[2012 Mazda Mazda2 - How to] Timing the engine, DOHC and crankshaft

This is a concise tutorial on how to time the vehicle's engine, dual overhead cams and crankshaft on a 2012 Mazda Mazda2. Due to the complexity of the procedure: Some errors and assumptions were made. I have attempted to correct them and elaborate. I will describe the procedure in better detail in the description, here. CONDITIONAL STATE: 1. Unknown engine state (pistons are not at TDC) 2. DOHCs are not installed (no chain draped over theor gears, either) 3. Crankshaft pulley (black gear with teeth) not on the engine PROCEDURAL STEPS: * Timing the engine (cylinder positioning AND crankahaft pulley placement) 1. Identify where the woodruff key / keyaway hole are (for reference) 2. Install the crankshaft pulley (remember where the woodruff key was) 3. Rotate the crankshaft until the woodruff key is at the top (away from the ground); there is a tiny metal triangle timing marker; the woodruff key should be directly under it during either: TDC or BDC 4. Use a screwdriver or long piece of metal to gently poke into the 1st cylinder (far most passenger side; nearest where you and the crankshaft are); if the metal probe barely enters and touches the piston: You *might* be on TDC! No guarantee 4a. IF the metal probe barely entered: Rotate the crankshaft so the woodruff key spins towards the rear of the vehicle (do NOT make a full revolution; very little movement should be necessary) 4b. IF the metal probe falls to the bottom of the cylinder: Great! You have found BDC and the woodruff key should be on top (nearest to the sky, under the metal marker) 5. Install the TDC adaptor tool into cylinder #1 (nearest you and the passenger side) 6. Rotate the crankshaft until it makes contact with the TDC adaptor tool (if you were at 4a: You barely rotated it and found TDC; if you were at 4b: You went from BDC to TDC) *** Your engine is now timed *** (cylinder #1 is at top dead center) * Timing the DOHC (dual overhead cams) 1. Insert the exhaust cam (nearest to the rear of the vehicle; nearest the cabin; nearest the catalytic converter) 2. Counting from left to right: Ensure the 3rd cylinder's silver tappet (valve helmet of sorts) is being pressed down (is in an OPEN state) 3. Verify that the "T" image on the gear is up right and the two horizontal lines are perfectly, horizontally lined with the top of the cylinder block 4. Insert the intake cam (nearest the front of the vehicle; nearest the radiator; nearest the air intake manifold) 5. Counting from left to right: Ensure the 4th cylinder's silver tappet is being pressed down, but the cycle is just near the end and the next cycle is about to begin (manually rotate the camshaft and imagine that YOU are the engine) 6. Verify that the deep grooves on the cam a perfectly horizontally aligned with the cylinder block and the "VTV" text imprinted is on the TOP (nearest the sky; furthest from earth; closest to your car's roof) *** Your DOHC is now timed *** (They are both lagged by 1 cycle and then are synchronized to be 1 cycle apart from each other) You have successfully timed your 2012 Mazda Mazda2's crankshaft pulley (10th tooth from the gap should be touching the sensor), the engine (cylinders #1 and #4 should both be at TDC while cylinders #2 and #3 should both be at BDC) and the DOHCs (the exhaust should barely cycle just behind the cylinder, but one cylinder behind the intake AND the intake should almost be finished with a cylinder before the next cylinder's spark is ignited (from "cylinder #4" to "cylinder #2"). Cylinder firing order: 2-1-3-4 Why would the intake cam be leaving a TDC? Because it's on it's way down and has no air, no fuel and no reason to have a spark; the 2nd cylinder is traveling from BDC to TDC and is full of air, will have fuel soon and a spark upon reach TDC (which is approximately when the DOHC spins to actuate the valves that then open and close to allow gases to move in and out). NOTE: I will be uploading a replacement video later this year along with 129 other meticulous videos. Happy 2024!!! :)

Added 1 Jun 2026