What's up, DOHC? Pontiac Solstice Engine Swap?
R. J. Wetak; via CarCraft.com: We just scored a '72 Vega on eBay, and for the first time, my boy got excited over a car-what a proud day. He just turned 16 and can't drive until he's 18, which gives us two years to get it on the road. He is not ready for a 6.0L V-8, but we are drawn to a turbo 2.0L Pontiac Solstice type swap. Fabricating is not an issue, but being a V-8 addict, I am not up to speed on the interchange on the different GM four-cylinder engines, transmissions, turbos, and the like. I personally would choose a five- or six-speed, but the kid may call auto. Any tidbits of info you could supply would be great, maybe contact info for a company that caters to car crafters by supplying complete drivetrain takeout assemblies. I think this has potential to be a great experience with a very entertaining outcome.
Jeff Smith: This is uncharted territory, but let's take a stab at it. It does sound like the least intrusive approach would be to pull the complete motor and trans from a wrecked Pontiac Solstice. The first year for the Pontiac Solstice was 2006 with a base Ecotec 2.4L 16-valve four-cylinder rated at 173 hp at 5,800 and 167 lb-ft at 5,500. This is pretty tame power even for an Ecotec. The high-performance version can be found in the EXP beginning in 2007, a direct-injected 2.0L engine with an intercooled turbo that is rated at a much sportier 260 hp at 5,300 rpm and a boost-infused 260 lb-ft. That boost increase is almost 100 lb-ft or 60 percent more torque than the normally aspirated version. The transmission behind both versions is a five-speed manual gearbox with a 3.75:1 First gear with the turbo's rear axle ratio of 3.73:1. Don't make the mistake of putting an automatic behind either of these engines-that would be like draping Jessica Simpson in a burlap sack.
Issues with the turbo application may settle around fuel delivery, since the direct injection system will require a serious fuel system. But frankly, any performance engine will require a 3/8-inch minimum diameter fuel line and quality hardware. The only way this will work is to get the entire engine and trans, along with the computer, wiring harness, sensors, and anything else that will make the conversion easier. The biggest problem we see is finding an affordable package.
Another option is the all-aluminum 2.4L (146ci) or 2.3L (138ci) Olds Quad 4 engine. These motors were available in front-wheel drive (FWD) applications such as the Olds Calais, Pontiac Grand Am, and other GM FWD body styles from '87 to '95. These engines are much more plentiful and were rated at between 160 and 190 hp. These are especially cool since they are also dual-overhead-cam (DOHC) engines like the Ecotec. The hot dog Quad was the W41 engine with that code cast into the valve cover. Converting this engine to a north/south drive configuration isn't that big a deal since a company called Quad 4 Rods makes a Quad 4-specific bellhousing that will adapt to an equally plentiful GM T5 five-speed from an S-10 pickup. The bellhousing sells for $475.00, and if you insist on an automatic, the company also offers aluminum adapters to bolt several different GM automatics to the little four-cylinder. Quad 4 Rods also makes a stand-alone ignition system should you decide to convert to carburetors, as well as a header flange and stub kit that will set you up to build your own header. From a simplicity standpoint, it would probably be easier just to swap in a Quad 4 engine from a donor car complete with the ignition, injection, wiring harness, intake, and exhaust. Then you can adapt the engine to a T5 trans, and you're almost there. According to Quad 4 Rods, a complete Quad 4 with intake and exhaust manifolds, ignition, flywheel, starter, and alternator weighs 325 pounds. Compared with the '75 Cosworth Vega's dismal 110 hp, the Quad 4's 190 hp is downright impressive.
We talked with Ed Taylor, who worked with the late Jim Feuling on the Quad 4 engines back in the '90s, and he said with the log manifold (not the cute tubing intake), the H.O. camshafts, and a header, this little engine can make 200 hp-not bad for a tiny four-banger. So find one of these DOHC engines, stuff it in that Vega with a T5 behind it, and be glad you did.
Quad 4 Rods; Denver, CO; 303/287-9093; quad4rods.com, quad4forums.com