Determining top dead center
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Another option is to use a '''timing tape''' as described below. | Another option is to use a '''timing tape''' as described below. | ||
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==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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*[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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==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. If the engine is assembled, use a spark plug-type piston stop tool. | 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. If the engine is assembled, use a spark plug-type piston stop tool. | ||
| − | [[File:TDC1.jpg |thumb|Strap-type and spark plug-type piston stop tools]] | + | [[File:TDC1.jpg |thumb|left|Strap-type and spark plug-type piston stop tools]] |
| + | <br style="clear: both" /> | ||
=====A word on using the damper retaining bolt to turn the engine over===== | =====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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Another risk is in stripping the threads or breaking the bolt off if you use the damper bolt to turn the engine over. If you feel resistance, or if the bolt tightens more as you attempt to turn the crankshaft- STOP! You will need to use a remote starter switch, or turn the damper by hand (plugs out), or turn the flexplate/flywheel from beneath the vehicle. | Another risk is in stripping the threads or breaking the bolt off if you use the damper bolt to turn the engine over. If you feel resistance, or if the bolt tightens more as you attempt to turn the crankshaft- STOP! You will need to use a remote starter switch, or turn the damper by hand (plugs out), or turn the flexplate/flywheel from beneath the vehicle. | ||
| − | The safest/easiest way to turn the crank is to use a tool that allows a large ratchet or breaker bar to be used. | + | The safest/easiest way to turn the crank is to use a tool that allows a large ratchet or breaker bar to be used. |
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| − | + | <gallery> | |
| + | File:Crank turning tool.jpg|Damper-mounted crank turning tool | ||
| + | File:Crank turning tool2.jpg|Crank snout-mounted crank turning tool | ||
| + | </gallery> | ||
| + | <br style="clear: both" /> | ||
==Getting started== | ==Getting started== | ||
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*[http://www.stewartcomponents.com/ Stewart Components] | *[http://www.stewartcomponents.com/ Stewart Components] | ||
*[http://www.edelbrock.com/automotive_new/mc/water_pumps/water_pumps_main.shtml Edelbrock] | *[http://www.edelbrock.com/automotive_new/mc/water_pumps/water_pumps_main.shtml Edelbrock] | ||
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==The procedure== | ==The procedure== | ||
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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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From #1 plug position on the cap, the wires will be attached clockwise around the cap following the firing order (Chevy 1,8,4,3,6,5,7,2). The rotor should be pointed to the 5:30 o'clock position to fire #1 plug. This will give maximum clearance between the vacuum canister and the runners of the intake manifold and firewall so that you have room to twist the distributor to fine-tune the ignition timing when you get the engine running. | From #1 plug position on the cap, the wires will be attached clockwise around the cap following the firing order (Chevy 1,8,4,3,6,5,7,2). The rotor should be pointed to the 5:30 o'clock position to fire #1 plug. This will give maximum clearance between the vacuum canister and the runners of the intake manifold and firewall so that you have room to twist the distributor to fine-tune the ignition timing when you get the engine running. | ||
| − | If the valve cover was removed earlier, set the valve cover on the head to keep oil from flying everywhere and start the engine and allow it to warm up | + | If the valve cover was removed earlier, set the valve cover on the head to keep oil from flying everywhere and start the engine and allow it to warm up. Do the final adjustment on the #1 cylinder rockers. |
| − | + | *Chevy: back off the rocker until it audibly clatters, then tighten it down 1/2 to 3/4 turn past where it quiets down. If you want to adjust the valves on the rest of that side of the block, now would be a good time. Replace the valve cover. | |
==Timing the engine== | ==Timing the engine== | ||
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Hook up your timing light to #1 plug wire. | Hook up your timing light to #1 plug wire. | ||
| − | Remove the vacuum advance rubber hose from the vacuum canister at the distributor and plug the end of the hose with a golf tee or other suitable plug. Adjust initial timing at the crank to what you want by rotating the distributor housing. Some use the factory setting while others prefer to set it a little more advanced for good throttle response. If using a little more initial advance at the crank, make certain you don't have so much mechanical advance in the distributor that you exceed the total timing (initial and centrifugal) specified for the engine. Most small block Chevy's will run best with around | + | Remove the vacuum advance rubber hose from the vacuum canister at the distributor and plug the end of the hose with a golf tee or other suitable plug. Adjust initial timing at the crank to what you want by rotating the distributor housing. Some use the factory setting while others prefer to set it a little more advanced for good throttle response. If using a little more initial advance at the crank, make certain you don't have so much mechanical advance in the distributor that you exceed the total timing (initial and centrifugal) specified for the engine. Most small block Chevy's will run best with around 30-34 degrees (initial and centrifugal) with fast-burn heads and 35-36 degrees with conventional heads. |
| − | If using a camshaft with more duration, you may want to increase the ignition timing lead at the crank and limit the centrifugal advance in the distributor to achieve your total ignition timing. | + | If using a camshaft with more duration, you may want to increase the ignition timing lead at the crank and limit the centrifugal advance in the distributor to achieve your total ignition timing. Some distributors, like those sold by MSD, use different bushings to control the ''amount'' of mechanical advance. The '''rate''' of mechanical advance is tailored by changing the springs and/or centrifugal weights. Usually just spring changes are all that is needed. If working on a GM HEI, the original weights are almost always a better choice than the weights sold in the various advance curve kits available from Mr. Gasket, Crane, Summit, Moroso, etc. |
| − | If you are using a radical cam and/or a converter that allows the engine to come up past where you would normally limit centrifugal advance (about 2800 rpm), you may want to alter the distributor so that centrifugal advance is locked out and put your total amount of ignition advance in at the crank. Of course, the engine will not want to crank against this much ignition lead, so you will want to install a momentary switch in the | + | If you are using a radical cam and/or a converter that allows the engine to come up past where you would normally limit centrifugal advance (about 2800 rpm), you may want to alter the distributor so that centrifugal advance is locked out and put your total amount of ignition advance in at the crank. Of course, the engine will not want to crank against this much ignition lead, so you will want to install a momentary switch in the wire going to the "+" terminal of the coil to disable the coil while you crank the engine. Once the engine is spinning, release the switch and the engine will fire normally. |
There, you're done. You should feel much better now, knowing that when you time the engine with a light, it's dead nuts on the money. | There, you're done. You should feel much better now, knowing that when you time the engine with a light, it's dead nuts on the money. | ||
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[[Category:Engine]] | [[Category:Engine]] | ||
[[Category:Good articles]] | [[Category:Good articles]] | ||
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