Modified Type 4 engines have never been as popular in the UK and USA as their Type 1 counterparts. However, European VW enthusiasts have long recognised the tuning potential of the Beetle’s big brother and although the total number of performance Type 4 engines I build is small in comparison, their popularity is on the increase.

The basic design principles of the Type 4 engine are similar to the Type 1 and with few exceptions, none of the parts are interchangeable. One of the major advantages the Type 4 has over the Type 1, is that it’s crankcase is made of aluminium, whereas the Type 1 is constructed from a magnesium alloy. Although the aluminium case is heavier, it is also much stronger. Very rarely will you see a Type 4 case with badly pounded bearing saddles; even after very high mileage. The softer magnesium alloy of the Type 1 case will often show signs of wear in this area and will need line boring or replacement before being put back in to use.

In stock form, a 2.0 litre Type 4 engine won’t transform your daily driver into a high performance Autobahn cruiser. Like any other engine, the Type 4 responds to improvements in camshaft, cylinder heads, carburetion and capacity increases. Availability of aftermarket tuning parts is tiny compared to the wealth of goodies on offer to the Type 1 crowd and comparatively, prices are much higher. E.g. a set of 103mm pistons and cylinders will set you back at least £400.00. A big bore kit for Type 1: around £150.00. But a well built performance Type 4 engine can provide substantial amounts of long lasting torque and horsepower.

In standard form, the Type 4 cooling fan is mounted on the end of the crankshaft, making the engine too long to fit within the confines of a Beetle engine bay without having to resort to unsightly bodywork modifications. The common conversion is to fit a Porsche 911 fan and alternator unit on top of the engine, with appropriate shroud (fan housing), alternator strap, dipstick tube etc. Various companies offer kits to complete this installation. To ensure the 911 fan housing doesn’t foul the engine lid when fitted to a Beetle, the crankcase must be machined to allow the fan to sit low enough for clearance. Kits which utilise an adapter block that bolts to the top of the crankcase without requiring any machine work are fine for offroad type vehicles with open engine bays (e.g. buggies, rails and bajas) but if you intend fitting the kit to a full bodied saloon, the case must be machined.

Sample specification for a Type 4 2366cc engine Crankcase:apart from the very earliest of cases, which were made from magnesium, any case will be suitable as a basis for the build: 1.7, 1.8 or 2.0 litre Crankshaft: the stock Type 4 engine was available in three capacities: 1.7, 1.8 and 2.0 litres. The 1.7 and 1.8 engines have a 66mm stroke crank. The 2.0 litre has a 71mm crank. As a starting point, I recommend you locate a 2.0 litre crank. Longer strokes are available - either welded stock based cranks or completely new forgings. Conrods: You’ll also need the 2.0 litre rods - the rod journal has a smaller diameter than the 66mm cranks. The stock rods are strong enough for all but the most radical of engines. Camshaft: I generally use Webcam or Eurorace cams. Grind dependant on application Pistons and Cylinders: The pick of the bunch is J & E 103mm. This gives a capacity of 2366cc when used with a 71mm crank. I don’t recommend this size for use in a Type 2. Cylinder Heads: The best of the stock heads is the Porsche 914. Second choice would be the 1.8 litre VW head. However, Type 4 heads are known to have valve seats come loose, so it’s probably wise to have the seats replaced and while you’re at it, fit larger valves. Carburettors: Common set up is twin carbs e.g. Weber IDFs or Dellorto DRLAs. How about engine management or a turbocharger?

If you need further info on the tuning potential , machine work or performance parts for the Type 4 engine, give us a call.

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