How to Resurrect a Dead Big-Block Chevy Vortec 454 (L29) Engine

    Trying to Revive a Chevy Vortec 454

    Bad ideas? We've had them, and probably will continue to have them despite our best efforts. Like a junkie, we always seem to be looking for that next fix, only our heroin comes in the form of trucks and 4x4. We're not junkies—we're junkys. We crave capable off-road rigs both big and small. And like most addictions, it creates a problem.

    The problem is money, the root of all evil. We apparently would prefer to spend it on many ragged pieces of 4x4 crap than one or two nicer 4x4 pieces of crap. We hoard derelict off-road vehicles and projects in hopes that we can one day take them on an adventure off the beaten (more like "off the paved") path. That's why free or nearly free trucks and 4x4s are very hard for us to refuse.

    This is the exact problem with the 1997 Crew Cab Chevy 3500HD truck that is the focus of this article. It seemed free, a deal too good to pass up.

    Of course, working at the world's largest off-road magazine only enables our habit, justifying some, if not all, of our projects because we need them for work. (Yeah, that's it!) We introduced this truck to you before, and we even started collecting parts for the build, namely the locked and loaded 2 1/2-ton axles we plan to tuck under it. It's a free truck, which is one of the most sought-after trucks for people with our particular addiction. And while it's not four-wheel drive (yet), it does have a 454 engine, a beefy transmission, and solid front and rear axles. That's right—leaf-sprung beam front axle. These issues, we've convinced ourselves, are easy to overcome given our current path of enabling our addiction, even if it means spending money on a free truck. But at what cost really?

    Here's evidence that this Chevy 3500HD hasn't moved in many years. It was last registered in 2002. That means there is a good chance it has been parked since then, but why? It's a 1997, so it was only 5 years old when it was parked and only has 112,000 miles on it. This truck, along with two others like it, were sold to our buddy as assets when a company that owned them went bankrupt. This buddy, Mike, basically told us that if we can get the truck running we can do with it what we want. We're thinking big tires and Rockwell 2 1/2-ton axles!
    With a truck that's been parked as long as this one has been, you've got to start with the basics. First, we had to see if the engine would turn over. From there, most engines want to run, but need fuel, air, and spark. First step was to hook up a battery and turn the key on the old truck. We popped a Duralast Platinum Battery AGM Group Size 78 with 740 CCA ($194.99 with an $18 core) into the battery tray and hooked up the terminals. The engine turned over, and a spray of starter fluid gave us a sputter of life. So that's good news. The engine cranks and we have spark.
    We have spark, but oddly, several of the spark plug wires had been pulled off the engine, and some were damaged. We were not sure what to make of that. We'd probably replace the plugs and wires on an engine like this that has been sitting idle for this long anyways, so meh! Duralast Wireset (PN 4639, $38.99) fits the bill and the truck.
    We also tossed in a Duralast Gold Ignition Cap and Rotor Kit (PN DR2031G, $56.99) for good measure—and that was a good call. The cap on the truck looked OK, but the rotor wasn't properly tightened in the distributor. As a result, the holes had wallowed out. We're guessing that didn't help performance on the old Vortec 454.
    Since the engine didn't run on its own, the next step was to make sure it was getting fuel, and to make sure the fuel is getting to the engine. With the key turned, we checked for fuel and fuel pressure at the port at the intake manifold. Nada, no fuel. Our next step was to check the fuel pump relay, which we could feel clicking with the cycle of the key, so the pump should be running. From there we needed to establish why the pump wasn't running. We located the factory plug that sends wires to and from the fuel pump/tank and checked for voltage, which was present with cycling the key. Next, we dropped the tank and pulled the pump and found that the pump and primary filter (fuel sock) were absolutely gummed up with about half a pound of some tarlike substance. Maybe the remainder of 15-year-old gasoline?
    Freelancer Trent McGee is a great friend to have, and for reasons only he will ever know he's the one who ended up cleaning most of the remaining "tar" out of the Chevy's fuel tank using fresh gas and rags. (Thanks, Trent! Sorry, Trent! Now that it has been several weeks, does your hand still smell like old gas?) Poor bastard. A good friend is worth his weight in gold.
    With the tank dropped, we installed a Delphi Gasoline Fuel Pump (PN CFE0114, $72.99) from our local AutoZone store. And with the new pump installed, about 3 gallons of fresh gas, and the tank roughly back in place, we cycled the key. Now we were reading just over 60 psi at the fuel rail, which is just where we want the fuel pressure but still, we lacked fire.
    We surmised that the fuel injectors were probably not firing, so the fuel, although at the rail, was not getting into the intake and thus not entering the combustion chamber. This could be because of a lack of signal, or because the solenoids in the injectors were gummed up from old fuel. The first step is to test for a fire signal at the injector, and the easiest way to do that is with a set of noid lights, but that meant removing the upper intake manifold. Our noid light test confirmed that the injector was getting a "fire" signal, so the next step is to pull and replace, or clean, the injectors.
    We found a local shop, Rods Carburetor in Phoenix, to clean and flow-test our injectors. At $120 for all eight, the service was a steal since most injectors that will work for this vehicle range from about $120 to $60 each. We reinstalled them in the fuel rail and put the upper intake back together to see if the rig would run.
    We got everything buttoned back up, including a new Duralast Serpentine Belt 1005K6 ($25.99). With the freshly cleansed injectors in place, we were feeling pretty confident that the truck would fire right up. But we were wrong. The truck cranked away but wouldn't catch and run. At this point our story goes from hopefully optimistic to frowny face.
    From here we decided to hedge our bets. That started with verifying that the distributor was installed correctly, so we mechanically rotated the engine until the timing marks for TDC on the harmonic balancer lined up and checked the distributor. It was wrong. Another 180 degrees of rotation still yielded, at best, a timing conflict. So we pulled the driver-side valve cover in order to verify that the engine was at TDC. What we instead verified was that the engine wasn't going to run easily without more work. A pushrod was bent (see the video) and an exhaust valve was stuck open—and that valve has almost certainly come in contact with that No. 1 piston while we fruitlessly spun the engine trying to get it to run. As they say, nothing is free. The good news is our buddy Mike has a nearly identical truck with a nearly identical Vortec 454. And while we haven't made a solid decision on what course to take next, maybe we'll try to start a different free truck that's also been sitting for 15 years. What have we got to lose?
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