(Vanagon Diesel -> Gasoline)
by James Sly
VW & PORSCHE January/February 1989
So what's the slowest Volkswagen you've ever driven? An old split-window van, maybe? Or a Diesel Vanagon? How about a Diesel Vanagon fitted with the Westfalia Camper option? How about a Diesel Vanagon fitted with the Westfalia Camper option and 70 thousand miles on the clock? There couldn't be much on the road slower than that.
And David Andrews, owner of said 1982 Vanagon Diesel L Westfalia, was tired of always bringing up the rear. It was a great used car deal when he bought it in 1985 for $6500 - the sticker on the Vanagon showed that it first sold for more than $17,000 but ...
While the camper part worked great, as Westfalias always do, the Diesel part was slow. Real slow.
At first, David felt that he could live with the sluggish performance. After all, it was a vehicle to relax in, a recreation vehicle, right? Even so, the virtue of patience is sorely tried in such a slug and David soon became frustrated at how slow it really was - like about 21 seconds 0 to 60, for example. It was true that the vehicle could hit 65, on a gentle downhill slope at any rate, but it was also true that it was hard-pressed to maintain that speed. And on freeway on-ramps, David vows that he could see the drivers behind him swearing and shaking their fists, thinking that he was taking it easy when he really had the Vanagon flat-out floored.
Compounding the problem, David was not raised on slow cars. Volkswagens, yes. Slow cars, a resounding no. A 20-year acquaintance of hotrodder Darrel Vittone of Riverside's Techtonics Tuning, David was also an employee of EMPI, the most famous VW tuner of the '60s and early '70s. As an added distinction, David has the honor of being one of the few drivers to ever win a major NHRA drag event in a Volkswagen, when his 1967 Beetle, running in A-modified Compact, beat all of the factory Chevy, Dodge and Ford entries to win class at the 1975 Pomona Winternationais. Volkswagen, yes, but this Beetle had the habit of running consistently in the 12s-slow like a cheetah.
Anyway, the Diesel was considerably cheaper than a gasoline Wasserboxer Vanagon would have been and it fit the budget. David lived with the aggravation for another 14,000 miles, planning a conversion to a gasoline engine at some later point. Slowly but surely, the Vanagon went from Mexico clear to Alaska, and back and forth across the U.S. two times. (David notes that a Diesel Vanagon gives one the mentality of a bicyclist: Terrain that looks flat from a car really isn't to the cyclist or Vanagon Diesel owner. Take Kansas as an example: For someone in, say, a GTI, going east to west is level, if boring, terrain. For David's Diesel, crossing Kansas was a steady and exceptionally dreary uphill grind, with a top speed of 55 mph. Finally, perhaps mercifully, the Diesel block cracked at 84,000 miles. Rather than rebuild the Diesel, David opted for a gasoline engine swap. Now that Techtonics is concentrating on research, development and sales, and doing little installation work, David is doing some installations of the potent Techtonics 2020 motor. He knew firsthand about the durability and power that Techtonics parts offer, so naturally that was the route he elected to take. He used an early, pre-1983 1600 block as basis for the swap.
In converting the Vanagon from diesel to gasoline, it would have been a lot easier to simply use carburetors, but the advantages of sophisticated Bosch CIS injection were desired. After all, with the camper's weight to haul around, low-end torque and driveability are all-important - and those are two things that carburetors simply do not deliver. And while the fuel mileage with a heavy aerodynamic brick like the Vanagon is not great, the added gasoline that carburetors would burn would have been an extra penalty.
Any engine conversion requires attention in several critical areas: Adapting the new motor to the old transmission, getting it mounted properly, getting the cooling system hooked up and working with the added horsepower, and getting intake and exhaust systems that fit and work.
One of the joys of this conversion is that no adapter is required for the engine block, either to the transmission or to the motor mounts. The stock Diesel bellhousing allows a direct bolton of the gasoline block: tilt it over at the same angle as the Diesel motor and it's a perfect mount. The new gas motor is fitted with the slick stock cast aluminum oil pan off the Diesel.
David solved the exhaust system problem by using a 1980 Dasher dual-downpipe exhaust manifold, which required slight modification to the stock Vanagon motor mount. Next time around, David will use a late-model Dasher unit that will not require any mounting mods. The resulting dual downpipe exhaust is an effective, torque-boosting 4-2-1 system, and finishes with a custom exhaust and muffler. The current system does not use the Lambda oxygen sensor for increased fuel mileage, but David does plan to upgrade soon.
On the induction side, the injection air intake manifold is off an early Rabbit, with '79 injection system components supplying the fuel. The manifold has had Techtonics welding and porting to allow fitting the larger Neuspeed throttle body. There's a special knock-out Plug under the rear fenderwell to allow adjusting the idle speed screw.
The fuel filter, pump and accumulator are mounted up by the gas tank on fabricated mounts. For future conversions, David would simplify the installation by using the late-model Golf components that are already mounted as a unit.
A large 80mm diameter airflow sensor plate, as used on the early cars and on 1983-84 GTIs, measures air and sends out the fuel on the injection system. Each line had to be custom made and fitted from the fuel distributor to the injectors and cold start valve. The material was not easy to come by. Many companies have the line available in one-meter or 39-in. lengths, but that wasn't a help as this project needed longer lines, with the longest being a 54-in. line to the cold start valve. David did finally find the fuel line and get the custom lines made up.
