Determining top dead center
(→The procedure) |
|||
| Line 10: | Line 10: | ||
[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 use a '''timing tape''' as described below. | + | Another option is to use 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== | ||
| Line 26: | Line 26: | ||
There are a multitude of different dampers and timing pointer locations on a small block Chevy. Refer to [[Timing Tabs and Damper TDC Lines SBC]] for more on them. Other engines can refer to a service manual. | There are a multitude of different dampers and timing pointer locations on a small block Chevy. Refer to [[Timing Tabs and Damper TDC Lines SBC]] for more on them. Other engines can refer to a service manual. | ||
| − | The whole reason for doing this operation in the first place is to be able to time the engine with a timing light and know | + | The whole reason for doing this operation in the first place is to be able to time the engine with a timing light and know '''''absolutely''''' that the timing is correct. The elastomeric material that connects the outer inertia ring of the harmonic damper/balancer to the inner hub of the damper/balancer which presses onto the snout of the crankshaft begins to break down over time due to ozone in the atmosphere and oil and fuel or other foreign materials which may find their way onto the material. |
When this happens, the outer ring may slip circumferentially in relation to the inner hub, rendering any attempt to time the engine with a timing light futile. Even though this operation you are about to do will bring the timing marks back to correct for the time being, there is no guarantee that the ring will not slip further after a while. You also have no idea if the timing pointer matched the inertia ring in the first place if the engine has been disassembled and reassembled by someone else in its lifetime. If you want to bulletproof the operation, then start with a new or rebuilt damper and use the correct timing pointer for that damper. | When this happens, the outer ring may slip circumferentially in relation to the inner hub, rendering any attempt to time the engine with a timing light futile. Even though this operation you are about to do will bring the timing marks back to correct for the time being, there is no guarantee that the ring will not slip further after a while. You also have no idea if the timing pointer matched the inertia ring in the first place if the engine has been disassembled and reassembled by someone else in its lifetime. If you want to bulletproof the operation, then start with a new or rebuilt damper and use the correct timing pointer for that damper. | ||
| Line 39: | Line 39: | ||
*[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] | ||
| + | *[http://www.atiracing.com/products/dampers/index.htm ATI] | ||
| + | *[http://www.fluidampr.com/ Fluidamper] | ||
| + | *[http://www.jegs.com/i/JEGS/555/51600/10002/-1 Jegs] | ||
| + | *[http://www.summitracing.com/search/Brand/TCI-Auto/Product-Line/TCI-Rattler-Torsional-Vibration-Absorbers/ Tci Rattler] | ||
| + | *[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/Summit-Racing/?Ns=Rank%7cAsc Summit Racing] | ||
| + | *[http://www.summitracing.com/search/Department/Engines-Components/Section/Harmonic-Balancers/Brand/Pioneer-Automotive/?Ns=Rank%7cAsc Pioneer Automotive] | ||
| + | *[http://www.proformparts.com/category-exec/category_id/260/nm/Harmonic_Balancers_Covers Proform Parts] | ||
| + | *[http://www.scatcrankshafts.com/ Scat Crankshafts] | ||
| + | *[http://www.trickflow.com/egnsearch.asp?N=400098+4294925232+115+4294839044 Trick Flow Specialties] | ||
| + | *[http://www.dormanproducts.com/default.aspx Dorman] | ||
| + | *[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/Mr-Gasket/?Ns=Rank%7cAsc Mr. Gasket] | ||
==Piston stop== | ==Piston stop== | ||
| Line 107: | Line 121: | ||
Replace the spark plugs and wires. Remove the masking tape, reinstall water pump, pulley, fan, shroud and belts if they were removed previously. Replace any coolant/water you may have lost in the operation. | Replace the spark plugs and wires. Remove the masking tape, reinstall water pump, pulley, fan, shroud and belts if they were removed previously. Replace any coolant/water you may have lost in the operation. | ||
| − | Remove the cap from the distributor and align the rotor with the cap terminal that coincides with #1 plug by rotating the distributor housing. Looking down on the motor from a birds-eye view, the rotor needs to be pointing toward 5:30 on an analog clock face (pointed toward #1 cylinder). The gears that drive the distributor off the camshaft are helical, so you need to drop the distributor into place so that it can spiral down and be in the correct position when the distributor housing is seated on the intake manifold. On a Chevy, clockwise rotation of the housing retards the ignition timing, counter-clockwise advances it. | + | Remove the cap from the distributor and align the rotor with the cap terminal that coincides with #1 plug by rotating the distributor housing. Looking down on the motor from a birds-eye view, the rotor needs to be pointing toward 5:30 on an analog clock face (pointed toward #1 cylinder). The gears that drive the distributor off the camshaft are helical, so you need to drop the distributor into place so that it can spiral down and be in the correct position when the distributor housing is seated on the intake manifold. On a Chevy, clockwise rotation of the housing retards the ignition timing, counter-clockwise advances it. |
| − | From #1 plug position on the cap, the wires will be attached clockwise around the cap following the firing order (Chevy 1 | + | On a Chevy V8, because of the pitch of the helical gears on the cam and distributor, the rotor will turn about 2 inches CW as the distributor is lowered into position. That means the rotor needs to start out about 2 inches CCW from where it needs to end up with the distributor fully seated. |
| + | |||
| + | From #1 plug position on the cap, the wires will be attached clockwise around the cap following the [http://www.crankshaftcoalition.com/wiki/Category:Firing_orders firing order] (Chevy V8: 1-8-4-3-6-5-7-2). As was stated in the last paragraph, 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. Do the final adjustment on the #1 cylinder rockers. | 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. | ||
| Line 124: | Line 140: | ||
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. | 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 | + | 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. |
[[Category:Engine]] | [[Category:Engine]] | ||
[[Category:Good articles]] | [[Category:Good articles]] | ||
Your Privacy Choices