I see lots of stories here where people ask if us Cummins owners have a hemi in our truck. I'm assuming most people don't even know what a hemi is. Do many other engine makers use a hemispherical combustion chamber? I would think Chrysler isn't the only company. If a hemispherical combustion chamber is something great enough to tout, wouldn't most engines be based on that design? As far as I know, a hemispherical engine allows for better valves and more efficient operation.

The technology is so old! Why is the catchphrase thrown around so much these days as if it were a new invention?

 

Hype from TV commercial's and probably some left over memories from the 426. I think it's Hyundai or one of the bargain asian brands uses hemi designed head(s), I'm sure there are others.
I thought the new Chrysler/Dodge Hemi was actually semi-hemispherical?

 

I don't know enough about the technology, but some pictures and explanations would be great. Just because someone tells me something is great doesn't convince me.

How is the semi-hemi engine shaped and what is the advantage of that?

 

Yeah the modular 4.6 cobras used hemi heads at least until 03 if I recall correctly.

 

yeah the new ones aren't real hemi's... they're like... half-hemi... haha

 

You mean "semi-hemi"??

 

why didn't i think of that

 

IT allows for better combustion. Just like our diesels have cupped pistons so do the Hemi's. Think of the word "spherical". This is how I understand it. Both the heads and the pistons I would think would hve to be cupped. I asked a guy at church about this a year or two ago when they came back out with the Hemi. And he explained how the 426 was designed.

hope this helps!

Jon

 

I find this site very cool, spend almost as much time there as here,
http://auto.howstuffworks.com/hemi.htm

 

I like that!

 

darn near everything has a hemispherical head hondas, saturns alot of gm's mainly 4 cylinders though

 

The original Chrysler hemis were true hemis which allowed for big valves and good breathing. They were a great design for big power but are not so good for efficiency. The new "semi hemi" is a hemi with flat areas on each side of the combustion chamber that act as squish areas to add turbulence to the mix during compression, and run cleaner. Chrysler has played the word hemi for all they can. All playing on the mystic of the early design. The 426 was the final factory incarnation, but they were used in Dodge, Desoto and Chryslers from the early 50s in many different sizes. My early childhood was spent riding around in a 55 Dodge with a 277 cu. in. hemi. My dad bought the car to get that engine. Boy was he proud. Does that sound like some of us now with our CTDs

John

 

Wait, does this mean I can claim to have a Hemi? Cuz that would be way cool


I was in college when the new "Hemi" came out, and he went to schooling for engine mechanic. He would go NUTS whenever people talked about the new Hemi. He used about every 4 letter word saying how the were "fake" and not real Hemi engines. ever since, I just think of it as some big joke, and the fact that other engine makers use the same deign, but do not make a bug deal over it proves it.

My next car will be a Hyundai, and I will have Hemi stickers all over it, with license plate that says, "Yeah, it's got a Hemi."

 

Look at a flow chart of the off the shelve 5.7 hemi head and make try to make light of it... Then throw a mild cam in it and laugh... laugh because of the load of power you make on the stock tune.

I drove a SB RC Hemi powered truck for 3 years...

 

The dodge Colts in the 70s did. Also I thought all DOHC motors were.