PERFECT TIMING?
Q
I recently bought a Ford Cortina with a Pinto 1300cc engine. I discovered the ignition timing was ludicrously over-advanced, so I set it to the correct figure. After this, the engine was sluggish and full of flat spots and hesitations. I set it back to its original position, though I’m sure this is wrong. What’s the matter with it?
Ken Graves, Buxton
Theo says: A
We think the valve timing has been upset. This is remarkably common on OHC engines if the belt or chain has been removed and replaced. Your Pinto engine has a disc behind the camshaft sprocket with a pointer on it. This should point to a dot on the cylinderhead at 6 o’clock when the crankshaft is set to its pulley TDC mark. Note the cam mark will only align once every two revolutions of the crank, as it turns at half crank speed.
If it doesn’t line up, detension the belt, slip it off the cam sprocket and realign the cam timing marks, keeping the crankshaft-distributor drivecamshaft run of belt taut. Then retension the belt.
A complication is that the distributor drive sprocket may be disturbed during this operation. The rotor arm should point to the cylinder 1 segment of the distributor cap and the points should be just slightly open when the cam and crank marks are both in correct alignment. It may be necessary to rotate the distributor and/or reposition the distributor drive sprocket to achieve this.
Afterwards, turn the crank pulley back, then forwards to meet the ignition timing mark and set the distributor so the points are just opening at this point. If you turn on the ignition and swivel the distributor a little back and forth, you’ll hear the click of a spark being formed. Finally – and whenever a timing belt or chain has been disturbed rotate the engine by hand for two full revolutions to make sure there is no valve-piston contact. If there is, wind it back to the starting position and recheck the marks. If the marks align, make sure the crank and cam sprockets have not somehow rotated on their shafts, for instance due to a missing or damaged Woodruff key or keyway.