We had blue smoke and a maiden voyage yesday! First time this truck has gone around the block under its own power since 1976.
I took Aston51's block draining tip from oldgmctrucks.com and I'm really glad I did. I had already drained and flushed the system (or thought I did), but the block drain behind the exhaust manifold was just seeping some nasty looking crap, not really flowing. I completely pulled the drain valve off - still almost no flow. Got a piece of heavy wire like he suggested and started working that sucker around in there. A big blob of some particulary nasty crap cleared and then you should have seen the rusty water run out. Lots of solid, sandy looking crap in there - amazing that the engine wasn't overheating (who knows, maybe it was in '76). OldCarKook suggested that it's the leftover casting sand from original assembly. Kept refilling the radiator after replacing the drain, then pull the drain and work with the wire some more. Finally got a consistant clear stream of water. Then I used 2 bottles of Prestone Fast Flush, filled the rest of the way with water.
Cranked her up - almost ready to go. I've got new points, plugs, rotor, dist cap and condenser in, but the truck idles roughly. Wires were replaced a long while back (10 years?), but look good. I went to each plug in turn and pulled the wire. I could hear the engine roughen slightly as the plug didn't fire. Didn't find any dead cylinders. Accelerator pump is gone in the carb, so you've got to do a bit of gas pedal jiggling to keep it going as you give it gas. Not sure what's causing the rough idle.
Now, time to tackle the dreaded driveway. We taped the whole process this time and, if I can figure how to do it, I'll post it. Brakes seemed a bit grabby, but working fine to go down the steep drive. No exhaust system, just a short exhaust stack stuck on at the manifold, so it's LOUD. Steering remarkably tight (makes me believe the 24,998 miles on the odometer). Synchros in the trans feel good, but shifting is a bit stiff. All gears working with no weird noises, no jumping out of gear.
Pulled a few hills in 2nd and the truck pulled great. I expected the rough idle to translate to missing and skipping under load, but it just didn't happen. She pulls like a Trojan when you give her some gas. Anybody got any ideas about this missing at idle? Got a Zenith carb rebuild kit on the way since I know it's needed, but wondering if it might help with this problem. Maybe valve adjustment? Any opinions welcome.
Got back home and couldn't back her up the steep drive because the truck was so light in the rear (all the wood's rotted away). Spun tires and played hell for three tries before I gave up and came up front first. Let her cool completely and then pulled the block drain. Another load of rusty looking crap came out. Flush, fill, flush, fill until water is clean.
Well the plan was to go around the block under power before Christmas - got her done with 10 days to spare. Merry Christmas to me.
David B
