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Old 04-21-2018, 10:45 PM   #1
jojo-munson
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Greenie the 72 C20

This is a thread to chronicle the adventure of getting my Papas old C20, "Greenie" into good shape again. Not sure where I want to go with her in the end, but for now I'm just trying to clean her up and get her reliable.

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Some backstory, my Papa bought this truck brand new back in 1972, making me the second owner. It spent most of it's time either with a camper on it in the mountains, or as a daily driver. Crazy enough it only has about 170,000 miles on it. The engine was either swapped out, or redone about 30,000 miles ago. Unfortunately, my dad doesn't remember if they put a new one in or just a re machined one so it's anybody's guess. Greenie sat outside, not moving, for about the last 10 years in the Pacific North West, which hasn't been kind to her. I spent all last summer working on her, every weekend that I wasn't working at the county. I had no prior mechanical knowledge, which makes this really fun. I love learning how to do all the stuff I need to for this truck.

The first challenge was getting her to start. So we replaced all the spark plugs, spark plug wires, distributor cap, starter, coil, and points. After doing all this we went to put fuel in the tank and noticed a big issue, lots and lots of rust.

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So we replaced the fuel tank and all the rubber fuel lines! Crazy what you can buy on Amazon. But still, she didn't start. Turned over real nice, but no spark. It took us over a month but we finally realized that the points were not actually opening and closing. So using a voltmeter we adjusted until they did. Fired right up after that! Oh it was beautiful. But terrifying. She smoked for a bit but stopped, we just figured it was some crud built up on the exterior of the motor burning off.

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By this time my summer was over and I had to go back to school to finish up my last semester of my degree in civil engineering, 300 miles and a mountain pass away. Go Cougs! After getting my diploma I wen't back to Greenie, changed the oil (which was blacker than midnight) and took her on her first drive in 10 years. My oh my was that a terrifying trip. She kept stalling and dying when I stopped in traffic, lights, etc... So to fix this I upped the idle speed until she didn't die at stop signs. Another issue was that her belts squealed at about 60 mph. But hey she ran and that's what mattered. She puffed a little white smoke at startup but it went away quick enough I always figured it was just some precipitation.

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I then decided to get a masters in environmental engineering, specializing in air quality! Because I just love student debt. So I replaced the belts and drove her 300 miles and across the snoqualmie mountain pass. Which is when I realized that alternator belt was way loose, because I couldn't drive over 50 mph without her squealing like a banshee. Man that was a long trip driving that slow. But hey it was an easy fix when I got home, just a slightly smaller belt and no longer a problem. I also got an electronic conversion kit and got rid of the points. Amazing how much better she sounded with those gone, and I was able to reduce the idle speed to near half what it was without her stalling.

Then a big issue popped up. Whenever I fired her up I was getting progressively more and more white smoke that lasted longer. Now this was during winter with lots of snow and moisture so I didn't suspect anything at first. But then she started puffing white smoke after being warmed up, turned off for 5 min, and then turned back on. I first checked the antifreeze level in the radiator, and yup, real low. Yay. So I figured I'd pull the heads off, inspect/clean them, and hopefully just have to replace the gaskets. But the last bolt I went to remove on the driver side exhaust manifold sheared off. So after some advice on here I'm going to try and unbolt it from the pipe and lift off the manifold when I take the head off too.

But the nuts holding the manifold to the pipe are so rusted, they're a little round. So the meager grip I can get on them with a wrench, will slide after too much force. I ordered a propane torch to try and heat them real hot, then I'll let them cool and try again. In the meantime I'm spraying with penetrating oil. If that doesn't work I may just have to get my dremel up there and cut the nuts. Another fun tidbit, of the three nuts that are supposed to be there, there are only 2. If I had the spare cash I'd just order a pair of headers from summit and cut the thing off, but that's not an option quite yet, as I may need the cash to get the heads re-machined or buy new ones.

Anyway's, that's my story so far! I'll ad pictures and events as I continue working on Greenie. Thanks for reading!
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Old 05-06-2018, 07:00 PM   #2
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Intake Manifold Removed

I finally had the time and was able to get out and work on the truck some more. Pulled off the valve covers and found a nasty surprise, some white gunk.The worst of it is on the drivers side, although the passenger side a little as well. No where near as bad however.

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I also got the intake manifold off. Luckily I've been spraying all those bolts with penetrating oil and they all came out without too much fuss. Man did that suck trying to wrangle that hunk of metal out by myself. I've started taking the rocker arms off the heads, but the washers are getting stuck, making it a tougher part of the job than I thought it'd be. Hopefully tomorrow after work I'll be able to get the rest of the rockers off and unbolt the heads so I can send them to get cleaned up and re-machined.

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Old 05-06-2018, 07:10 PM   #3
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Re: Greenie the 72 C20

Very nice!!!
You are going about things in a good fashion, my opinion.
I'm guessing that you've changed the oil at least once, and it did NOT look anything like the insides of the valve covers???
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Old 05-06-2018, 07:19 PM   #4
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Re: Greenie the 72 C20

I've changed the oil twice, once before I started her the first time, and then again after driving her about 100 miles. Neither time did it have any white to it. The first oil change was pretty terrifying, the oil was blacker than I thought black could be haha.

