REMOVING OLD TIMING CHAIN PARTS
1. Unclip the fuel lines (yellow arrows) and rear knock sensor wire (red arrows) from the top of the valve cover, as shown in the picture below (this may not be necessary on all engines).
2. Loosen and/or remove the ten (10) 10mm bolts/nuts that secure the valve cover. On a MKIV, there are 8 captured bolts (yellow arrows in picture below) and 2 nuts on posts (red arrows in picture below). I believe that all ten are nuts on posts on other VR6 engines, but I may be wrong. Once the valve cover is unsecured, pull it up and off of the head, being careful not to damage the cover gasket (it will be reused).
3. The images below show the two camshafts. On the passenger's end are grooves that are used for timing the engine (yellow arrows) and on the driver's end are the camshaft sprockets and upper timing chain.
CAUTION: Once the valve cover is off, be careful not to drop any tools or small parts into the engine.
4. Remove all six (6) spark plugs if you haven't already done so.
5. Crank the engine to Cylinder #1 TDC (top dead center) by slowly hand-turning the crankshaft pulley (red arrow in picture below) clockwise with a 27mm wrench or socket until the little notch on the inner flange of the pulley lines up with the timing mark on the block (yellow arrows in picture below).
NOTE: When doing gross rotations of the crankshaft, always turn the crankshaft the same direction that it rotates when the engine is running (clockwise in the picture below). It's OK to rotate it the opposite way for small adjustments only.
6. The picture below shows a close-up of the notch and timing mark that need to be lined up to set the engine at Cyl. #1 TDC.
7. Once the notch and timing mark are lined up, check the groove on the end of one of the camshafts. The groove should be above the centerline of the shaft - i.e., there should be more material below the groove (yellow arrow in the picture below) than above the groove (red arrow in picture below). If the opposite is true, then the camshafts are 180° out of phase. Rotate the crankshaft one full revolution and line up the notch and timing mark again to set the camshafts for Cyl. #1 TDC (remember, two rotations of the crankshaft equals one rotation of the camshafts).
8. If everything is lined up properly and the engine is at Cyl. #1 TDC, you should be able to slide the camshaft locking tool (VW tool #3268) into the grooves. Instead of using the VW tool, I just used two 1/8" thick pieces of Al plate (purchased at Lowe's) to lock each camshaft individually, as shown by the red arrows in the picture below. You can use pretty much any 1/8" thick metal or dense plastic plate for this purpose.
NOTE: Since the MKIV VR6 has captured bolts that secure the valve cover, no holes need to be drilled in the plate(s) for them to slide into place. However, on earlier VR6s, holes will need to be drilled in the plates so that the plates will fit over the posts that the valve cover is secured to (the VW locking tool already has holes drilled in the necessary places). Also, if you do not use the VW camshaft locking tool, make sure to secure whatever you use so that it can not fall into the engine. The VW tool can not fall into the engine, but something smaller may be able to. I used packing tape attached to the Al plates and wrapped around the fuel lines to keep the plates from accidentally slipping into the block.
9. If the engine is timed correctly, the camshaft tool(s) (VW or improvised) should slide into the groove easily and should be exactly parallel to it. The picture below shows that the gaps between the groove and tool on either side of the camshaft should be equal.
NOTE: Leave the VW or other improvised camshaft locking tool in place in the camshaft grooves until instructed to remove it. This will keep the camshafts from rotating when the upper chain is removed, maintaining the correct valve timing.
10. Remove the upper tensioner bolt (yellow arrow in the picture below) from the back edge of the upper timing chain cover using a 27mm wrench or socket.
WARNING: Do NOT rotate the engine with the upper tensioner bolt removed. Doing so may cause the upper timing chain to jump a tooth or more and would throw off the engine timing. If you are replacing all of the timing chain parts, then this is no big deal since you'll be resetting the timing anyway. However, if you are only replacing the upper tensioner bolt and/or upper guide rail, messing up the timing may result in you having to remove the transmission, clutch, flywheel and lower timing chain cover in order to access and re-time the intermediate shaft.
11. The picture below shows the newer style upper tensioner bolt. There should be a copper crush washer (blue arrow) present to seal the bolt against an oil leak. (Note: Even though the tensioner bolt and crush washer have separate VW part #s, the parts are one piece on the newer style tensioner.)
12. Remove the bolts that secure the upper timing chain cover. There are eight (8) 5mm hex bolts (yellow arrows in picture below) that secure the cover to the head and two (2) 6mm hex bolts (red arrows in picture below) that secure the upper and lower timing chain covers to each other (with part of the headgasket between them - this will be covered in more detail below).
13. Carefully pry the upper timing chain cover away from the head and lower timing chain cover. Be extra careful not to damage the part of the headgasket that extends out from beneath the head and between the two chain covers. This is critical since the headgasket will be reused (unless you are removing the head and will be replacing the entire gasket).
14. With the upper timing chain cover off, you should be able to see most of the upper timing chain parts, as shown in the picture below. The yellow arrows point to the two camshaft sprockets, which are secured to the camshafts with 15mm bolts. The blue arrow points to the shutter wheel on the rear sprocket that is used by the camshaft position sensor (this wheel may be slightly different on earlier model VR6s). The green arrow points to the upper guide rail and the red arrow points to the upper tensioner rail.
