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Getting Started

The first thing to know when getting started on a dunebuggy project is what you have. The most difficult part is making sure the parts you are ordering actually fit. Dune buggies specifically can be created using a huge assortment of parts and pieces. While VW Beetle parts can be ordered from us simply by starting years, the dunebuggy builder faces the challege of possibly having many years of parts variation all wrapped up into 1 vehicle. While the task may seem difficult, our staff at Appletree is highly trained to determine what parts you will need by only having to ask you, the builder, a few very simple questions. Please understand that it doesn't help us much at all to be told a year your dunebuggy was made but rather what it was made of.

To start out we will start in the front of the car. There are basically 2 versions of the VW front suspension that we deal with: King Pin and Ball Joint. At a quick glance these two front beams may look very similar but underneath they are very different. Fig. 1 shows a VW King Pin front end which is usually referred to as early because it was the front suspension used from 58-66. It is easily identified by the shock towers. On a King Pin front beam, the shock towers will rise straight up from the beam and angle slightly back towards the driver. The shocks on this beam will bolt horizontally into the beam. The other way to identify this front end is to look at the attachment point for the spindle to the control arms. In a King Pin setup, linkpins are used to attach the spindle carrier to the control arms. Shims are used to set camber. A king pin will attach the spindle to the carrier by being pressed through brass bushings on both ends of the carrier and through the spindle. Most King Pin front ends will use a 5 bolt brake drum. The tie rods on a King Pin are always the small diameter ends. Fig. 2 shows a Ball Joint front end. Unlike the King Pin beam, the ball joint shock towers will rise straight up and curve outwards over the wheels. The shock will then bolt vertically, up through the beam. The spindle assembly is held on with upper and lower ball joints. Ball Joints will typically take a 4 bolt pattern drum. While it may seem cut and dry, the ball joint beam adds a variation in parts from 67-68. Ball Joint front ends will cover all the way until 1976. The variation consists mostly at the brake. There is a width difference on brake shoes with the years. 67-68 will use a skinny brake shoe while the 68 and up will use a wider shoe measuring 1.5" across. The easiest way to determine the year of the Ball Joint beam is to measure the spindle diameter. 67-68 will use the ball joint tie rods with the smaller diameter stud and the 68 and up tie rods will use a bigger stud. Also keep in mind that if you have any other beam configuration other than stock VW, for example aluminum or warrior-style front beams, then you will have a King Pin. These beams are unfortunately not able to be easily interchanged. The distance between the horizontal tubes on the front of the beams are different and therefore are impossible to swap unless you are comfortable doing fabrication work.
Fig. 1Fig. 2

The next area of interest in determining what you are working with is the rear suspension and transmission. I will start with transmissions. Early VWs (58-66) used the swing axle transmission fig. 3. These are very easy to identify by looking at the axle area. If your axle is in a tube and you cannot see it turning then you have a swing axle. One of the main differences is that the swing axle will only pivot at the transmission. This doesn't work well for offroading since the more travel that is achieved the greater the camber at the wheel. The swing axle used a 5 bolt drum. The hardest thing when working with a swing axle is determining if you have a short spline axle or a long spline. The easiest thing to do is to remove the brake drum and measure the depth of the center hole. The other style of VW beetle rear suspension is the IRS or Independant Rear Suspension fig. 4. This is the ideal rear end to use on a offroad application. IRS suspensions will use a CV joint on both ends of the axle and allow the wheel to stay perpendicular to the ground throughout its range of travel. All IRS rear ends use a long spline stub. They typically use a 4 bolt drum but 5 bolt long spline swing axle drums will also fit. Popular upgrades to this drivetrain are stub axle conversions to allow the use of Type II or 930 CV joints. One added variable to the IRS system is the transmission can be easily swapped out for the stronger VW Bus transmission. This is a very common procedure. There are 2 types of bus transmissions that are used, the 002 transmission Fig. 5, and the 091 (6 rib) fig. 6. The 002 can be identified by the 3 ribs that run across the differential area while 091 transmissions have 6 ribs that run across. There is however a 5 rib 002 case that is more rare. The 091 is the most sought after of the two because of the strength of the internals and a low ring and pinion ratio. When ordering any suspension kits or drive flanges, it is important to know what model tranny you have; whether it is a swing axle or IRS beetle trans or a 002 or 091 bus trans.

Clutches are one of the most commonly misordered parts. There are two different clutch setups for VW. The first is what we call the early version and came mostly in the swing axle transmissions. They are identified by the centering ring in the middle of the pressure plate Fig. 10 as well as the throw out bearing that has detachable clips Fig. 11. They come in 180mm diameter as well as 200mm. The 200mm is the most common. The IRS or "late style" uses a pressure plate without any centering ring Fig. 12. The throw out bearing will also have built in clips that will snap it into the throw out arm. The most easily identifiable difference is that the late style system uses a 3 bolt centering tube that is bolted to the transmission and the throw out bearing glides back and forth on it, centering it on the pressure plate. ANY MISMATCHING OF PARTS BETWEEN THESE MODELS CAN RESULT IN DAMAGE TO THE PARTS and will cause a lot of frustration while trying to get the motor and trans together. It is very important when ordering replacement parts that you know whether or not your pressure plate has a centering ring and whether or not your transmission has a centering tube.
Fig. 10Fig. 11Fig.12

Spring plates are another area of difficulty when ordering parts. There are 3 different length torsion bars and coinciding spring plates that are available, 21-3/4", 24-11/16" and 26-9/16". While measuring the torsion bar is the quickest way, you can determine if it's a 21-3/4" torsion by looking at the cover that the spring plate hooks to on the torsion housing. If the cap is solid then it is the short version. The 21-3/4" torsions were stock on swing axle rear suspensions but was a good upgrade on IRS suspensions that had the longer bars since the longer bars oftentimes limited tire size.

The last area of interest on your car will be the engine. Most engines used were Type 1 VW Beetle motors. The Type 1 motor has a few variations that you should be aware of. The most common and most upgradable version is the 1500-1600cc dual port motor fig. 8. To identify what motor you have please see our model identification page located here. The least favorable is the 1200 single port engine. The 1600 dual port is the foundation of a great motor. There is a large assortment of aftermarket parts available. Unfortunately the single port option was as popular but lacks the availability of aftermarket upgrades. If your engine doesn't have a number under the generator stand then it was most likely built from a new aftermarket case which will be at least a 1600cc. I say at least because the only way to really know what size the motor is you would have to take the head off and actually measure the cylinder. There are 5 possible piston kit sizes that can be used: 85.5mm is stock; 87mm is a 1641 and can be installed without doing any machine work to the case or heads; 88mm which is a 1688cc but isn't that common because it gets a fairly thin cylinder wall; 90.5mm is a 1776 and shares the same engine bore cut as a 92mm at 1835cc; and 94mm is the biggest and yields a 1915 and is 10 to 1 the most common big bore kit to install. Many of the early motors used a 4 dowel crank and flywheel. Under high performance use, this is usually the first thing to fail. The upgrade would be the 8 dowel setup. This can be achieved by either buying a new crank and flywheel, or buying the dowel jig tool and drilling to add 4 more dowels.
Fig. 8