Seen lots of stuff about Chrysler bringing back the "hemi" enignes. What is the specific component or technology that defines an engine as a "hemi"

Probably a dumb question, but I had to ask.

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Dave

1995 S320

The combustion chambers in the head are hemispherically shaped.

This design apparently is optimum for increased hp.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

From Chrysler's perspective, the hemi was their equivalent of the Cosworth-Ford V-8 in Formula 1. In both NASCAR and NHRA, the Dodge and Plymouth hemi powered cars were the ones to beat. That translated to the brand's image as a powerhouse in street cars like the Barracuda, Roadrunner and the forerunner of the aerodynamics of the Mercedes Evolution II, the Superbird.

Suginami is right.

The technology has been around for decades (Chrysler was putting hemis in cars back on the 50's). But, they moved away from them in the late 50s/early 60s as they were expensive to produce, compared to a normal setup.

They became famous in the mid-sixties with the introduction of the 426 Hemi....the rest is history.

Here's some info on the Hemi:
http://www.allpar.com/mopar/hemi/ardun.html

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Glen Tokuhara
Beauty & the Beast and the wagon that could!

I think the orig hemi idea was for a massively powerful gasoline powered truck engine for short-haul small trucks. Some wise-guy engineer in the Plymouth (?) division said, "I think we an fit that sucker into a car" So they tried it in what used to be a DeSoto (?) first and it worked for giving giant car made of 3/16th steel, iron and leather at about 100 mph.

Then other folks started putting it in smaller, lighter cars. Then it went to a drag strip and left flathead's and small block GM's and Fords second behind. Chrysler got the cheese as the producers of the muscle in the first "muscle" cars.

Cevy tried to match them with a small but high pwr/wt ratio'd 409 that had a weak crank shaft. Ford eventually got the 427(?) from which some great super performance engines were developed. Pontiac (?) came out with a 426(?) on the LeMans (?) chassis with limited-slip differential and called it the GTO and 4-doored it into the 2+2 piece of overweighted, understeared ballistic steel, 2+2. I'll bet every one of them is stuck in a tree or hillside. Plymouth stuck the hemi into a lighter car with a huge carb made famous on "Dukes of Hazard".

None of those cars could go around a corner at speed but nothing could beat them on straight road.

B

So can we call the Porsche 911 a hemi?

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You don't need a weatherman to know which way the wind blows - Robert A. Zimmerman

This is what I think of whenever I hear that little boy on the Durango commecial say "hemi" not some truck with a DVD player

so what would be a draw back of a hemi?

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198? 300D ???K - Future DD
1989 300TE 285K - traded in '12
1984 300SD 186K - Sold in 08
1978 300SD 330K - Died in 05

The sons of Mohammed love a hemi.

ECONOMY 6 mpg

So true!

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Learn as though you will live forever.
-Ancient Hindu Proverb
(Are there any modern ones?)

1998 E320 Blk\Blk
1995 BMW 530i (bad engine) sold
1989 BMW 535i sold after 170,000 fun miles
1996 Lincoln Town Car (6 passenger land barge, still smooth and quiet at 130,000 miles, make me an offer!)

The downside is COST. A true hemis has the heads machined to a hemisperical shape. These are not merely crossflow heads-i.e. the intake and exhaust valves on opposite sides of the heads--that increases effieciency ( Peugeot did that back around 1911--and the design dominated Indianapolis for decades, ( known as Offenhauser)). Chrylser and Ford both did wedge heads--similar but w/o the hemisperical shape--thats what is so costly.

Yeah, but that was out of a muscle car from the '60's...IIRC, the wedge-head V-8's from that era were getting roughly the same fuel economy.

Actually, theoretically, a Hemi would get somewhat better fuel economy, since the fuel's burned somewhat more efficiently (same reason they make more power)...

I think Mike Fowler hit the nail right on the head; they're more expensive to manufacture...

A 426 Hemi is the only g@$$er that I'm willing to own...

If I remember what I've read correctly, the hemispherical combustion chamber is actually not the shape that produces the most power, but it's probably cheaper to make (and possibly more adaptable to ordinary driving?) than one complex enough that it is.

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Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

I heard the hemis were finicky engines... tough to get to work right but once you had them tuned..Oh Boy!

Any truth there?