melty.
Might have just been a bad plug.
 
I use these.
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My plug boots after after about 9 months to a year would get sparkly dry and brittle and Crack and make it run like crap. It has been 2 years on these and I just changed plug wires since I pulled a couple clips off removing the wires. Boots were fine, I just reused the covers on the new wires.

Saw these on Mrk5's rig
 
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