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How to assemble a shortblock
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<blockquote data-quote="SlowSVT" data-source="post: 8259083" data-attributes="member: 20202"><p>Malcolm</p><p></p><p>Sounds like you are being very careful and asking the right questions. There is a lot going on here but something tells me you are in unfamiliar territory. The .0035 - .004 PWC which is almost 4X the factory clearance which is safe up to 550-600ish HP seems a bit loose where I would probably opt to keep it in between .0025 - .003 depending on your power level you are trying to achieve. A torque plate severs no purpose when setting ring gap especially when the head bolts reach down into the block which is done to minimize cylinder distortion at the top of the block. Having a little too much ring gap is better then less especially if the motor is going to make lots of hp and heat. If the ring expand and bind it can score the cylinder, break or possibly damage the ring lands.</p><p></p><p>"Blue printing" the engine is a very involved process and goes way beyond what most people realize. A set of blue printed rods can cost over $1000 and usually is done using multiple sets of rods and QC'ing all of them to get a set that match the closest. The will weigh each end of the rod, measure for taper and alignment between the big and small end, roundness, twist and probably a host of thing I didn’t even think of and that is only the rods. You are also relying on the accuracy of the measuring tools and the guy working the micrometers and gauges. Measuring machined parts are just a much of an "art" as it is a discipline. Also the machine shop boring equipment may be worn or improperly positioning or clamping the parts can have bad effects. Just because they advertise that they build race engines does not guarantee they are doing it correctly or accurately. I have worked down to .0005” and things get real hairy in that realm. My experience is the factory usually does the best job because their machines are designed specifically to do only one job and it is very expensive if they machine a lot of parts incorrectly that will come back to haunt them with warranty repairs so they are real big on QC. The .001” PWC is a perfect example. Imagine what the results would be if they were off by .0005 which is 1/5th the thickness of a human hair and that all the way down the bore from all directions. One of my vendors runs their machines for half an hour to get it up to operating temperature to stabilize the machine before the cutter event touches the metal. There is a big difference precision machine shop and a guy with a boring bar. </p><p></p><p>The iron block will hold machining accuracy better then aluminum because it is stiffer, has 1/2 the expansion rate and will heat more evenly throughout the block. So there is less to worry about. </p><p></p><p>The factory shop manual is your best friend here but some of the parameters may change somewhat if your modding for more power. Do this one step at a time, post your questions and don't take any one persons word for it including mine. Cross check your answers before doing anything and you should be OK</p></blockquote><p></p>
[QUOTE="SlowSVT, post: 8259083, member: 20202"] Malcolm Sounds like you are being very careful and asking the right questions. There is a lot going on here but something tells me you are in unfamiliar territory. The .0035 - .004 PWC which is almost 4X the factory clearance which is safe up to 550-600ish HP seems a bit loose where I would probably opt to keep it in between .0025 - .003 depending on your power level you are trying to achieve. A torque plate severs no purpose when setting ring gap especially when the head bolts reach down into the block which is done to minimize cylinder distortion at the top of the block. Having a little too much ring gap is better then less especially if the motor is going to make lots of hp and heat. If the ring expand and bind it can score the cylinder, break or possibly damage the ring lands. "Blue printing" the engine is a very involved process and goes way beyond what most people realize. A set of blue printed rods can cost over $1000 and usually is done using multiple sets of rods and QC'ing all of them to get a set that match the closest. The will weigh each end of the rod, measure for taper and alignment between the big and small end, roundness, twist and probably a host of thing I didn’t even think of and that is only the rods. You are also relying on the accuracy of the measuring tools and the guy working the micrometers and gauges. Measuring machined parts are just a much of an "art" as it is a discipline. Also the machine shop boring equipment may be worn or improperly positioning or clamping the parts can have bad effects. Just because they advertise that they build race engines does not guarantee they are doing it correctly or accurately. I have worked down to .0005” and things get real hairy in that realm. My experience is the factory usually does the best job because their machines are designed specifically to do only one job and it is very expensive if they machine a lot of parts incorrectly that will come back to haunt them with warranty repairs so they are real big on QC. The .001” PWC is a perfect example. Imagine what the results would be if they were off by .0005 which is 1/5th the thickness of a human hair and that all the way down the bore from all directions. One of my vendors runs their machines for half an hour to get it up to operating temperature to stabilize the machine before the cutter event touches the metal. There is a big difference precision machine shop and a guy with a boring bar. The iron block will hold machining accuracy better then aluminum because it is stiffer, has 1/2 the expansion rate and will heat more evenly throughout the block. So there is less to worry about. The factory shop manual is your best friend here but some of the parameters may change somewhat if your modding for more power. Do this one step at a time, post your questions and don't take any one persons word for it including mine. Cross check your answers before doing anything and you should be OK [/QUOTE]
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