Foreign service

Motor,  Aug 2003  by Marinucci, Dan

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Swing that timing belt round and round! There are four important steps to learn if you want to be able to do the Volkswagen ABA engine t-belt tango.

Replacing a timing belt on a 2.OL Volkswagen engine isn't extremely difficult, but it certainly demands attention to detail. I've heard lots of horror stories about technicians who did this job carelessly and regretted it later. Therefore, this month I'll focus on details that will help you do it correctly the first time.

This article concerns the popular ABA version of Volkswagen's 2.OL engine. Over the last 10 years, the ABA has appeared in a variety of VWs, including the Cabriolet, Golf, GTI, Jetta and Passat. The easiest way to identify it is to look for the letters "ABA" stamped into the front of the block above the crankcase breather. be sure you have the appropriate shop manual or timing belt service guide for an ABA before you begin.

Unlike most other engines you've serviced, this one doesn't have an official, mandated timing belt replacement interval. However, belt manufacturers as well as VW specialists recommend 60,000 miles as being a reasonable replacement interval. Considering that this is an interference engine, you'll want to remind customers that a simple tbelt job is always much cheaper than replacing bent valves-or worse.

The most critical part of a successful, routine t-belt job on an ABA engine is identifying and aligning all the timing marks. At the very least, slowly rotate the engine until three marks are properly lined up at the same time: camshaft sprocket, distributor rotor and flywheel. First, locate the letters "O" and "T" on the camshaft sprocket and dab them with white paint so they're easier to see. In photo 1 below you can see that these letters are on either side of a "valley" in the cam sprocket.

Next, identify O.T. and a little arrow on the rear timing cover and highlight them with white paint, as I've done. When the marks are correctly aligned, this arrow should point directly at the valley between the letters "O" and "T" on the cam sprocket.

The second timing mark is on the flywheel. Remove the access plug from the bellhousing and on manual-trans cars look for either a deep notch or a "O" on the flywheel. Photo 2 shows the common "O" mark. Line up the deep notch or the "O" with the little pointer that's cast into the bell-housings access hole.

Aligning the timing mark on an ABA engine with an automatic trans is a little bit trickier. The drawing at right shows that the bellhousing's access hole is somewhat oval-shaped, with a flat lower edge. On an automatic, the timing mark is also a "0." When the marks are aligned correctly, the flat lower edge of the access hole will bisect the "0" on the flywheel, as shown.

The third important timing mark is a deep notch in the top of the distributor housing that points toward the rear of the car. This notch, which happens to line up with the No. 1 cylinder on the distributor cap, is shown in photo 4. When you remove the distributor cap, you'll see that the cam position sensor's black dust cover is notched out to reveal this notch. Dab this notch with white paint to make it more visible. When the cam sprocket and flywheel marks are both properly aligned, the distributor rotor should be pointing directly at this notch in the top of the distributor housing.

Again, the very minimum you must do is properly align all three of the above-mentioned timing marks before proceeding with this timing belt replacement. Rob Stafford, the European car specialist at AIR Import Repairs, Inc., in University Place, Washington, cautions MOTOR readers to examine the rotor location very closely during this procedure. For example, suppose the rotor tip is just leading ahead of or just trailing behind the distributor notch. If so, then it really should be pointing at exactly the same position when you double-check the timing marks after installing the new belt. Unfortunately, you can't move the distributor wherever and whenever you want because the distributor hold-down bolt slides between two locating pins pressed into the base of the distributor.

This engine has a cam belt-driven intermediate shaft. When the rotor tip is misaligned after a timing belt job, the intermediate shaft sprocket is usually off a tooth or two, Stafford told me.

Don Stallman, owner-operator of Integrity Honda-VW Repair in Canton, Ohio, agrees with Stafford but also recommends an extra step to this month's timing belt tango. he noted that there's a timing mark on the intermediate sprocket that resembles a chisel mark. It may take a mirror and some patience to find it, but it's there. When all three of the critical timing marks described earlier are aligned, this chisel mark happens to line up with the timing mark on the front drive belt pulley.

Stallman stresses that lining up this fourth set of marks minimizes or eliminates the risk of the distributor rotor being misaligned after a t-belt replacement. So, patiently locate the chisel mark on the intermediate sprocket and dab it with white paint. Then find the timing mark notch on the front drive belt pulley and paint it white. Next, reinstall the harmonic balancer and this drive belt pulley with the bolts finger-tight. Now when you align all the timing marks as described earlier, be sure the front pulley mark and the chisel mark on the intermediate shaft also line up.