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techtalk:evo:engmech04a [2019/02/12 17:38] hippysmack [About Relieving Valve Pressure] |
techtalk:evo:engmech04a [2019/02/17 15:39] hippysmack [About Relieving Valve Pressure] |
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| ====== Before Removing Lower Cover ====== | ====== Before Removing Lower Cover ====== | ||
| ===== About Relieving Valve Pressure ===== | ===== About Relieving Valve Pressure ===== | ||
| + | See also [[techtalk:ref:svcproc16#hydraulic_lifter_-_disassembly_inspection_assembly|Hydraulic lifter disassembly - inspection - assembly]] in the REF section of the Sportsterpedia. \\ | ||
| + | |||
| (also known as "Bleeding the Lifters") \\ | (also known as "Bleeding the Lifters") \\ | ||
| You are not actually doing anything but allowing the oil time to leave the lifter body out of the holes in the each lifter before removing the lower rocker mounting bolts. \\ | You are not actually doing anything but allowing the oil time to leave the lifter body out of the holes in the each lifter before removing the lower rocker mounting bolts. \\ | ||
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| This could cause the camshafts to crook sideways and gouge the bushings. \\ | This could cause the camshafts to crook sideways and gouge the bushings. \\ | ||
| - | **The 04-Up FSMs changed the sequence of removing the bolts**. \\ | + | **They 04-Up FSMs still state to rotate the crankshaft so both valves are closed on the head being repaired**. \\ |
| + | **But they changed the sequence of removing the bolts**. \\ | ||
| Removing them in the proper order also prevents potentially warpage of the cover(s). ((Screw Loose Dan of the XLFORUM http://xlforum.net/forums/showthread.php?t=1488750)) \\ | Removing them in the proper order also prevents potentially warpage of the cover(s). ((Screw Loose Dan of the XLFORUM http://xlforum.net/forums/showthread.php?t=1488750)) \\ | ||
| It also mentions making sure that both valves are closed prior to removal for each cylinder (separately) of the rocker box you're removing. \\ | It also mentions making sure that both valves are closed prior to removal for each cylinder (separately) of the rocker box you're removing. \\ | ||
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| It may take longer if it's particularly cold or if you're using heavy oil. \\ | It may take longer if it's particularly cold or if you're using heavy oil. \\ | ||
| But if you're sitting at overlap TDC, you may never see the valves close because the lifter will shorten as far as it goes and still be too long. \\ | But if you're sitting at overlap TDC, you may never see the valves close because the lifter will shorten as far as it goes and still be too long. \\ | ||
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| - | You should never turn over the motor or attempt to start it until bleed down is complete. \\ | ||
| - | Doing so can easily cause valve-to-valve and/or valve-to-piston contact, causing valves to bend. \\ | ||
| - | Even installing the rocker box with the motor not positioned properly puts the valves at risk. \\ | ||
| - | If one or both valves is held off it's seat due to the lifter not fully bleeding down, and you try to start the motor, and by some miracle you don't bend a valve, that cylinder won't run anyway, because it'll have no compression. \\ | ||
| **There are two TDC's for EACH cylinder**. ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=1874585)) \\ | **There are two TDC's for EACH cylinder**. ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=1874585)) \\ | ||