The Vanagon s transplanted engine features one of Techtonics' GTI heads to fit on the earlier blocks. Stock VW GTI 40mm intake and 35mm exhaust valves are used for their good wear characteristics and trouble-free operation. Valve actuation on the solid lifter head is by VW's G-grind camshaft, chosen for both good low-end torque characteristics and long lobe life offered by a German billet cam.
In the block is a Techtonics stroker crank, with 88mm stroke. Combined with Techtonics 82.5 pistons, the motor displaces 1881cc or 115 cu. in. The compression ratio is 9.5:1, helping both performance and fuel economy.
Stock cooling components have had no problems keeping up with the substantial infusion of added Techtonics horsepower. The cooling system changeover was not too difficult to engineer, which is one reason that converting a Diesel is most feasible, as all the water lines are in the right place. There was no cutting of sheet metal or extra water lines to run. Some of the water lines were changed around and some copper fittings were employed to allow the use of hoses less costly than the factory pieces. If you've seen some of the contorted examples of specially molded Vanagon hoses, and looked at the prices, then you know what we're talking about.
The water reservoir was moved to the original battery box location and the battery box moved to the front of the right rear fender well, where the battery was located on VW buses in days of old.
Air conditioning made the engine swap considerably more difficult, as David fabricated almost everything in the sophisticated, effective AC system. But, if you live in a place like Riverside, California, where summer temperatures soar into the 100s, you too would view the work that went into creating an air conditioning system for the Vanagon as part of the basics.
There's a lot of air to cool in a Vanagon and it took some work to come up with a system that really works. David's super air conditioning system uses a Sankyo 508 compressor as currently seen on most VWs - A Diesel Rabbit factory AC mounting bracket is used with the alternator moved to the "up" position and the compressor mounted below so as to clear the stock engine cover. It took careful belt sizing to match up the AC compressor and the alternator: David reports spending five or six hours just getting the correct belts, as a belt that's too long allows the alternator to go too high and touch the engine cover.
The custom AC installation has a total of three condensers, with large units located in front of the radiator, behind the passenger side headlamp and a smaller unit under car. Inside, there's two evaporator units in specially fabricated housings, one in the rear of the large interior and one in the front. A GM-style accumulator is mounted to improve AC system performance. And it really works. We took a test ride on a 90-degree high-humidity day and were blown away by the quick cooling power. It seemed more like a refrigerated delivery truck!
Separate controls are mounted for the front and rear air conditioning. In order to help control the electrical demands on the system, a trick wind activated switch shuts off the front condenser fans over 25 mph, with a solid state relay incorporating a timed delay to prevent rapid on-off fluctuations near that speed. A two-speed radiator fan from the newer A-2 chassis Golf/ Jetta is used, with another, a stock fan, timed delay on high speed to provide additional fan power.
The resulting all-VW Hybrid Vanagon is a pleasure to drive. Though the vehicle's still an aerodynamic brick, the new motor will push it to 90 mph. ("Toto, I think we've finally made it out of Kansas. . ") We didn't have a chance to time the acceleration, but subjectively the car is noticeably quicker than a Wasserboxer gasoline Vanagon. Coupled with the low-geared diesel four-speed, the Vanagon jumps out, even with the sophisticated air conditioning on and three or four on board. Fuel mileage with the Diesel was about 23-24 mpg. The more powerful gasoline engine delivers a respectable 18-19 mpg. The Diesel was rated at 49 hp. We estimate that the 1881 is putting out about 125 hp, a modest 255-percent improvement.
The engine turns 4000 rpm at 65 mph, which is a bit buzzy. David feels a better choice of transmission would be a gasoline Wasserboxer 4-speed or 5-speed, which would require a simple bellhousing change to use. It's likely that a different transmission would improve the fuel mileage as well.
In many respects, this is not a simple swap, but it's certainly an interesting one. Used Diesel Vanagons are a real bargain in the current market. The added horsepower of a gas high performance motor can turn a Diesel Vanagon into a much more desirable vehicle. Tune-ups and parts are easy to get, as is service, and the sophisticated air conditioning system that David constructed is mere icing on the cake.
But, like many other upgrades, this is one project that is not quite finished. We mentioned the future Lambda sensor, but David has some other changes in mind: perhaps a Techtonics 2020 motor for long hills. One thing's for sure, David might return to Kansas again, but next time he'll find it more level than he remembered.
Note close proximity of alternator to top of compartment. Ducting and cooling shroud on alternator is off Porsche 928 and provides cooling air In tight confines of Vanagon's engine compartment.
Dual outlet cast iron manifold from an early Dasher required slight modification of stock motor mount. Custom dual outlet downpipe helps build power in 1881cc motor.
View from underneath. On right, special air conditioning condenser Is visible. CIS pump and accumulator are visible to right of water plumbing.
Two.speed radiator fan from newer A-2 chassis Golf/jettas fit stock diesel Vanagon location. Timed relay and "wind" switch combine to help keep electrical demands on battery reasonable.
1341 Century Avenue
Riverside, CA 92506
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