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| Make sure you remove all the bolts securing the intake manifold manifold to the block. If you get any resistance – STOP – find out what is restraining the manifold before proceeding. |
Finding TDC #1 Firing Stroke
Note: The following procedures assume you are aware of and will follow the basic safety precautions of working on a car. If not, do not read any further and go to another exciting OvalTracking.com article.
Get your shop area clean and your vehicle in position to raise it. We’re going to use the engine to help us find TDC of #1 on its firing stroke. Remove the ignition coil wire from the distributor cap and connect it to something metal to ground it so the engine will not start. Next, remove the #1 spark plug, and as many as you can reach easily – you can leave them hooked up to their wires – make sure you tag which wires go to which cylinders. The more plugs removed the easier it is to turn over the engine. Also gives you an excuse to check the condition of the spark plugs.
If the car has a manual transmission, make sure it is in Neutral and the car wheels are chocked. If the car has an automatic, also put it in Neutral. Put your thumb over the open sparkplug hole of #1 cylinder. Have a buddy crank the engine over until you feel air pressure. This means the #1 piston is on the compression stroke and coming up to TDC/firing.
Next, manually turn the crankshaft nut a little in the same direction of engine rotation (clockwise looking at the engine) until the TDC marks of the harmonic balancer and timing chain cover are directly aligned.
You may have to do this whole procedure a couple of times to make sure you are on the compression stroke coming up to TDC/firing – be patient and get this right.
Now the #1 piston is at TDC/firing and the camshaft and crankshaft are synchronized. If the engine timing marks are on a separate pointer or tab, make sure you mark the tab’s location on the cover or block – so that if you have to remove it, you can make sure it is mounted at the correct location for TDC/firing. The next step is to start removing parts to get to the camshaft. Begin by disconnecting the battery and make sure the (+) and (-) leads are clear of the terminals. You don’t want any stray electrical surprises.
Removing parts and accessories to finally expose the timing chain will vary by vehicle, but we’ll follow the basics here on our carbureted small-block Chevy 350.
Raise and safely support the car about 12-inches high because you’ll be working under it. You’re going to need a couple of special tools like a harmonic balancer puller/installer, and supplies like a new gasket set, hi-temp silicone gasket sealer, crankshaft damper bolt, new engine coolant, two (2) changes of new conventional engine oil – not synthetic – and 2 oil filters, and hi-grade thread locking compound.
Distributor
Because the distributor gear meshes with a drive gear on the rear end of camshaft on a Chevy, you have to remove the distributor to remove the cam. Now that the engine is at TDC #1 on its firing stroke, and you remembered to label which wire went to which cylinder, you can take off the distributor cap with the wires attached. Next, make two marks with a permanent marker: one noting where the distributor rotor is pointing to on the distributor housing, and another on the intake manifold directly below the housing’s mark – this orients the housing to the manifold. At re-assembly, you’ll line up these marks on the distributor rotor and housing so the engine will be near correct engine ignition timing for start-up. Remove the hold down clamp and lift out the distributor.