Chevrolet Corvair engine: Encyclopedia II - Chevrolet Corvair engine - Trivia and arcana

Chevrolet Corvair engine - Trivia and arcana

Many Corvair engine fans acquired a second life after the demise of their engines, mounted bottom side out on the outside of the wheels of Corvettes involved in road-racing, in order to pull air through the brakes and keep them cool. Lightweight and cheap, they were perfectly sized.

The single carburetor on each head of the two carburetor engine was not mounted symmetrically in the center of the intake manifold, where it might be intuitively placed, but offset from the center, between the middle and end cylinders. Although sometimes erroneously cited as an engineering error, this was in fact an example of clever attention to detail; had the carburetor been placed in the center of the manifold, the center cylinder would have received a significantly greater air/fuel charge then either end cylinder. Instead, the carburetor was situated so that the firing order required the air flow to reverse itself when filling either of the nearer cylinders, whereas the airflow to the far cylinder was merely an extension of the airflow to the center cylinder, which was just prior in the firing order. This allowed for a more balanced filling of the three cylinders, and smoother operation.

High performance parts manufacturer Edelbrock made available a set of larger bore aluminum cylinder barrels (with cast iron liners to withstand wear); when combined with their aluminum pushrods, the rate of thermal expansion of all parts of the valve train became compatible, so that solid valve lifters could be used, rather than the hydraulic lifters required by the stock cast iron cylinders. This in turn allowed the engine to run to higher rpms; in conjunction with the increased torque resulting from the increase in cylinder bore, this resulted in a substantially more powerful engine.

In addition, "stroker" crankshafts with longer stroke were quickly made available for the original engine. When Chevrolet increased the stroke of the stock engine, however, there was no longer room to increase it any further.

Immediately after the car became available with the original two carburetor engine, a number of manufacturers began to sell conversion kits for attachment of four carburetors, with either two stock carburetors, two of the ubiquitous Stromberg 97 carburetors, or a Rochester two barrel carburetor for each bank of cylinders. The means of attachment varied from simple two into one adapters, to machining off the entire top surface of the intake manifold (cast as part of the head), enlarging the internal passages of the manifold, and attaching a new upper surface incorporating the appropriate mounting pads for the new carburetors. Similarly, aftermarket manufacturers provided several means of supercharging the original engine, including belt driven centrifugal, axial flow, or rotary vane type compressors. Chevrolet, seeing the marketing opportunity available in these aftermarket options, of course went on to offer its own four carburetor and turbocharged versions.

Adapted from the Wikipedia article "Trivia and arcana", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki