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G/MAN
02-06-2007 10:56:55
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Re: Cost of older JD diesel overhaul?? in reply to jdemaris, 02-06-2007 08:11:48
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I think we're on the same page. It would not bother me in the slightest to "have" to do pump work, rebuild cylinder heads, etc. But I can understand our policy to farm that work out. We have two excellent machine shops here in town. We deal with one primarily, but don't hesitate to use the other when the other gentleman is on vacation. The bill for planing and recondition that 8200 cylinder head and for replacing the pin bushins and fitting the pins in the connecting rods was $250 - a shade less than 4 hours of labor at our current shop rate, and no doubt he had more than 4 hours in that job, were we equipped to do the work. Grinding valves is one thing - planing a head and reconditioning rods is quite another. I've seldom run across rods that required big-end work unless they were earlier rods that needed to be honed for torque-turn bolts, but we replace the pin bushings without fail, and it's my understanding that the bushings have to bored and not simply honed in order to maitain the proper center-to-center dimension and keep the piston properly located and the compression ratio correct, just as the valves have to have the proper protrusion. It would take dozens of overhauls to recoup the investment in special tools and training it would require for us to do that work in-house. And I've never, ever considered myself a parts-replacer. I was very lucky to attend one of the first and best tech schools in the nation and take Diesel Technology Truck and Construction Equipment there at a time when the instructors were all seasoned veterans of the automotive and diesel industries and at a time when the curriculum was very heavy on fundamentals and proper procedures. Our first two quarters were spent on the exact same curriculum as the Automotive Technology program, so we did carburetor work; distributor, generator, alternator and starter repair, computer command controls, etc. We had to take a basic hand-tools class that involved learning how to properly use micrometers and other measuring equipment, care and maintenance of tools such as drill-bit sharpening, and we even learned and had to practice flaring tubing and sweating copper tubing. During the engines class, we were required to completely disassemble one of the test engines and make and record every critical measurement on every component - crank journals, camshaft lobes, valves and guides, etc. - and then calculate clearances and so forth using those measurements - slapping on a piece of Plasti-Gage wasn't an option. We spent a full quarter just on diesel fuel systems - Cummins PT, Detroit 2-cycle, Stanadyne, Robert and American Bosch, etc. Rebuilding and calibrating pumps, reconditioning nozzles. Spill-timing pumps, running overheads and all the rest - been there and done that. And this sort of thing went on for 18 months, 8 hours a day. The focus was proper procedures and fundamentals and using that knowledge to develop your job- and industry-specific knowledge and ability from there. Unfortunately, they radically revamped the program a year or so after I had graduated, and I doubt anybody graduating from there now has ever had a distributor on a test stand to check the advance curve or has ever seen or used an armature growler, let alone seen the inside of a Detroit 2-cycle injector. By modern standards, we still do a great deal of our work in-house. I worked for a Caterpillar dealership on heavy-equipment for a few years, and an engine overhaul there usually consisted of reusing the block and the crankshaft and replacing everything else with Reman components - water pump, oil pump, cylinder head, liner packs with the connecting rods included and pre-installed, etc. I can also understand the efficiency benefits of farming work out - taking that cylinder head and rods to the machine shop afforded me the time to finish the engine disassembly, clean up the block and other parts and have the crankshaft installed and ready when I got the rods and cylinder head back. Yes, there is a markup on outside labor, but I'd bet dollars to donuts that if you applied our shop rate to his labor hours (the labor hours of a professional machinist no less), you'd come up with a total far exceeding even the marked-up cost of the work we farmed out. I'm able to get the job done more quickly and move on to the next segment or next project, which is important as I normally have 3 or 4 projects going at once during the winter when things are "slow". During planting and harvest when I spend about 7 months a year working out of a service truck, it's not uncommon to work on 5 or 6 different machines per day. And I love every minute of it. So I'm not a parts replacer and I know I have the knowledge and ability to do the complete job top to bottom and front to back, I just don't have the opportunity to use those skills all the time. Not to mention the more modern and new technology that the independent guys never get to see or work on.
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