cruiser
Well-Known Member
Hello MoBros and MoSis': I trust you've all been sleeping well since the most recent sleep inducing chapter of my component resto articles. Just when you thought you were rid of me, I'm back at it again with the biggest project of this series - a new engine for Dusty. But first a little background. When I bought my 1974 Gold Duster in April of 2019, it came with a replacement engine that was installed in 1988 after the factory original motor failed. The replacement engine came from a parts store in Portland OR, and as such I cannot attest to the quality of the rebuild before it went into my car. It seemed to be running pretty well when I bought the car. In any case, the replacement motor started running badly earlier this spring. It seemed to be misfiring, running rough and was shaky at highway speeds. At first I thought that it had lost a cylinder, but I later determined that all six were firing. Checking the vacuum at idle showed a pretty shaky needle, and a compression check revealed that cylinders three and six were way low (first photo) - which was also verified by a leak down check. I've been working with a very skilled and experienced engine shop here in Minneapolis and the inescapable conclusion was that the engine was failing after 135K miles likely due to bad piston rings and/or valve problems. Fortunately last fall, I acquired a complete, dressed long block slant six from a December of 1973 built 1974 Dart. I was told that it was running when pulled with approximately 83K original miles on it and that a crate V-8 was going in its place. At first I considered just swapping the Dart engine into my car. After all, the Dart engine is slightly more correct for my car as it was cast and assembled closer to the build date (October of 1973) of my Duster. But since I plan on keeping the Duster forever, I made the decision to go ahead with a full teardown and rebuild of the Dart engine. Starting with a clean slate, I would finally know exactly what went into the engine. The second photo is the Dart engine on the ground where I picked it up, and the next two are what it looked like when I got it home on a stand. I soon determined that the exhaust manifold was not usable due to a crack, seen in the fifth picture. The next photo shows the components that I pulled off. Since the Dart was a factory air car, all the a/c related components (compressor, steering pump, dual pulley alternator, etc.) will end up being sold as I won't need them on Dusty. The new engine then went to the shop for a full teardown and cleaning prior to heading over to the machine shop where the block and heads will be Magnafluxed prior to machining. See the final three photos. So that's where we stand right now. Chapter two will cover the machine work when finished, and chapter three will be the rebuild, installation, break-in and driving impressions. In the mean time, I'm looking forward to a new life for Dusty with a smooth, quiet and dependable motor under the hood that will take me anywhere with confidence. In the mean time, here's the info on the Dart motor for you numbers guys/gals: On the right front top of the block 3W 225 4520 (Windsor ONT engine plant, 225 cubic inch block, Dec. 12, 1973 build date), On the right rear top of the block 4G172603 (last eight digits of the VIN from a St. Louis built 1974 Dodge Dart), On the left side of the block 2806830-4 BH AAWJ (the casting number for a high deck forged crank block cast on Dec. 1, 1973, -4 denoting the casting pattern number with BH indicating an engineering change of extra side ribbing, and AAWJ identifying this block as being cast at Chrysler's Huber Foundry in Detroit), On the lower left side of the block - an arrow pointing to the number two (meaning that the block was cast on the second shift), On the cylinder head - 2843169-4 (cast on Nov. 29, 1973). As you can see, the casting numbers for the replacement engine are all correct for my car although the cast and build dates are still a bit too late for my October of 1973 built Duster. But this is about as close as I can get fifty one years later, and these dates are a lot closer than the build date (summer of 1974) of the engine coming out of my car. So there you have it. Sleepy yet? Good. Now get your milk and cookies and march right upstairs to bed!
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