If it's a diesel NO, Petrol Sometimes.
The 1999 Ford Ranger 3.0L V6 engine has a no-interference design. This means that?æ there is enough clearance between the piston and the valves. Therefore, when the timing belt fails, no damage will occur to the engine.
bumping clearance is the clearance between piston and head ,piston and crank endside
most auto mechanic preferred .002 clearance from piston skirt to sleeve
Push in the piston on the caliper with your hand or a vice grips to get more clearance.
Piston ring gap.
Well...... you need A LITTLE bit of clearance for the gas mixture to lubricate the piston and cylinder. Plus your piston expands when it gets hot.
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In an engine, the piston's go up and the valve's that are adjacent to that piston go up. When the piston goes down the adjacent valves go down. This is achieved by the timing belt or chain and the engine timing being set correctly. If the belt or chain breaks, the pistons still go up and down, but the valve's stop moving. On a non clearance engine, the piston will go up and hit the valves, resulting in bent valves and a now needed head job. In a clearance engine, the top of the piston has an inset cut into it that is just enough room to avoid hitting the valves.
Piston is the device with a cup like shape that fit completely in the Cylinder.
The volume between the engine head and piston when the piston is in the head dead center piston R - is expressed in cubic inches
oil
0.003" ~ 0.004"