VW & Audi Diesel Engine History

Diesel Engine History 128x128
Gear case (3)Volkswagen began their chapter in USA Diesel History with the 1.5 liter motor. It was IDI or Indirect Diesel Injection, meaning the fuel was injected into a steel prechamber which was pressed into the aluminum head. This motor was basically a knockoff of the gasoline motor. Many early diesels failed because a corner broke off the engine block due to poor head bolt thread engineering. The Volkswagen diesels also had problems with premature block wear caused by the higher piston side forces. This came from high rod angles resulting from a short stroke, as the block was the same height as the gasoline version. Many early diesel engines eventually developed headgasket seepage. The glow plugs for cold starting were slow and fragile.

The piston technology that allowed the high 5400 rpm redline was courtesy of a combined engineering team from Volvo, Talbot and Renault. Early industrial diesel engines had solid steel pistons to withstand the high compression and diesel explosion, but they could only churn out 700 to 1850 rpm, not enough to run a car. The new pistons were made from aluminum, but had a center band with grooves for the piston rings of high strength multiple alloy steel to survive the combustion power.

Most manufacturers created their first diesel engines of the 70’s and 80’s by putting diesel heads on a gasser block. The result was a nation full of weak diesel engines that broke and died in short order. Heads cracked, blocks cracked and warped, proprietary injection systems failed. The American public did not fail to notice the high rate of breakdown, and the smoking, and the rattle and clatter from the engine. Most customers swore off diesels, and most manufacturers followed suit. Karmakanix was there, and already had a long history of working on diesel farm equipment, diesel trucks and tanks.

Volkswagen, however, began to improve their engines. First and foremost, the weak block and head bolts were addressed mid year in 1980. The glow plugs got faster, but not stronger. A turbocharger option began in 1983, with about 6-7 psi boost pressure. In 1986, hydraulic lifters were introduced along with a bigger oil pump. Diesel vehicles left the USA scene after 1987, but soon 1900 cc diesel engines were in production in other parts of the world. The taller motors eliminated the block wear issue, as the stroke increased by about half an inch. No American Volkswagen got the 1.9 motors, but a number of grey market imports showed up. The 1.9 became a standard for engine replacement, especially in the Vanagons who sorely needed the power increase.

The VW diesel engine history began with the 77 Rabbit, and just a handful of 1983 Rabbit turbo diesels were produced. Turbo diesels were offered in Jettas in 83 and 84. The 85 through 87 Jettas had 1.6 diesels, with turbo diesels in the last of the series. There are a few “grey car” 1.9 diesels from the early 90’s, but the Tdi started with the 96 Passat Tdi and has been upgraded many times through the current model year.

The Audi diesel engine history in America includes a few rare cars. The Audi Fox never got a diesel, but the twin VW Dasher got plenty of the 1.6 diesels. The 4000 series had a 1.6 diesel model, but no turbo engines. The 5000 series had an optional 2 .0 liter 5 cylinder diesel as of 1980, and a turbo diesel was offered in only the 1983 car. Audi did not produce any more diesels for the US market until the A3 Tdi that began in 2010.

Diesels have developed tremendously since the first series of the 70’s and 80’s. Gone are the days of the cardboard headgaskets, cracking blocks, and severe block wear. The smoke and rattle went away with the first of the Tdi’s in 1996. This century’s diesels have undergone three revisions. All have the fast spooling VNT variable vane turbochargers. The Golf and Jetta series up through 2003 have an external pump and injectors, and can alter the injection quantity in hundredths of a milliliter each 1/2 turn to each cylinder. In 2004 the Pump Duse gained injectors run off the camshaft with variable pressure up to 10 times the first series, making them even more efficient and powerful. The Common Rail (CR) diesels in the 2009 and later have piezo electric injectors and a host of engineering and emission control features making them cleaner than many gasoline counterparts. And the better-than-hybrid mileage will bring a smile to any wallet. We look forward to the next major change, which may add another 15-20% to the power and efficiency. For a complete and semi accurate list of VW engine history, try the Wikipedia site on VW, and the descending links and threads.

warning 32x32Quick Clue: NEVER use starting fluid in a modern diesel motor. The most common result is that it can shatter glow plugs and even break piston rings. If your diesel won’t start, fix it. Do not risk destroying it.

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