CNET On Cars - Car Tech 101: Hemi engines explained

A Hemi. What is it? Well, it's an engine technology, a trade name, and something of an anachronism today. CNET's Brian Cooley visits Keith Black Racing Engines in Los Angeles to see perhaps the most famous shop to ever build Hemis.

[member]

Also should be noted that Kieth Black gained a lot of success and notoriety by building really successfull 354 based early Hemis for Don Prudhomme's dragster, the Greer-Black-Prudhomme Top Fuel car was the most successful & winningest fueler team in the early to mid 60s. I have many Drag Racing magazines from this era and Kieth Black had a column on engine building. Hemi's work better than any other design with fuel (nitromethane/alcohol) and forced induction, and Kieth Black was one of the pioneers in developing Top Fuel engines.

[pseudos]

Brian so simple n cool!!!
That's why I'm in love....

[johnnysokko]

Only a Chrysler design Hemi runs in Top Fuel Dragster, and Top Fuel Funny Car. No matter what the plastic engine cover says Toyota, Ford, Chevy. It is still the exact same Chrysler Hemi. That was originally designed in 1964.



Reply

[XzTS-Roostro]

Chrysler [now Fiat Chrysler] isn't the only automobile maker that has Hemispherical engines. Other companies, like Toyota for example have one or more hemispherical engines. The HEMI brand is a registered trademark of Chrysler

[RobWillmot]

Why does the piston have to be heavier? Why not extend the air bubble inside of the piston into the hemispherical part of the piston.

[ralphvalkenhoff]

Yeah baby! I have a HEMI in my new 19 RAM and I LOVE IT!
No crappy Ford or Chevy, just good ol American V8 muscle in a legendary, time proven, horse power monster motor.

[MartyMcFlyV]

I've been a Mopar fan since 73. I have probably seen only six Hemi powered cars from 1966-70. (On the streets....not at car shows) That's one of the things that made them so special you never saw them as they were rare. Now you pull up to a stoplight and there's like three pickups or charger/challengers that say Hemi on the side. There's so many driving around it's like, 🥱yawn.
NOT saying they are not any good, just everywhere.

[mauricioalfredo]

Hemi its really about TORQUE :) and that its what you use more on street couse real hp come after 7500rpms

[Wildkat-]

The Hemi design combustion chamber lets you make more cylinder pressure than a wedge head....That's why Top Fuel & FC use BAE Hemi's ...!

[fkporsche]

Quick crash course for Hemispherical which I did not know why it's called HEMI. Now, I know a bit more of HEMI of my hellcat. Thanks for the video

[rebelsoul]

If the piston is to heavy then take more off the bottom since you added more on the top

[joshuamoore_]

I thought of two cams with half cirlces as the valves that have pin seals like a Wankel rotary engine and the spark plug in th center of the ports for the half circle shapes on the cam. One cam for intake and one from exhaust on each cylinder head. The cams turned by a timing chain or timing belt to the crankshaft. Plus a bolt down oil jacket that bolts over the camshafts with half circle valves that supplies plenty of oil over both camshafts and a port if there is a timing chain on each cylinder head out jacket. The intake half circles smaller than the exhaust. Possibly some engine blocks could be modified to have this new cylinder head camshafts half circle valve design bolted on.
Air fuel mixture
↘ ↘ ↘ ↘
🔅==|)==(|==|)==(|===
🔅===(|==|)==(|==|)==
↘ ↘ ↘ ↘
Exhaust gases
Lifterless valves

[jmc]

Its a shame the new HEMI is not even a true HEMI in the sense of design like the old ones were.

[cck]

Why this technology was not used in piston engine aircrafts?
Thanks.

[andywar]

for the love of god do a top five on plymouth Sir.those girls are so heartbreakingly pretty

[forgamztalkzz]

I have a 392 engine and I love it '

[davidrayner]

One bad feature of the Chrysler Hemi is the terrible valve-train geometry. Because the valves are so far apart, the pushrods are nothing like straight off the lifters. The solution came from Ford with the 427 SOHC engine. No lifters or pushrods. DOHC would've been even better. I ride a Yamaha XS-650 (which were made from 1969 to 1983) and they are a true hemi with SOHC, just like the 427 Ford but a lot smaller.

[machdaddy]

Do modern day Dodge engines have true hemi combustion chambers?

[TheJoeMan]

Heard that Hemi engines can't have 4 valves per cylinder.

[mike]

my 5.7 hemi only makes like 340hp.... its a 2007 but still... good torque though. about 400ft lbs