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HEMI question

R

RU482

Lifer
HEMI this HEMI that, blah blah blah

Why did the HEMI engine disappear for ~30 yrs? What was it's downfall? Could/has the technology be incorporated into 6 or 4 cylinder engines?

just curious
 
I believe that cylinder/head design advanced and incorporated the advantages of the original hemi. Today's designs are light-years ahead of the hemi of the 60's. The hemi today is basically just a brand name I think.
 
I think the technology has been around for quite some time, but they brought back the term for marketing purposes.

But then again, I have no idea.
 
Originally posted by: Heisenberg
I believe that cylinder/head design advanced and incorporated the advantages of the original hemi. Today's designs are light-years ahead of the hemi of the 60's. The hemi today is basically just a brand name I think.
Click to expand...

what he said. i was listening to car talk last week on npr and someone called in with the very same question. clik and clak basically said that there are theoretical advantages of a hemispherical cylinder/head design, and it may look great on paper (the idea being you get more even dispersion of force against the top of the cylinder during combustion due to the hemispherical cylinder/head design), but in reality, current engine designs from competing manufacturers actually can offer greater engine power/efficiency than what the daimler/chrysler hemi design actually produces. they figured sales started to slow, and so the company's marketing folks decided to bring back the hemi name. in short, it's all marketing. but then again, what isn't?
 
the hemi never disappeared just stopped being advertised during the miserly period of cars I think was when it died out.


 
Originally posted by: xEDIT409
ok, so am i understanding correctly? The new Hemi engines arent actually real Hemi's at all.
Click to expand...

not exactly. the new Hemi engines do in fact incorporate a hemispherical cylinder/head design, but it's debatable whether it offers any real world benefits over competing designs. hemi's i guess were a big deal when chrysler originally came out with the design way back when. i think they're banking on the older generation's nostalgia and memories of when the hemi design was considered a big deal, to try and increase sales.

 
The Hemi never dissapeared. Just Dodge (MOPAR) stopped marketting their engine's with the name. Most modern engine's incorporate something from the original Hemi design. Now Dodge thinks it can win back customers by using the Hemi name.
 
The Hemispherical combustion chamber design disappeared for several reasons ;

1)Very difficult to pass emissions because of the large combustion chamber surface.

2)Expensive to manufacture because of the valve angles Incorporated into the design.

3)Poor fuel efficiency, once again because of the large combustion chamber surface.
 
Originally posted by: Roger
The Hemispherical combustion chamber design disappeared for several reasons ;

1)Very difficult to pass emissions because of the large combustion chamber surface.

2)Expensive to manufacture because of the valve angles Incorporated into the design.

3)Poor fuel efficiency, once again because of the large combustion chamber surface.
Click to expand...

Which is why they had to do ALOT of R&D on the new 5.7L engine to get it to market...
 
Originally posted by: Roger
The Hemispherical combustion chamber design disappeared for several reasons ;

1)Very difficult to pass emissions because of the large combustion chamber surface.

2)Expensive to manufacture because of the valve angles Incorporated into the design.

3)Poor fuel efficiency, once again because of the large combustion chamber surface.
Click to expand...


Which is why the scuttlebutt is being heard that Chrysler is going to have a big recall coming down the pike because all those Hemis are now failing emissions testing in a very short time on the road. Massive numbers failing emissions, esp. in the strict states like VA, CA, NY......
 
I love the HEMI, new and old.. why? cause when the word HEMI is mentioned.. people immediately think MOPAR... and being a MOPAR nut, that makes me feel good about it 🙂
 
The 'Hemi' that is the reason that people know the word 'Hemi' is the 426 Hemi. It was somewhat exotic (for the day), expensive, and relatively rare. And it made LOTS of power.

The new 'Hemi' is no longer exotic or expensive, and it's as common as cat shiat. It's just a nameplate now......🙁



JC
Mopar guy
 
Originally posted by: JC
The 'Hemi' that is the reason that people know the word 'Hemi' is the 426 Hemi. It was somewhat exotic (for the day), expensive, and relatively rare. And it made LOTS of power.

The new 'Hemi' is no longer exotic or expensive, and it's as common as cat shiat. It's just a nameplate now......🙁

JC
Mopar guy
Click to expand...

This was an interesting tidbit from just a google look....
In context, it is. Now, admittedly Chrysler was rather sketchy about rating the hemi, and I've seen about a dozen different figures - but comparing this to other MOPARS of similar vintage the point remains:

413 wedge: 470ft/lbs @ *3800* RPM, 365HP @ 5300 RPM.
426 wedge: 470ft/lbs @ 4800 RPM, 365HP @ 5800 RPM
426 hemi: 425ft/lbs @ 4800 RPM, 475HP @ 6300 RPM
(gleaned from OoooLD magazine reprints in "MOPAR Performance")

On a relative scale, the hemi does pretty badly. It wasn't *designed* for LOW RPM torque: it was designed for NASCAR and the drag strip. So, if you want to compare "race" motors, this is pretty fair - even 'tho MOPAR didn't HAVE a car equivalent to the race-built Porsche 917. Now, if we're "bench racing," let's put it into context: 426 hemi, turboed and race prepped. I've seen cars like that. 1200hp would be a walk in the park.
Click to expand...

I know the hemi is rather specialized for application as is the pent roof (which is sort of similar in design).

Å



 
Originally posted by: redly1
HEMI this HEMI that, blah blah blah

Why did the HEMI engine disappear for ~30 yrs? What was it's downfall? Could/has the technology be incorporated into 6 or 4 cylinder engines?

just curious
Click to expand...

Emissions killed it basically. It could not be made to run clean enough at that time.

 
Originally posted by: Roger
The Hemispherical combustion chamber design disappeared for several reasons ;

1)Very difficult to pass emissions because of the large combustion chamber surface.

2)Expensive to manufacture because of the valve angles Incorporated into the design.

3)Poor fuel efficiency, once again because of the large combustion chamber surface.
Click to expand...
Don't forgot slow flame propogation which required advanced timing.

EDIT: More... more... more... booom!
 
They went from flat heads to hemi heads and did a helluva lot better in the past. But, today's engines have come a LONG ways since the 60's and 70's, so the hemi doesnt have the advantage it once did. If an advantage at all.
 
Originally posted by: alkemyst
the hemi never disappeared just stopped being advertised during the miserly period of cars I think was when it died out.
Click to expand...
I ran that through the Google translator and still came up with nothing. Could you post that again using capitol letters and punctuation in the correct places?
Just trying to understand.

 
I'm not quite sure, but doesn't the new Hemi use two spark plugs per cylinder.

IMO, any current production engine that has to use dual plugs is a sad motor.
It means a compromise in design. Aircooled m/c motor tuners would fit dual plugs to help eliminate detonation, Guzzi, Bmw, Harley, Ducati. At this point in time, dual pluging is a
throw-back...

:sun:
 
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