This page was last updated Friday, May 18, 2007

The recent rise in the popularity of the Type 4 engine lately has left a lot of people curious of what their options were in converting the Type 4 to an upright cooling system. There seems to be more well engineered conversions on the market than ever before, so it's a good time to install a Type 4 in your pride and joy.

The purpose of these conversions is to shorten the overall length of the engine, so it will fit in the engine bay or won't hang over as much as the stock cooling system. Some of these conversions allow for more cooling air, allowing you to extract more power out of the engine.

Some of these conversions require that the oil cooler be moved from inside the fan shroud to an oil cooler elsewhere. These can work fine if the car is constantly moving and a flow of air is directed to the cooler. My concern for this is for a street car in stop and go traffic. An external cooler will not have a fan constantly blowing across the cooler, and as a result the oil temperatures can rise to extreme levels. This shortcoming could be overcomed by installing a oil cooler/fan combination, in conjunction with an oil temp switch that activates the fan when the oil temp rises above a certain temperature(180 degrees F?). With this setup the oil temp could be regulated on the high side.

Let's now look at the different types of upright conversions currently available.

911 alternator

For many of years, conventional wisdom believed that utilizing the cooling fan from a Porsche 911 engine was the key to the best cooling setup. On the surface, it was an obvious conclusion: this fan cooled everything from a 2.0L to a 3.6L flat 6 air cooled engine, so it could definitely cool a hot Type 4 four cylinder. It wasn't until 2003 that we found out for a street car that the 911 fan wasn't the "best" option. The 911 fan is also the current fashion trend, as it was popularized by the Kafer Cup racers.

Due to the abundance of information on this conversion, check out this mytech article on the 911 fan conversions available for the Type 4.

Type 1 alternator

Probably the most obvious conversion utilizes the Type 1 alternator (or generator) and it's matching fan. These pieces, that are probably in the average enthusiasts's garage already, are familiar to you and are reasonably priced. This assembly can cool anything from a stock 1.7 on up to a large cc fire burner. The shroud design itself is what makes this assembly effective.

There are many options in this category, so I've created a tech article on the Type 1 alternator conversion.

Horizontal fan

A third option is the horizontal fan. This places the fan laying on top of the engine. Riechert Tuning of Germany offers this conversion(it's on the bottom of the page) utilizing the 911 fan and alternator.

The problem with the horizontal fan conversion is that the twisting of the fan belt makes it susceptible to throwing fan belts. The 90 degree turn necessary to reach the pulley for the fan is the weakness and makes this conversion not as common. This weakness is inherent. I haven't received any reports on people who've run this conversion, so I can only speak from speculation.

After reading my thoughts on the horizontal fan conversion, the late Joe Locicero of Oregon Performance Products sent me this information in an email. The Chevrolet Corvair, built from 1960-1969, featured an air cooled engine and a horizontal fan, and it had the problem I described. Here's Joe's comment:

The belt throwing problem on the Chevrolet Corvair was rectified some time back by a Chevy Agency in Conneticut (Zink Chevrolet, I think). They sold custom bodied Corvairs and also did some racing. The problem is that the belt elongates in proportion to the amount it streches from the resistance (load) pulley to the power source (crank pulley). The greater the length of the belt, the longer it streches. The elongation happens on the right side on the Chev Corvair (idler pulley side) and on the left side on the Reichert set up since VW's rotates clockwise. The elongated slack side of the belt rises out of the "fixed" pulley groove and the belt is thrown. A new belt is a temporary fix until the fiber plies start to separate. The lighter magnesium fan on the Corvair reduced the fan throwing episodes, but in time as the belt got older, it would start throwing again. A simple spring loaded idler pulley will temporarily "follow" the belt as the belt elongates.and retains the belt in the pulley groove. I personally tried it on my Corvair Turbo 150 rail in 1970 after I heard about it. Very simple fix. Never threw a belt after that. I'm not sure what Reichert is doing or has done about the problem.

The horizontal fan conversion isn't very popular, so the information about it is just as scarce. If you've run a horizontal can conversion on a Type 4 engine, please feel free to contact me and share your experiences.

I want to thank the late Joe Locicero of Oregon Performance Products for sharing his vast knowledge.