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Showing results for tags '4.2l timing'.
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For finding TDC on the compression stroke without the starter functioning, a time-honored approach is a whistle that fits into the spark plug hole for #1 piston. Spark plugs removed to ease crankshaft rotation, this device allows rotating the crankshaft by hand in the normal direction of rotation while listening for the whistle as the piston rises on the compression stroke. Note: If you have brazing or soldering equipment, you can make this tool using an old spark plug shell with the porcelain, electrode and ground strap removed. Braze or solder a metal whistle to the metal plug shell. Remove any burrs or debris from the "tool", then thread it into the spark plug hole for #1 plug in this case. For a pre-made type, here's a popular and inexpensive example that uses a rubber stopper instead of a threaded base. You'll get the idea: https://www.amazon.com/Innovative-Products-7894-Flexible-Compression/dp/B000TQ16HG. An alternative is to use a compression gauge installed in #1 cylinder spark plug hole. Plugs removed, rotate the crankshaft and watch for the bump in compression as the piston rises on the #1 compression stroke. Simultaneously watch the crankshaft damper timing mark to make sure you're rising to #1 TDC. Once the piston is at TDC (look down the #1 spark plug opening and confirm that the piston is at its peak with the TDC mark aligned on the crank pulley/damper), you can decide where you want to place the #1 spark plug wire in the cap rotation. Allow enough room for the distributor's vacuum canister to rotate back and forth without interference when you set the spark timing. Lift the distributor away from the camshaft drive to align the distributor shaft and rotor with a selected distributor cap position for the #1 spark lead. Then you can hook up the remaining spark leads in clockwise rotation, following the firing order: 1-5-3-6-2-4. There is a preferred position for #1 wire in the cap, traditionally around the 5:30 to 6-o'clock position on a CJ Jeep inline six. Without EFI and using a conventional HEI/DUI distributor like you're doing, you can select whatever cap position you want for #1 wire lead. Just make sure the rotor points to that position at TDC for #1 piston on the compression stroke. Allow enough room for distributor movement to fine tune the spark timing. Install spark leads following the 1-5-3-6-2-4 Jeep inline six firing order. Moses