But I'll most definitely be changing the oil and filter before I start her again.
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Old 05-21-2018, 12:04 AM   #5
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Re: Greenie the 72 C20

Bought a crowbar and finally got the stuck exhaust manifold off. Not exactly the way I was hoping it would come off, but at least it's off. If I had the spare change I would upgrade to headers, but as a poor college student I'll just be replacing it with a standard exhaust manifold.

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After the exhaust manifold was off it was real easy to unbolt the heads, thankfully. However there was a lot of coolant pooled on a couple of the piston heads. Pictures below show their condition. Pistons 5 and 6 both are really discolored and had pools of antifreeze in them. I'm no expert but they don't appear to be cracked, so I may just roll with them.

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Heads go off to the shop tomorrow to be cleaned and machined, so hopefully I'll have a running truck in the near future. Yellow jackets are out, and I even had to crush a small nest they were making under the hood, so getting this engine back together will hopefully happen soon.

On a side note, at top dead center, my distributor rotor was pointing at the number 2 spark plug. But in all the videos I have watched, it's supposed to point at the number 1 spark plug. Should I try and put the distributor back in pointing at #1, or put it back how I found it at #2?
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Old 06-03-2018, 09:09 PM   #6
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Re: Greenie the 72 C20

Both the heads that were on the truck were cracked, good sized ones. So that was a real bummer. Not a cheap fix haha. I took it as an opportunity to do some upgrades, in this case to a set of vortec heads. My local machine shop gave me a decent deal on a brand new set. Though it wasn't until I got home that I thought to check which casting they were, and they turned out to be 906's. I did a lot of reading and there seem to be many controversies over whether the 906 casting is inferior to the other. Either way, they'll be an improvement over the old heads.

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I quickly realized that even though the vortec heads cost the same as a new set of the old style, all the accompanying parts really started adding up in price. I got a new intake, valve covers, water neck, thermostat, self aligning rockers, all the gaskets and associated bolts, drivers side exhaust manifold, and spark plugs. This ended up being about a $1,500 upgrade, but that's mostly because I decided to get quality parts like the Edelbrock intake, instead of cheapo ones. I had to special order the bolts for the exhaust from Ace, so even though almost everything else is put together, I have to wait on those. I'm really tempted to just throw on a couple of the old rusted bolts just so I can see if she runs.

The other setback is that I dropped the throttle return spring somewhere in the engine bay. No idea where it went, and I spent a good hour looking for it. So I'll need to pick up one of those.

I have a Rochester quadrajet, but the intake manifold I have doesn't work with the divorced choke. So I'm going to see how well she runs without a choke. I did some reading and it seems that it means I'll just have to sit there with my foot on the gas until she warms up for a longer time than usual. I also need to bend a bracket to get the kickdown to hook up.

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Old 07-14-2018, 09:35 PM   #7
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Re: Greenie the 72 C20

Finally got her running! She has a nice deep rumble to her. Running without a choke doesn't seem to matter much right now, nice and hot outside. After I got everything together it was loud as hell and had about zero power going uphill. I tried messing with the timing a crapton to fix it. Until I finally realized I needed to get a vacuum gauge to accurately diagnose anything. The gauge jumped super fast between zero and 15. Which means I had done a real junk job of adjusting my valves. The method I used was getting to top dead center and doing half, then rotating to the opposite TDC, and doing the other half. While this method got the engine going, it wasn't good enough. So today I did it the hard way, rotating the engine by quarters and adjusting each valve individually. Purrs like a tiger now! Well, when I rev it a bit at least haha. Only issue now is that I'm only getting about 12 for vacuum. But I'm thinking it may be the old quadrajet, since ive checked everything else for leaks and replaced all the rubber lines.
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Old 07-14-2018, 11:16 PM   #8
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Re: Greenie the 72 C20

Good for you man. Thats always a boost in the morale when you have such a positive result. Ya gotta love the way these old v8's sound at idle when they run right!
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Old 07-15-2018, 11:17 AM   #9
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Re: Greenie the 72 C20

Thanks! That's for sure, heck of a lot better than the 99 saturn I have.

I lucked out and a family friend has a spare Holley carb. The carb is in good condition, they just wanted to convert to fuel injection. Hopefully I'll get that carb later this week in the mail and put it on the truck, see if that helps any. Either way it'll be a free upgrade!

But if this carb goes on right, Summit sells a complete kit of headers, exhaust pipes, and mufflers to do a dual exhaust for only $350, so that'll be the next project. The replacement Dorman exhaust manifold doesn't actually match up to my pipe so there's a massive exhaust leak in the engine bay. To completely replace the pipes, will I need to jack the truck up at all? I feel like there should be enough space to sneak the old one out but I'm not certain.
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Old 07-25-2018, 07:51 PM   #10
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Re: Greenie the 72 C20

Got an Edlebrock AVS2 carb and put her on the truck. Immediately solved my vacuum, and idle issues. She was idling at 500rpms before I upped the idle a bit. But that's crazy to me, since before this new carb, pretty much anything below 950rpms risked the chance of her dying. Granted the 500rpm was pretty rough, but i upped it to about 850rpm and she smoothed out. She's currently timed at 8 degrees, so now that I can idle her low I'll have to go play with that.

Another note to make is that the fuel pump started spurting gas out the side a day or so before the new carb came in, so I replaced that too. Had to actually saw off the metal line attached to the old pump. Which was okay since I was going to have to do it anyways for this carb conversion.

Took her out for a single short drive and everything seemed great, so we'll see what crops up as time goes on. Hopefully nothing soon!

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