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Harmonic balancer/damper - How to remove and install
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=Overview= The harmonic balancer or damper is usually a tight press-fit onto the end of the crankshaft. This is so the torsional vibrations of the crankshaft generated by the power pulses of the engine can be transmitted to- and absorbed or dissipated by- the harmonic balancer. If the fit isn't tight, the harmonic balancer will not be able to absorb the vibrations and in some cases this can lead to a failure of the key/keyway that locates the balancer and/or the fastener that secures it to the crankshaft along with the tight press-fit. =Tools= It is always advisable to use a dedicated tool for damper removal. To do otherwise risks damaging the damper beyond repair, damaging the crankshaft or other related parts and covers, or personal injury. Because of how tightly most dampers are pressed onto the crank, there's basically no way a damper could be pried off anyway. Heat cannot be used because there could be damage to the damper oil seal. Also most dampers have an elastomeric band that separated the inner hub from the outer inertia ring. Heat can ruin the bond between the two, causing catastrophic failure of the damper that could damage the radiator, water pump, front mounted accessories, the hood, could possibly sever engine oil or ATF cooler lines, radiator hoses, etc. While there are cheap pullers available that are usually good for a couple uses before it strips out or bends, unless this is a one-time repair and it's not anticipated to ever be done a second time it's always a good idea to invest in a quality tool that's made to last. [[File:SUM-G1025 damper puller-installer.jpg|frame|left|Summit p/n G1025 damper puller/installer tool]][[File:Cheap damper puller.jpg|frame|right|250px|Cheap puller]][[File:Damper installer tool.jpg|frame|left|300px|Damper installer tool, metric and inch crank threads]] <br style="clear:both"/> =Procedures= ==Removal== The pulley and anything else in the way is first removed so the damper can be accessed. The puller is installed using the same thread bolts that secured the bottom pulley. The procedure shown is for most engines up until the LS-series Chevy and the Gen 3 Hemi, etc. Start out with the puller center screw lubricated well. The crank will have a recess for the puller shaft nose to index on. [[File:Balancer puller installed.jpg]] On the Chevy V8 the bottom pulley bolt thread size is 3/8-24. Most engines will be either 5/16-18 or 5/16-24 or 3/8-16 or 3/8-24. You won't be able to use the original pulley bolts; most puller sets come with an assortment of bolts, otherwise find three that are the same length and long enough to use the puller. Take the bolts down evenly so the puller is centered on the snout then use a breaker bar to tighten the puller. The crank may try to turn once the puller is tight; you can run a prybar through the puller bolts to hold the engine from turning, or get a helper under the vehicle to hold the flexplate or flywheel. If it's a manual trans you can put it in gear and set the parking brake and block the wheels to keep the engine from turning over. Don't be tempted to use an impact wrench on the puller. This will damage the threads if over done. Keep turning the center screw of the puller until you feel/see the damper start to back off the crank. Once it starts, most of the time it will come off the rest of the way easily. Don't let the damper drop onto the floor. Once the damper is off, remove the puller bolts and store the tool away for the next time. If the damper is to be reused, clean it off first, coat the snout inside and out with motor oil and store away from rain, etc. ==Installation== ===With threaded damper bolt hole in crank=== ===Without threaded damper bolt hole in crank=== Some SBC engines from 1968 +/- a couple years came with the damper installed at the factory (by what means hasn't been determined, but likely a hydraulic press of some sort), but with no drilled and tapped hole in the crankshaft snout for a retainer bolt. Removal isn't affected by this; installation IS. ====Drilling the snout==== The ideal solution is to drill and tap the snout with 7/16-20 threads. This must be done correctly, with the hole drilled and tapped concentric to the crank c/l. If there's any question about this, let a machine shop handle the job. ====Hardware==== Many recommend using an ARP damper bolt and washer. Torque it to their specs, or to 60 ft/lbs if using an OEM bolt/washer with clean oiled threads. If there is access to good quality grade 8 hardware, a 7/16-20 x 2.25" long bolt with a 1/4" thick washer can be used. ====Proceed without drilling the snout==== If drilling/tapping the snout isn't possible, the hobbyist engine builder can install the damper using a block of wood and a heavy hammer or short sledge. This operation requires eye protection There are a couple things that will help ease the job. *The damper is held on by a 0.0007"-0.0014" press fit. Heating the damper in 200ยบ F hot water for 10 minutes will cause it to expand a bit. Also chilling the crank snout with a bag of ice will shrink it a bit. Between the two, the difference can be enough to really ease the installation. Avoid using a torch on the damper hub. The chance of overheating it is too great to risk damaging or outright ruining the damper in the opinion of some. *Use a sturdy block of wood like a 4-5" thick slice of a wooden fence post or 4x4, use it grain-on, not across grain to help keep it from splitting- you'll be hitting it fairly hard in most cases, especially if no heat/cold is used. The wood is used to insulate the damper inner hub from the hammer blows. {{warning|NEVER hit the damper on the outer ring- this can break the bond between the rubber and steel, making the damper useless. NEVER hit the damper metal to metal with a hammer. A damaged damper could fail, possibly causing personal injury and damage to the vehicle or even bystanders. Use gloves and '''[[Health and safety in the shop or garage#Eye protection|eye protection]]''' at a minimum.}} {{Youcanedit}} [[Category:Engine]] [[Category:Undeveloped articles]] <br><br><br><br>
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