Replacing a VW Golf 1 cambelt
If you've reached this page from a search engine (say www.google.com), then you are here for one of two reasons:
- You have decided that you want to attempt a cambelt change all on your own and you are looking for how to go about doing this.
- You have attempted to change the cambelt, and now the car won't start and you are crapping yourself over the potential damage that you may have done.
It's a fact of human nature that we tend to try things first, then look up how to do it properly. Either way, I'm going to explain how I did the change on my VW 1300 engine after losing all the markings once the old belt was off. This is the worst-case scenario that one can possibly recover from.
The worst case scenario that one cannot recover (cheaply) from is when you do it wrong and damage the valves, the pistons and your self-confidence; but I won't cover that for the very obvious reason being which, if you have encountered this scenario, no amount of advice over the internet can possibly turn your heavy metal paperweight back into a running engine.
Note that this guide is *not* specific to the VW Golf 1 engine; this guide will apply to any 4 stroke internal combustion engine that uses a cambelt to control the valve timing (even, theoretically, diesel engines, should they have a cambelt).
- Engine Timing Theory
- Setting the pistons and valves with no marks (An unedited copy of a posting I made to usenet early in 2006, when I replaced my cambelt)
- Common problems
, generally have a transversally-mounted engine which does not allow the radiator fan to be driven off the the engine itself.
The following is a post I made to usenet early in 2006 when I changed (and messed up) my cambelt on the vw 1300 engine.
Hello all I'm writing this down in the hope that it will help other home-mechanics who search google for an answer. The problem I've found is that the cambelt also turns the distributor. When I replaced the cambelt, the gear which turns the distributor (off the cambelt) had turned, so the ignition
timingwas off. Since I had already messed up the valve *timing* while trying to figure out what was wrong, I now had both the valve and ignition *timing* out, and the cambelt was off the engine. 1. I "found" TDC by using a long screwdriver down the #1 cylinder. The procedure is to get the piston near TDC, and rock back and forth over TDC while the screwdriver was in the spark plug hole. I marked the point where the screwdriver stopped upward motion (turning the engine with a spanner), marked off the position where the screwdriver started going down and took the middle of the two marks as TDC. 2. I set the distributor by merely spinning the toothed gear near the crank gear until the rotor was under one of the wires on the distributor cap (any wire will do, you then just call that #1). 3. I turned the camshaft (spanner again) and "rocked" #4 (this means: turn the camshaft until the inlet valve and exhaust valve for #4 are just about to open/close. Ideally the cams would be holding the valves in the same position with no clearances). This ensured that I had #1 valves at the maximum clearance. I marked of this position on the outside of the head and the camshaft gear wheel. 4. I then worked out the firing order from the valve positions for all the cylinders (on my car, this worked out to 1-3-4-2). 5. I installed the new belt, making sure after the belt was tensioned that none of the gear-wheels had shifted position (which is why I marked them all off before starting) and that the tensioner was tight. 6. I set the firing order on the distributor cap. 7. I turned the engine with a spanner two full revolutions. This I did to check whether any of the valves were going to touch the pistons. If you turn the engine like this first, then at least you won't damage the valves because you'll feel the resistance if a valve touches a piston. 8. I started the car (it started on the first turn off the key - YAY!!!) 9. I then switched the car off, and set the ignition *timing* statically; This is done by turning the engine until the *timing* mark is visible and near the point of reference on the cambelt cover and when #1 is getting ready to fire (i.e. the rotor must be about to fire #1). I took a spark plug, put it on the #1 wire, held it against ground and twisted the distributor back and forth until I got a spark on the plug (obviously the ignition must be on while you do this). I turned the distributor and set it at the point that a spark was produced. This is good enough to ensure the car starts. Later this week, once I fix the leads on my *timing* light, I'll set the *timing* proper for unleaded petrol. Whew... Hope that this post is helpfull to anyone else with a 4-cylinder watercooled VW - AIUI most of the VW engines from 80's & 90's have the same design, with the cambelt controlling the rotor (first car I've worked on that had this arrangement was this car! All the others had a different crank-gear or *cam*-gear arrangement for turning the rotor); hopefully anyone else who runs into the same problem will read this (google is your friend:-) and realise that the cambelt is on proper, it's just the rotor thats off.
Well, there are a few, but I haven't the time right now to detail them, so drop me a note (see the contacts page) and let me know what problems you've had.
Alternatively, you feel that I got something wrong? Is the process inaccurate? Well, then help me set it straight and send me a correction.
The older Audi 100 and 500 1.9L and 2.2L engines were front-wheel drive cars with longitudinally-mounted engines. This meant that they had an extra long wheelbase forward of the front axel as the gearbox had no propshaft behind it, but had two CV joints coming out each side of the gearbox, which itself was mounted directly under the gear-lever. It also meant that there was very little (or no) torque-steer problems.
Which is why your FWD card has a fan that has to be electrically operated. The transverse-location did not allow for the more reliable and efficient mechanical/hydraulic fan of longitudinally-mounted engines.