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Quad 4 motor
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Posted by: Egmexpedition_99

Hello folks, can someone briefli explain how does a quad 4 motor works ? is the one that has 4 cil and 8 plugs right ???

Egm

Posted by: Grape Ape

4 cylinders and 8 plugs isn't a Quad4. That's a "dual plug" engine. The Quad4 was a GM nightmare used first, as I remember, in the Pontiac Grand Am and Oldsmobile Cutlass(Calais). This engine simply has multiple valves as far as the name goes and dual overhead camshafts(DOHC). They were quite powerful for their time and displacement. Problem was, they had problems staying together in the long run. There's one in a Grand Am in my back yard now. Hasn't run right(if at all) since 1999. Heads apparently like to warp/crack. Typical of these engines just about 100,000 miles. Getting repair or replacement parts is difficult and expensive.

Posted by: Mr. P

The Quad Four was an engine GM designed but never bothered to develop or perfect. It was quite powerful, but they couldn't sell them. Smog regulations choked the power down too.

Texsid Alutek from Italy, a division of Fiat, joint ventured with the State of Tennessee and built a plant in Dickson, TN to produce cylinder heads for the Quad 4. At the time GM was experiencing about 10% waste in their casting facilities, and the Italians were a long time master of aluminum casting, so they gauranteed less than 1% waste or they would pay. It worked. If you look closely on many cylinder heads these days, for Ford, GM and Chrysler, you'll see the three tier pyramid shape of the Texsid logo.

The Vega GT used a predecessor of the Quad 4, and later the Olds Quad 4 came out and was fairly successful. The Vega GT was never a very fast car, due to weight and smog problems. The motor got it's name from simply having a 4-valve cylinder head with double overhead camshafts, which is quite common these days. I understand there were lots of performance parts available for these motors, and in racing form they should have been fast but little motors.

By European standards, they're nothing approaching the exotic. The development of this motor lead to the 4-cam V8 motors GM developed that all have 4-valves per cylinder, and all of them have one spark plug per cylinder.

Mr. P

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