Chrysler brought the HEMI engine for sale back in 2003, with the debut of the newest generation of Ram pickups. Now it’s in the Chrysler 300C and Dodge Magnum, and soon will be found in some of the Jeeps.
Like its legendary predecessors, the new HEMI’s two valves per cylinder are operated by pushrods. As in previous Hemis, intake and exhaust valves for each bank of cylinders are at an angle in the head and have their own rocker arms. In this era, when dual overhead cams and four-valve heads are found in many cars, especially economy cars, why did Chrysler go for such a seemingly ‘cave man design’? All things considered, even though it’s more complex than a typical pushrod engine with its two valves per cylinder in line with the crankshaft and using one set of rockers, it’s simpler and more cost-effective than an overhead-cam engine.
It’s design produces equivalent power to an overhead cam engine, but costs less to build. Each cylinder in a 5.7-liter V8 is large enough (.71 liters each) and the revs are low enough that the two-valve hemi design works perfectly for modern automobiles. Hemis can run well on lower octane fuel than some other designs, and Chrysler’s newest is satisfied with mid-range gasoline.
Don’t think that the new HEMI is lacking in contemporary technology. It’s the first variable-displacement engine to make it to production. The Multi-Displacement System” (MDS) is standard on all HEMIs in 2005 Chrysler 300Cs, Dodge Magnums, and the Jeep Grand Cherokee.
Simply put, the MDS works by deactivating the lifters in four cylinders, keeping their valves closed. No fuel is injected at that time, increasing fuel economy, and no air is pumped, decreasing energy and therefore power that would be lost pumping air. Use of electronic throttle control, electronic fuel injection, sophisticated electronically-controlled hydraulic lifters, and control algorithms makes it all work quickly and seamlessly.
It takes only 40 milliseconds (0.040 seconds) to switch between four-cylinder and eight-cylinder modes, and the process can’t be felt. We had the opportunity to repair a Chrysler 300C with the MDS system. We had attached a scanner tool first to go on a diagnostic test drive that included city streets and freeway driving, with full-throttle acceleration needed for freeway merging. I never noticed any change in the engine’s response or power ,there was never any lack of power and I was surprised when I saw the graph of operation after the data was downloaded to a laptop. The HEMI was very active, switching between modes constantly, not just occasionally.
And if 340 horsepower isn’t enough, Chrysler has released the 300C SRT-8. Its a HEMI also and has been enlarged to 6.1 liters and compression increased, to make 425 horsepower and 420 lb-ft of torque. A sport-tuned suspension and Brembo four-piston brake calipers will be hidden under slightly-modified bodywork. With a 0-60 time in the low 5-second range and a quarter-mile time in the high 13s, this looks to be the hottest HEMI since the glory days of the muscle car era.
The new generation of HEMI engines are very plentiful, being used in applications never thought to be practical with the old HEMI engines. Perhaps it does not have the animalistic tendencies of it’s predecessor, but it has good street manners. Meaning it runs great on the street. For more information on purchasing a HEMI for sale in any form or generation call GotEngines.com @ 1-877-267-0664.
As a full line engine supplier, our vast networks allow us access to the lowest mileage used HEMI engines from any generation from top notch scrap or recycling yards all over the country. If you desire a rebuilt engine, we have specialty rebuilders of older engines for sale, as well as access to the most thorough and modern engine rebuild companies on the market.
