Timing chains, tensioners and sprockets — removal, inspection and installation Ford F150
Caution: These engines are difficult to work on and require special tools. On any procedure involving timing chain, camshaft(s) or cylinder head removal, the steps must be read carefully and disassembly must proceed using the special tools, otherwise damage to the engine could result.
Caution: The timing system is complex. Severe engine damage will occur if you make any mistakes. Do not attempt this procedure unless you are highly experienced with this type of repair. If you are at all unsure of your abilities, consult an expert. Double-check all your work and be sure everything is correct before you attempt to start the engine.
Caution: Because this is an interference engine design; if one of the chains has broken, there will be damage to the valves (and possibly the pistons), and removal of the cylinder head(s) will be required.
Note: A special crankshaft holding/rotating tool (Rotunda part no. 303-448) is required for this procedure.
Note: If you are removing the left-side timing chain (for access to the left cylinder head, for example), the right-side timing chain must be removed first.
Removal
1. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
2. Remove the spark plugs (see Tune-up and routine maintenance) and position the number one cylinder on TDC (see Top Dead Center (TDC) for number one piston – locating).
3. Remove the valve covers (see Valve covers – removal and installation) and the timing chain cover (see Timing chain cover – removal and installation). Two long timing chains connect the crankshaft to the camshafts.
i.4 Use the special tool (303-448) to rotate the crankshaft
4. Starting with the right (passenger’s side) primary chain, use the special tool (303-448) to rotate the crankshaft during this procedure (see illustration). Slide the tool over the end of the crankshaft snout, then rotate the crankshaft until the keyway on the crankshaft is at the 7:30 position.
Caution: Check the right-side VCT unit (timing chain sprocket) on the exhaust camshaft; the RH mark must be at the top. If it is not, rotate the crankshaft one complete revolution and return the keyway to the 7:30 position.
5. Push in on the right (paassenger’s side) primary chain tensioner arm to compress the plunger in the tensioner. Keep it depressed until you can insert a paper clip or drill bit into the hole in the tensioner to keep it retracted.
6. Turn the crankshaft just a little, if necessary, to provide some slack in the timing chain.
7. Remove the right-side tensioner, then the tensioner arm and the stationary chain guide bolt and guide.
8. Remove the right-side primary timing chain.
Caution: If it was turned slightly, return the crankshaft keyway back to the 7:30 position.
9. Remove the three bolts securing each VCT (sprocket) assembly to the right-side intake and exhaust camshafts.
Caution: Don’t allow the shafts to turn as this is done. Place a large wrench on the flats of the camshaft while using a ratchet and socket to remove the VCT assembly mounting bolts.
10. Slide the VCT units forward 5/64-inch (2 mm).
11. Push down on the right-side secondary chain tensioner while twisting the plastic guide on the top of the tensioner until it is positioned 90-degrees to the timing chain. The VCT assemblies and secondary chain can now be removed.
Caution: Don’t mix up the VCT units; they are not interchangeable.
12. Using special tool 303-448, rotate the crankshaft clockwise 360 degrees (one complete revolution). Continue to turn the crankshaft until the keyway is in the 3:30 position.
13. Push in on the left (driver’s side) primary chain tensioner arm to compress the plunger in the tensioner. Keep it depressed until you can insert a large paper clip or drill bit in the hole in the tensioner.
14. Turn the crankshaft just a little, if necessary, to provide some slack in the timing chain. Remove the left-side tensioner, then the tensioner arm and the stationary chain guide bolt and guide. Remove the left-side primary timing chain.
Caution: If it was turned slightly, return the crankshaft keyway back to the 3:30 position.
15. Remove the three bolts securing each VCT (sprocket) assembly to the left-side intake and exhaust camshafts.
Caution: Don’t allow the shafts to turn as this is done. Place a large wrench on the flats of the camshaft while using a ratchet and socket to remove the VCT assembly mounting bolts.
16. Slide the VCT units forward 5/64-
inch (2 mm). Push down on the left-side secondary chain tensioner while twisting the plastic guide on the top of the tensioner until it is positioned 90-degrees to the timing chain. The VCT assemblies and secondary chain can now be removed.
Caution: Don’t mix up the VCT units; they are not interchangeable.
Inspection
17. Inspect the individual sprocket teeth and keyways for wear and damage.
18. Check the chain for cracked plates, and pitted or worn rollers. Check the wear surface of the chain guides for wear and damage. Replace any worn or defective parts with new ones.
Caution: If excessive plastic material is missing from the chain guides, the oil pan should be removed and cleaned of all debris (see Cylinder heads – removal and installation). Check the oil pick-up tube screen, too.
19. Check the timing chain tensioners:
Installation
Caution: Before starting the engine, carefully rotate the crankshaft by hand through at least two full revolutions (use a socket and breaker bar on the crankshaft pulley center bolt). If you feel any resistance, STOP! There is something wrong — most likely, valves are contacting the pistons. You must find the problem before proceeding.
20. Install the timing chain stationary guides for both sides, then tighten the bolts to the torque listed in this Chapter’s Specifications.
21. Install the crankshaft sprocket on the crankshaft with the timing marks facing forward.
i.22 Secondary timing chain alignment marks (as viewed from the back sides of the VCT units)
22. Align the marks on the back sides of the intake and exhaust VCT assemblies with the marks on the secondary chains (see illustration). The intake VCT mark must line up between two colored links, while the exhaust VCT mark must align directly with its colored link. Position the VCT assemblies aligned with their camshafts, but not engaged fully (5/64-inch [2 mm] from fully engaged). The exhaust VCT unit on the right cylinder bank must be positioned with its timing mark for the primary chain in approximately the 10 o’clock position, while the exhaust VCT unit on the left cylinder bank must be in approximately the 3 o’clock position; if necessary, turn the camshaft(s) slightly to allow engagement of the VCT units.
23. Rotate the secondary chain tensioner back 1/4-turn, then push the VCT units so they are completely seated on the camshafts.
24. Hold the camshafts from turning by placing a wrench on their flats, then install and tighten the new VCT bolts to the torque listed in this Chapter’s Specifications.
25. Install the left-side primary timing chain with its colored link aligning with the mark on the VCT assembly and the crankshaft sprocket.
26. Install the secondary chain guide, tensioner arm and tensioner.
27. Remove the pin holding the tensioner in the retracted position.
28. Using the special tool (see illustration 4), turn the crankshaft clockwise until the keyway is in the 7:30 position.
29. Align the marks on the back sides of the intake and exhaust VCT assemblies with the marks on the secondary chains (see illustration 22). The intake VCT mark must line up between two colored links, while the exhaust VCT mark must align directly with its colored link. Position the VCT assemblies aligned with their camshafts, but not engaged fully (5/64-inch [2 mm] from fully engaged). The exhaust VCT unit should be positioned with its timing mark for the primary chain in approximately the 10 o’clock position; if necessary, turn the camshaft(s) slightly to allow engagement of the VCT units.
30. Rotate the secondary chain tensioner back 1/4-turn, then push the VCT units so they are completely seated on the camshafts.
31. Hold the camshafts from turning by placing a wrench on their flats, then install and tighten the new VCT bolts to the torque listed in this Chapter’s Specifications.
32. Install the right-side primary timing chain with its colored link aligning with the mark on the VCT assembly and the crankshaft sprocket. Install the secondary chain guide, tensioner arm and tensioner.
33. Remove the pin holding the tensioner in the retracted position.
34. Slowly rotate the crankshaft in the normal direction of rotation (clockwise) at least two revolutions and again bring the engine to TDC. If you feel any resistance, stop and find out why.
35.see The remainder of installation is the reverse of removal.