15. The picture below shows a close-up of my original upper guide rail. The yellow shading shows the location of a piece that broke off and was causing the rattling noise heard in the sound clip in the link above.
16. If you are only replacing the upper guide rail, skip steps 17 through 19 and go directly to step 20. Otherwise, continue on with the next step (#17).
17. Remove the bolts that secure the lower timing chain cover. There are sixteen (16) 10mm bolts (yellow arrows in picture below) that secure the cover to the block and three (3) 5mm hex bolts (red arrows in picture below) that secure the lower timing chain cover to the oil pan. The blue arrows indicate the position of guide pins used to locate the cover when reinstalling it. NOTE: It has been pointed out by ubercruizinvr6 that the lower part of the thermostat housing on pre-MKIV VR6s needs to be loosened/removed in order to remove the top front lower timing chain cover bolt (above the '01' in the picture below) - see pages 3 and 4 of this DIY thread and/or the DIY UPDATES section below for more info.
18. Carefully pry the lower timing chain cover away from the block and oil pan. Again, be extra careful not to damage the part of the headgasket that extends out from beneath the head and between the two chain covers.
19. With the upper timing chain cover off, you should be able to see all timing chain parts, as shown in the picture below. The yellow arrow points to the part of the headgasket that normally resides between the two timing chain covers, but is now completely unprotected. Be extra careful not to damage/bend the gasket during the replacement procedure below.
20. Remove the upper guide rail by removing the two (2) 13mm bolts (yellow arrows in picture below) and then sliding the rail up and off of the lower guide post (red arrow in picture below). You do not need to remove the guide pin. (Note that the guide pin resides behind the lower chain cover - I suspect that VW used a guide pin instead of a bolt here so that the guide could be replaced without having to remove the lower cover, and consequently, the tranny, clutch, etc).
NOTE: If you are only replacing the upper guide rail, perform step 29 and the appropriate portion of step 35 to install the new guide. Once the guide is installed, perform the engine timing check in steps 40 through 43. Finally, perform steps 48, 49 and 51 through 57 to reassemble everything.
TIP: I recommend that you label bolts as you remove them. Many of the bolts are diameter and length specific to a location and will not fit in other locations.
21. The picture below shows the notch in the inner intermediate sprocket (red arrow) that should be visible when the intermediate shaft is timed correctly (MKIV Bentley step #7 and Figure #21 on page 15d-16). Also, the yellow arrow points to the piece of my upper guide rail that broke off and was rattling in between the block and the inner intermediate sprocket.
22. In order to remove both the upper and lower timing chains, it is necessary to create some slack in the chains. The easiest way to accomplish this in both chains is to remove the intermediate sprockets. In the picture below, the yellow arrow points to the inner intermediate sprocket and the red arrow points to the outer intermediate sprocket. To remove the sprockets, remove the 15mm bolt (blue arrow in picture below)that secures the sprockets to the intermediate shaft. In order to do this, it is necessary to counterhold the crankshaft to keep it at Cyl. #1 TDC. You can use one of the special VW tools to do this, or you can just have a friend counter hold the crankshaft pulley with the 27mm wrench or socket and a long breaker bar. The intermediate shaft bolt is torqued on fairly tight (74 ft-lbs or 100 N-m), so it will take a good amount of force to loosen it. If the crankshaft accidentally moves slightly while loosening the bolt, turn the crankshaft back to Cyl. #1 TDC BEFORE removing the intermediate bolt and sprockets. (Note: Leave the camshaft locking tool in place while loosening the intermediate shaft bolt. As long as the crankshaft does not move significantly, there is no harm in leaving the tool in the camshaft grooves.)
23. Slide the outer intermediate sprocket off of the inner intermediate sprocket and then remove the upper chain from the camshaft sprockets. (Note that the inner and outer sprockets are keyed so that they will only fit together one way).
24. With the upper chain removed, the upper tensioner rail should fall down through the hole in the exposed headgasket, as indicated by the red arrow in the picture below. The tensioner rail pivots on a pin, which is indicated by the yellow arrow in the picture below.
25. To remove the upper tensioner rail, simply slide it off of the pivot pin, as indicated by the yellow arrows in the picture below. You do not need to remove the pivot pin.
26. Remove the lower tensioner unit by removing the two (2) 5mm hex bolts indicated by the yellow arrows in the picture below (the tensioner will fully extend when removed if you don't hold the rail and body together or secure it with a U-clip like the one that comes with a new tensioner).
27. Slide the inner intermediate sprocket off of the intermediate shaft (note that the shaft is also keyed so that the sprocket only goes on one way) and then remove the lower timing chain from the crankshaft sprocket. Finally, slide the lower guide rail off its guide pins, which are indicated by the red arrows in the picture above. You do not need to remove the guide pins.
28. All of the timing chain parts that need to be removed should now be removed.
Modified by VgRt6 at 4:01 PM 2-26-2005