Replacing Chrysler 2.2 and 2.5 liter engine timing belts
by Bob O'Neill
The timing belt is driven by the crankshaft, and turns the cam and the intermediate shaft; indirectly, it drives the distributor.
Sprockets on the cam and intermediate shaft are twice the diameter of the sprocket on the crank, so for every two turns of the crankshaft the cam and intermediate shaft is turned one time. The intermediate shaft is geared to mesh with the driver gear of the oil pump; the slot in the oil pump gear drives the distributor, as the tabs on the distributor fit into the oil pump drive gear slot. The distributor is therefore driven in part by the intermediate shaft. For each turn of the cam and intermediate shaft, the distributor shaft turns one time.
The timing belt should be replaced at 60,000 mile intervals (on some cars, up to 105,000 miles is recommended, but this may be imprudent).
If, after 60,000 miles, an inspection of the timing belt indicates little wear, it could be used but should be checked at every oil change after the 60,000 mile interval. However, because the procedure to replace it is easy and because these belts are not expensive, the belt should be replaced at the 60,000 interval.
These engines are non-interfering which means that should the belt snap while the engine is running the valves will not contact the pistons. But to prevent being stranded while driving, replace the belt every 60,000 miles. While you're at it, replace the other drive belts too. (Editor's note: the process for the dual-overhead-cam engines known as the "Turbo III" is somewhat different and more difficult. These engines are fairly rare and were only installed in the Daytona R/T, Spirit R/T, and certain cars in Mexico.)
- You will need to remove some pulleys and the A/C compressor/alternator bracket. Jack up the right side of the car to remove weight from the wheel. Be sure to support the car with a jack stand to safely support the car.
- Remove the wheel and the inner plastic fender shroud to expose the crankshaft pulley. Then loosen the bolts on the crankshaft pulley and the water pump pulley so they will be easier to remove once the belts are removed. This is done to gain access to the timing belt sprockets.
- Remove the tension from the accessory drive belts (power steering pump, A/C compressor, and alternator), then remove the belts. If they are to also be replaced, discard them.
- Remove the bolts which hold the crankshaft and water pump pulleys as well as the pulleys.
- The timing belt cover should be removed next. To remove the top part of the timing cover remove the nuts on the studs at the timing belt side of the valve cover. There is one in front and one in back. Then there is one screw where the top and bottom parts of the timing belt cover come together. Remove this screw to remove the upper timing belt cover. There are two 10mm bolts which hold the bottom cover in place. Remove these bolts and remove the lower timing belt cover.
- Next the engine should be supported. Place a jack under the passenger side of the engine to support it. It will only need to be lowered a very small amount. To protect the oil pan by spreading the force, place a moderately thick piece of wood between the oil pan and the jack. To maintain engine centering, be very careful not to move the engine other than down and then only a small amount. Once the upper mount cross bolt is removed, remove the large nut below the bracket. It is important that the engine not be moved until it is raised once the mount bolts have been reinstalled.
- Because the timing belt is routed so it fits behind the A/C compressor bracket, this bracket must be removed. So remove the compressor (4 bolts) and carefully support it aside without putting pressure on the hoses. Then remove the bracket. There are bolts on the side (front or belt side) of the engine as well as some on the side (distributor side of the engine).
The A/C belt tension pulley will also be removed and behind the two bolts which attach the bracket to the belt side of the engine there is a 'dog bone' spacer which may fall. Be aware of this.
- With the A/C compressor removed it is necessary to remove the upper engine mount. There is a cross bolt and a large nut under the support bracket for the mount. Removing these will allow the bracket to be removed which impedes the removal and installation of the timing belt.
- The old timing belt if still in place is tensioned by the timing belt tensioner. This is a pulley which is mounted by a bolt which is off center of the pulley bearing mount. It is attached to the block with a bolt. Loosen this bolt and slide the tensioner around to allow the timing belt to be removed. If the tensioner is being replaced (some recommend this at least ever 100,000 miles), remove the tensioner to be replaced with the new one.
