VW engine basics
This page will be a step-by step article on a stock Volkswagen bug engine breakdown and build.
There were many versions of the air-cooled VW engine, but this article will concentrate on the early bug (pre-'79). Excluding the injected motors, this is as basic as a car engine gets.
- First, using a long throw floor jack, raise the rear of the vehicle almost as high as the jack will go (explanation later) and lower it onto jack stands, placed under the rear torque tubes.
- Next drain the oil, disconnect the battery, and disconnect the wiring from the motor -- this is the hot lead to the coil, electric choke, alternator/generator, and oil pressure switch. If there's any confusion, mark the wires as to what they are and also where they connect.
- Remove the rear pan, making sure to remove the heat riser seals, and the engine heater flexible tubes.
- Next remove the throttle cable from the carb -- should be an 8mm (5/16).
- Now,it's time to crawl under the car, locate the fuel line (on the driver's side), and pinch it off, or, disconnect it from the steel line on the engine and put a plug into it (a golf tee works good), making sure that you pull it off from the engine end.
- Reach above the clutch wing nut and pull the throttle cable out of its tube. Remove the heater tubes and cables (if they're still there) and put to the side.
Now you're ready to remove the mounting bolts. There are only 4 on the engine (maybe 3, depending on who had it out last). There are 2 on the top, one above the clutch cable and one opposite it on the other side (also the top starter bolt). Depending on the model,you may have to have someone hold a wrench on these (17mm/11/16") -- these 2 nuts are in the engine behind the fan shroud,you have to uncomfortably reach around the rear to remove them. If you don't have someone to hold the wrench, clamp a Vise-grip on the nut to keep it from spinning.
- Take one off and loosen the other one but do not remove it!
- Put the floor jack under the round oil drain and take the weight off the engine.
- Now, remove the 2 lower nuts and the last top nut.
- Grab the tailpipe (1 of 2) and with your other hand grab the top of the fan shroud, and slowly pull the engine to the rear. When it gets close to contacting the rear of the car, drop the jack a little, continuing to wiggle and pull. If this seems difficult, raise the jack a tad, and keep wiggling until it's free.
When all is clear, drop it slowly the rest of the way down. If it won't clear the rear apron, tilt it forward, or, let it off the jack onto the floor. They don't weigh much, so just pull it out. Have a friend help you pick it up and put it on a workbench.
Before picking the motor up (by hand, or with a lift), place some cardboard or a fender blanket under it to soak up excess oil, and set it on the bench.You can use an engine stand, but unless you have a VW specific stand, it's kind of a pain because a VW case comes apart down the center.
- Now, remove the the throttle tube, pull straight out and place to the side. At this point,it's a good idea to use coffee cans to put like items in same can, this helps to mark them also.
- Next, remove the rear pan and put aside.
Now it's time to remove the generator and shroud.
- If this is a dual port engine with the offset oil cooler, remove the cooler cover and snorkel (if it's still there), and set with other sheet metal.
- Disconnect the distributor from the coil, then take the belt off the generator. Depending on the generator, the nut will be either a 21mm (13/16"), or a 19mm (3/4"). There should be 2 slots in the pulley by the body of the body of the generator. Place a large flat blade screwdriver into one of the slots and brace against one of the screws that hold the ends on. Remove the nut and the rear of the pulley (it's 2-piece), making sure to pay attention to the shims on the outside and between the 2 halves as this is your belt adjustment.
- Pop the plug wires out of the looms and pull aside. Loosen the generator strap (13mm or 1/2"), and slide out of the way. On each end of the shroud you will see a screw or a 10mm bolt. Sometimes you just have to loosen them, sometimes they must be taken out. Lift the shroud up and to your right and set aside.When this is clear, remove the plug wires from the plugs and remove the distributor cap and rotor.I normally don't remove the carb,but that's personal preference. Major thing now, remove the intake and carb as a unit,the four bolts that hold the heat risers to the exhaust are usually a real bear to get loose without twisting off,the best ways I've found to loosen them is #1.heat them with a torch(propane is ok)until they come loose or,Peen them with a chisel or punch and give them several sharp raps(really,hit 'em like you love 'em).If this doesn't work, twist them off,they make self-tapping bolts specifically for this purpose,just drill them out and put a new bolt in. At the bottom of the intake tubes you will see 2 10mm nuts or bolts on each side,remove these and take the intake off,taking care not to tip it over. Now it's time to take the muffler and heater boxes off,I usually leave the sheet metal on the bottom there and remove it with the heater boxes.To remove the muffler,first,the two clamps that hold the muffler to the heater boxes,if the 10mm bolts won't come loose,break them off,the kit with the clamps,new bolts and nuts is cheap,cheap,cheap.The composite seal and washer between the muffler and heater boxes is easily split with a sharp chisel,if the joint seems rusty,tap around it with the ball end of the hammer until its free.The best way I've found to get the nuts off the exhaust flanges is to take a long,sharp chisel and split the nuts if they aren't already free,being careful not to damage the threads on the stud,now,take the muffler off. The heater boxes are very similar,on the bottom sheet metal,there are 2 screws on the bottom of the case inside on the case and 2 more at the flywheel end of the case. Remove these and remove the flange nuts the same way as on the muffler. Set them aside and look at the pulley end of the engine,on each side,under the upper sheet metal there are 2 deflectors,each held on by 2 screws.take them out,pay attention,things are simple,but not foolproof.With these pieces off,take the 2 top deflectors off,2 screws on each side. now you are finally looking at the motor. I'll add more when I can,I hope tomorrow. Tom I apologize,my father has been in the hospital and I've been up at the VA with him,I'll post more when he's better.