My 68 4-speed Charger that I bought 2 summers ago ran pretty well, or so I thought. The engine had been rebuilt and balanced several years earlier by the previous owner, but after I replaced the 3" exhaust and very loud Blowmaster mufflers with a stock system, I found that there was an engine vibration. So, I took the engine out and apart a few weeks ago and the first thing I saw after the intake was off was that several of the intake valves had oil crust build-up. When the timing cover came off, there was a standard chain and gear set in there plus a hardware store bolt and extra washer holding the cam sprocket on. The big washer on underneath the crank bolt was also a thin hardware store item. The rear main seal cap had a weird die grind in it and two freeze plugs had indications that they were weeping. Fortunately, upon full disassembly, I could see that the cylinders walls and crank journals were good. Keep in mind that this engine was rebuilt "professionally" by the previous owner's shop of choice out in Colorado.
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The heads went off to the machine shop & got a light valve job, refacing and new valve seals. I obtained the correct cam bolt, double roller timing chain set, crank washer and a new billet rear main seal cap, water pump, freeze plugs, gaskets, paint, etc.
The rotating assembly came back from the balance shop yesterday and the guy at the balance shop told me that the weight of the rods and pistons were actually balanced pretty good, but the previous balance shop flubbed up with the crank. He said that when his bob weights were on and they spun it, it was showing that they had to remove metal to outside some of the counterweights. He also said that on the rear of the crankshaft, it showed that metal needed to be added to the left of one of the rod journals where there was nothing, so they took metal from the counterweight opposite that point instead. Most likely, the previous balance shop made up the difference in removing weight from the flywheel with it bolted on, which now explains why the flywheel had so many drill holes in it around the perimeter of it. My guys balanced the crank with the bob weights, and then the balancer, flywheel and pressure plate balanced separately. After that, they bolted it all together and fine tuned it. He did tell me that he could tell that the amount of bob weight that the other guys put on had to have been off a little bit, but how much, I do not know. From other jobs I had done with them years ago, I remember that these guys are very fussy about their work.
You can see the grinding that was done by my guys (Lindskog Balancing) on the crank counterweights. Interesting to note that the other guys added weight (in the factory drilled holes), but Lindskog removed a bunch of weight on that same counterweight as well as some weight on the one next to it.
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These holes were drilled by Lindskog. The previous shop drilled a bunch of holes in the circumference of the flywheel below the ring gear.
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The pressure plate cover now has a couple of dime sized slugs welded onto it in the 9:00, 12:00 & 1:00 positions.
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I can't blame the previous owner because he brought it to a "reputable" shop for rebuilding. However, it just goes to show that there was some shoddy work done that he didn't know about. Looking through the slips I got with the car, the shop in CO charged $180.00 for the balancing job 5 years ago & my shop charged me $540.00 yesterday. I understand that things were cheaper 5 years ago, but it does go to show that you do get what you pay for. After looking at what was done, I have no doubts that this engine will run very smooth.
While apart, part of my plan was to convert the car from manual steering to power steering which has been done. I sourced most of the needed parts from placing want-ads here & the steering gearbox was sent to Steer & Gear for a rebuild and upgrade.
Special thanks goes out to Fran Blacker for letting me use his transmission tailshaft removing & installation tools, which allowed me to remove & reinstall the tailshaft bushing without pulling the 4-speed transmission apart. That was a HUGE time and effort saver.
So, tonight, the plan is to reinstall rods, pistons & oil pan. Tomorrow, the top end will go on & Friday, I'll paint it. )Got to take Thursday off for Valentine's Day.) If all goes well, it's going back in this weekend.