Determining top dead center
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[http://www.tavia.com/free_degree_wheel.html Degree wheel download] | [http://www.tavia.com/free_degree_wheel.html Degree wheel download] | ||
| − | Another option is to | + | Another option is to make a timing tape as described [[Determining top dead center#Getting started|'''below''']]. |
==Verifying top dead center at the damper line/pointer with the engine assembled== | ==Verifying top dead center at the damper line/pointer with the engine assembled== | ||
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On a street engine or a drag race engine down to 11.00 E.T. in the quarter mile, an OEM-type damper/balancer may be used legally. At 10.99 E.T., an aftermarket SFI-18.1 damper/balancer is required. | On a street engine or a drag race engine down to 11.00 E.T. in the quarter mile, an OEM-type damper/balancer may be used legally. At 10.99 E.T., an aftermarket SFI-18.1 damper/balancer is required. | ||
| − | + | ===Damper suppliers=== | |
*[http://www.damperdoctor.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=DD&Category_Code=HAR Damper Doctor] | *[http://www.damperdoctor.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=DD&Category_Code=HAR Damper Doctor] | ||
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*[http://www.mopar.com/ Mopar Performance] | *[http://www.mopar.com/ Mopar Performance] | ||
| − | + | ===Damper fasteners=== | |
*[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/ARP/?Ns=Rank%7cAsc ARP] | *[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/ARP/?Ns=Rank%7cAsc ARP] | ||
*[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/Mr-Gasket/?Ns=Rank%7cAsc Mr. Gasket] | *[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/Mr-Gasket/?Ns=Rank%7cAsc Mr. Gasket] | ||
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==Piston stop== | ==Piston stop== | ||
| − | + | If the engine is a short block on the stand, you can determine TDC with a simple homemade piston stop made from a strap of metal bolted across two head bolt holes, with the strap drilled and tapped for an adjustable bolt/nut assembly. A dial indicator can also be used on a fixture that bridges the bore or on a magnetic base. This would be an ideal time to note the piston-to-deck clearance for use in computing the static compression ratio and quench distance. | |
| − | If the engine is a short block on the stand, you can determine TDC with a simple homemade piston stop made from a strap of metal bolted across two head bolt holes, with the strap drilled and tapped for an adjustable bolt/nut assembly. A dial indicator can also be used on a fixture that bridges the bore or on a magnetic base. | + | |
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| + | If the engine is assembled, use a spark plug-type piston stop tool. | ||
| + | [[File:TDC1.jpg |thumb|left|Strap-type and spark plug-type piston stop tools]] | ||
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| + | ===A word on using the damper retaining bolt to turn the engine over=== | ||
If the damper/balancer retaining bolt is used to turn the crank over, the bolt can loosen if turned CCW. If this happens the bolt will need to be retorqued (60 ft/lbs on a SBC, 85 ft/lbs on a BBC). | If the damper/balancer retaining bolt is used to turn the crank over, the bolt can loosen if turned CCW. If this happens the bolt will need to be retorqued (60 ft/lbs on a SBC, 85 ft/lbs on a BBC). | ||
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If this is necessary (removing the water pump), this would be a good time to replace the pump if there is any question as to its condition. Pumps and gaskets are not that pricey. Whether or not you replace it, remove the pump and check for impeller slip on the pump driveshaft by holding the impeller securely with one hand and the drive hub of the pump with the other hand and twist in opposite directions. If there is any movement, replace the water pump before it fails completely. Even if the pump is good, you may want to replace it with a high-flow unit. FlowKooler, Stewart and Edelbrock are names that come to mind, there may be others who produce a quality high-flow pump. A good high-flow pump is nearly MANDATORY on a 400 SBC or any other engine which uses siamesed cylinders. | If this is necessary (removing the water pump), this would be a good time to replace the pump if there is any question as to its condition. Pumps and gaskets are not that pricey. Whether or not you replace it, remove the pump and check for impeller slip on the pump driveshaft by holding the impeller securely with one hand and the drive hub of the pump with the other hand and twist in opposite directions. If there is any movement, replace the water pump before it fails completely. Even if the pump is good, you may want to replace it with a high-flow unit. FlowKooler, Stewart and Edelbrock are names that come to mind, there may be others who produce a quality high-flow pump. A good high-flow pump is nearly MANDATORY on a 400 SBC or any other engine which uses siamesed cylinders. | ||
| − | + | ===Water pump suppliers=== | |
*[http://www.flowkooler.com/ FlowKooler] | *[http://www.flowkooler.com/ FlowKooler] | ||
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Thoroughly clean the harmonic damper and timing pointer. | Thoroughly clean the harmonic damper and timing pointer. | ||
| − | + | ===Procedure done with valves closed=== | |
Remove the valve cover for #1 cylinder and back off the rocker arms for both valves for that cylinder. COUNTING THE NUMBER OF TURNS YOU LOOSEN THE ROCKER NUTS WILL MAKE IT A SNAP TO GET NEAR TO THE CORRECT LASH WHEN YOU TIGHTEN THEM BACK AFTER THIS OPERATION. | Remove the valve cover for #1 cylinder and back off the rocker arms for both valves for that cylinder. COUNTING THE NUMBER OF TURNS YOU LOOSEN THE ROCKER NUTS WILL MAKE IT A SNAP TO GET NEAR TO THE CORRECT LASH WHEN YOU TIGHTEN THEM BACK AFTER THIS OPERATION. | ||
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At this point, we are not concerned with where the crank/piston is in the total 720 cycle of operation. In other words, we have the valves disabled, so it doesn't matter whether you are on the exhaust cycle or the compression cycle as the piston comes up to TDC. All we are working with at this point is the 360 degrees of the damper, regardless of the cam and valves. | At this point, we are not concerned with where the crank/piston is in the total 720 cycle of operation. In other words, we have the valves disabled, so it doesn't matter whether you are on the exhaust cycle or the compression cycle as the piston comes up to TDC. All we are working with at this point is the 360 degrees of the damper, regardless of the cam and valves. | ||
| − | + | ===Procedure without removing valve cover=== | |
If checking an assembled/long block engine, you will install a piston stop tool into #1 spark plug hole ([http://www.offroaders.com/tech/V8-engine-firing-order.htm domestic V8 firing orders]). Screw the top dead center housing into the spark plug hole and snug it down. Insert the probe of the tool into the tool housing and screw it in until you feel resistance of the tool probe against the piston crown. Snug it down slightly against the piston crown and start from there. | If checking an assembled/long block engine, you will install a piston stop tool into #1 spark plug hole ([http://www.offroaders.com/tech/V8-engine-firing-order.htm domestic V8 firing orders]). Screw the top dead center housing into the spark plug hole and snug it down. Insert the probe of the tool into the tool housing and screw it in until you feel resistance of the tool probe against the piston crown. Snug it down slightly against the piston crown and start from there. | ||
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There, you're done. You should feel much better now, knowing that when you set the ignition timing with a timing light, it's absolutely accurate. | There, you're done. You should feel much better now, knowing that when you set the ignition timing with a timing light, it's absolutely accurate. | ||
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| + | ==Resources== | ||
| + | ;Crankshaft Coalition Wiki articles | ||
| + | :*[http://www.crankshaftcoalition.com/wiki/Adjusting_hydraulic_lifters Adjusting hydraulic lifters] | ||
| + | :*[http://www.crankshaftcoalition.com/wiki/Valve_train_points_to_check Valve train points to check] | ||
[[Category:Engine]] | [[Category:Engine]] | ||
[[Category:Good articles]] | [[Category:Good articles]] | ||
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