Initial Startup

 

Initial Startup

 

 

So you’ve just rebuilt your engine, installed a new crate motor, or maybe only replaced the cam. Now what do you do to prepare the carb and ignition for the first fire up so that you won’t be cranking the engine excessively and causing undue wear? If a new flat tappet (non roller) cam is involved, it’s even more important in order to prevent cam failure. Ensure everything is lubed properly (with black moly paste on new cam lobes and bottoms of lifters), oil system primed, clearances checked, bolts torqued, hoses and fittings tight, fluids and filters in place, valves properly adjusted, and battery charged, etc. Valve/rocker adjustment was covered in a previous issue. It’s highly recommended to add a bottle of GM EOS assembly lube to the oil on new or rebuilt engines and with new cams. First, DO NOT make any changes or repairs to the carb or ignition system unless absolutely necessary. This just adds another thing that can go wrong and prolong the cranking. It’s very helpful to put the engine at the no.1 firing position at TDC (the zero mark) and mark the position of the distributor rotor blade and position of the dist base before disassembling the engine. Be sure it’s at the no.1 position instead of no.6 by checking to see if both valves are closed on no.1 cyl (they will be partially open on no.6). The following is very important to prevent excess cranking: Fill the primary float bowl in the carb with gas. Make a small funnel out of paper and Scotch tape that will fit in the bowl vent tube and pour about 3 ounces of gas in through the vent. Open the throttle a few times til you see or hear the accelerator pump squirting gas.  Bring the engine to the no.1 firing position (both no.1 valves closed) at the zero mark on the timing tab. Install the distributor with the rotor blade and housing in the same position as marked before removal. You will probably have to rotate the oil pump driveshaft to get the dist to seat by turning it with a long screw driver or oil pump priming tool. Attach a timing light so it’s ready to go as soon as the engine fires. Disconnect and plug the vacuum advance line until after timing is set. If you didn’t mark the dist position or are installing a new engine, etc., put the engine at the no.1 firing position at the zero mark. Install the distributor so the rotor blade is pointing to where you want the no.1 plug wire to be on the dist cap. Mark the location of the no.1 plug wire terminal of the cap on the dist housing by temporarily placing the cap on the housing and marking the housing below the cap. Now rotate the crank (by hand with all sparkplugs removed) to the proper initial advance position on the timing tab (example: 8 deg BTDC). Rotate the dist housing so the mark lines up with the rotor blade and lock it down. This will put timing close enough to fire but will still need adjusting. Make sure the remaining plug wires are in the proper position on the dist cap and plugs by following the firing order (18436572-Chevy) clockwise around the cap.  Install the plugs and you should now be ready to light a fire in it. Adjust timing right away and if it’s a new non-roller cam run the engine at a minimum of 2000 rpm for at least 20 minutes for proper cam break-in. Keep an eye on the oil pressure and temp gauges and have someone watch for leaks. If air temp is warm it helps to place a large fan in front of the radiator to aid cooling.