- Remove the belt from the pulleys and slide it through the gap made by removing the engine mount bracket.
- Install the new belt by sliding it through the gap made by removing the engine mount bracket and mount it on the cam sprocket to keep it out of the way.
- Reinstall the engine mount bracket and tighten all bolts on the mount bracket. The large nut is tightened to 75 ft-lb (102 n-m).
- Now it's necessary to properly position the timing belt sprockets to 'time' the cam. The first step is to align the crankshaft sprocket mark with the mark on the intermediate shaft sprocket. To insure that these marks are perfectly aligned use a straight edge and position it so it intersects the centerline of the center bolts (Fig #1)
- Then with the straight edge in place position the marks on the sprockets so they face one another and are in line with the straight edge. This step will 'usually' work because when the mark on the intermediate shaft sprocket and the mark on the crankshaft sprocket are properly positioned it should result in the position of the distributor where the rotor is pointing at the #1 spark plug wire. However to be sure that this happens you could remove the distributor and be sure the slot is horizontal to the centerline of the engine where the center line is parallel with the crankshaft.
Fig #1(notice that in the illustration the marks are not exactly lined up)
- With the lower two sprockets lined up it's time to line up the cam sprocket. Once again use a straight edge to position the cam sprocket so the index (small) hole is positioned up and away from the crankshaft but in line with the centerline of the crankshaft and cam shaft bolts. The two larger holes at 90 degrees on either side of the index hole should be positioned so the mating surface of the front journal cap (cam journal) intersects these holes. (See Fig #2)
- With the sprockets positioned properly slide the timing belt in place and install a new tensioner or turn the tensioner tension the belt. To do this properly there is a special tool which when positioned on the tensioner applies weight to the concentric bearing in a counter clockwise direction. Proper tension is indicated when the tool is within 15 degrees of horizontal. (See Fig#3) While the tool is attached and the bolt is loosened slightly turn the engine over by hand twice to take up any slack in the belt. Once this is done check the positioning of the sprockets to be sure they have not shifted and to insure that the belt is still positioned properly.
- Tighten the tensioner attachment bolt to 45 ft-lbs (68 N-m) once you have insured sprocket alignment and the belt tension is correct using the special tool. There have been reports that the proper tension is also indicated when the tensioner is positioned so the longest length of the belt (between the intermediate shaft sprocket and cam sprocket) can be twisted ½ turn easily. It is important that the belt is not too tight as this will cause excessive and premature wear resulting in belt failure. If the belt is too loose it could result in the belt skipping one or more teeth resulting be incorrect cam timing.
(note the tool on the left and a 15mm wrench
to tighten the attaching bolt on the right)
Set the Base Ignition Timing
- Install the A/C bracket keeping in mind the dog bone spacer and A/C compressor belt tensioner pulley. Tighten all bolts to proper torque. Install the A/C compressor and using the 4 nuts/bolts and tighten properly.
- Install lower timing belt cover and install the two 10mm bolts.
- Install the crankshaft belt pulley and the water pump pulley and tighten the bolts properly.
- Install the inner plastic fender shroud.
- Remove the engine support (jack) and reinstall the wheel on the passenger side.
- Lower the car to the ground.
- Install the belts and tension them properly.
- Install the upper timing belt shroud and using the screw which holds the upper to lower tighten it properly.
- Install the nuts on the studs at the valve cover to hold down the upper timing belt cover.
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- With the transmission in neutral and all accessories turned off. Connect a timing light to the #1 spark plug wire.
- Start the engine and allow it to reach normal operating temperature.
- Turn off the engine and loosen the distributor hold down bracket bolt. Not too loose as you only need to turn the distributor.
- Remove the connector to the coolant sensor and start the engine.
- Using the timing light set the distributor so the timing mark is at 12 degrees BTDC.
- Tighten the hold down bracket bolt for the distributor and recheck the ignition timing. Adjust as necessary.
- Turn off the engine and reconnect the coolant temperature sensor, disconnect the timing light.
- Disconnect the battery to clear computer fault codes.
- Restart the engine to check for proper operation.
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