goodspeed928

928. The Original HEMI-spherical Heads
Is this true?

SMTCapeCod

Didn't the Chrysler Hemi branding effort start in the fifties? And i Think the basic concept/design goes back farther than that.
Is someone contending that the 928 design is more hemispherical than the old domestic namesakes?

Fabio421

Considering that the 928 engine wasn't developed until the 70's... I think not. The "original" hemi engines are from the muscle car erra.

hinchcliffe

No I was just kidding. I know ours are Hemispherical also. Although HEMI is a registered trade mark for Diamler/Chrysler.

How 'bout like Dr. Z says, "Yes, we do have a HEMI."

FlyingDog

928 pistons aren't domed, so they aren't really a hemi although the 16V combustion chamber is hemi-ish. Chrysler has been building Hemis (trademarked) since the 50's. The design was used in aircraft engines and maybe car engines before that. A lot of 70s and 80s Toyota 4-cyl engines are hemis. Toyota dumped it because of emissions problems similar to what rotaries have.

Bill51sdr

Yup, had a '76 Corolla with the 2T-C engine. It's a hemi! Damn good engine too!

Bus

Judging from the camshaft arrangement, I'd think the early 356 carrera four-cam engines would have hemispherical combustion chambers... though I've never looked at one apart before.

I've seen some of the rarer motorcycle engines from the 'teens and 'twenties that had external overhead valve arrangements... and some even had properly angled valves and hemisperical chambers... Imagine how it would have run if they understood flow and cam design earlier... some of them even had types of carburetors where there was just a bowl of fuel exposed to a tube of air rushing by to pull it's mixture in... we've come a long way.

Loaded

you guys ever seen a rotary motorcycle? A buddy of mine has a suzuki rotary engined MC

Malibu310

The Aston Martin had Dual Overhead Cam Hemi engines (V8)'s for quite a while, this is a picture of an old Lagonda I had, but the engines predate the 1984 car by about a decade.

fst951

Volvo was the first Pent-Hemi Head

6.0-928S

The 'old' Chrysler Hemi was 1951 to 1958. (they even made 8 factory fuel injected cars in '58 although they recalled them because electrical interference from things like neon lights made them go erratic at stoplights) The 'new' design Hemi was 1964 to 1971. The 928 is actually a 'pentroof', not a Hemi. Ya want a ride in a real Hemi stop by sometime!
Hammer

Jim bailey - 928 International

One early use of hemisperical heads.."Between 1914 and 1933 he was to sell almost half a million of the relatively low priced but high quality sleeve valve ****** Knights. .... The reason why ****** Overland was the most successful sleeve valve manufacturer lay in the enormous effort spent on redesigning the engine for minimum manufacturing costs. Although the sleeve valve engine had a number of advantages .... a hemispherical head ...." Chrysler used a hemi V-8 in 1951 copywrited the term HEMI any one can have and advertise hemispherical cylinder heads ! Any many have. the large volumn of the cylinder head means you need a domed piston for high compresion but the piston gets in the way of the spark/flame causing poor emissions whcih is why the new Hemi is twin plug with two sparks in each cylinder. And YES the early Carrera 4 cam engine is a Porsche HEMI about 1952...

Ed Hughes

911's were/are also Hemis....

Jim bailey - 928 International

Or this discussion..."In The Grand Prix Car Volume 1 by Lawrence Pomeroy, the first mention of angled valves and overhead camshafts is in his description of the 1912 3 liter Peugeot Grand Prix car, designed by a Frenchman named Henri. This was not a hemispherical chamber, it had four valves in what's known as a pent-roof chamber. So it's a level above the hemi. Hence, the inventor of the hemi, if he exists, came up with a way to reduce the potential of the overhead cam, multiple valve design.

Numerous other makes copied Peugeot and by the 1920s angled valves in crossflow heads were the norm in racing engines, both in Europe and the United States. Delage, Ballot, Bugatti, Chevrolet, Deusenberg, Frontenac, and Miller, to name just a few, were all either hemis or had pent-roof chambers with four valves per cylinder. More recent marques include Jaguar, Aston-Martin, Coventry-Climax, Coswoth, Ferrari, and Maserati....." Maybe a t-shirt proclaiming the virtues of the Pentroof design is in order

FBIII

I tyhink the Cosworth Vega was one of the first pent roofers