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Lou on "Car Fix" says new HEMI isn't a hemi

8K views 41 replies 27 participants last post by  R/T Bee 
#1 ·
Anyone watch this 30 min advertisement? The Lou character on "Car Fix" briefs everyone on the Challenger they are installing headers on & he says new HEMI isn't a hemi, it's more like a LS arrangement.

Where do these clowns come up with this stuff?
 
#2 ·
All,

My parts department friend at the Dodge dealer said the Chrysler engineers consulted the original design engineer of the Hemi engine (1950s) for the new Hemi engine. They actually made improvements to the piston/valve designs based on his inputs. That thing still gotta a Hemi, with some improvements. :)

Green Man
 
#5 ·
I'm not one for names only, however call my 392 anything you want. If you have a car TV show you can call it a piece of crap if you'd like. Reason is, my 392 kicks ass and I love it.
 
#6 · (Edited)
Whenever a Mopar Hemi engine gets a lot of attention, be it the Hellcat, the 392 or the 5.7 this crap gets trotted out. I know I am speaking in broad terms but generally I have found that it's the people who feel threatened, personally for some reason, by new engines. They seem to follow in the following categories:
1: Chevrolet or Ford brand loyalists and fanatics.

2: First and second generation Hemi owners who are offended that an affordable Hemi engine is available to the general public and can buy into the "elite".

3: Technological dinosaurs who believe that v8s should all still be related to the RB, Commando and Magnum series.

Does it shares some technical similarities to the Chevrolet LS generation of motors? Perhaps, but that isn't a bad thing, the LS motors are extremely impressive powerplants.
Do the Gen III Hemi Motors have absolutely strict hemisphere chambers? No, they have a modified hemispherical combustion chamber optimized for fuel burn and exhaust flow. They still utilize 2 plugs per cylinder and share many other design elements with the elephant motor.

The motors are an improved, updated, refined and worthy successor to the Hemi name. Is it a slavish downsizing of the 426? of course not, it would be down on power and wouldn't pass economy even if it was.

Consider this:
the new 392 for the 2015 model year is down only 20 horsepower from the LS7 with over a half liter deficit, that says a lot about the new Hemi
 
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#39 ·
I agree! The LS2 in my '05 GTO was an excellent power plant. And my buddy's gets great gas mileage with the M6. Nothing wrong with borrowing an idea here or there.

Good write up on the Hemi on allpar.com.


One quick correction..........The Elephant 426 only used one plug per cylinder.


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#7 · (Edited)
If you look at the pic,it is clearly a hemispherical combustion chamber,the Only difference is the quench area.What makes the Hemi is the canted valves and their position for better flow.I'm not sure,but just guessing,the reason for the quench is the flat top pistons.The gen 1 and 2 had dome pistons that filled the combustion chamber.
 

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#10 ·
"...and a picture is worth a thousand words." Thanks Bad Daytona.
 
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#8 ·
Are the new engines 'true', 'pure' hemispherical combustion chambers as in the 1957 392? No. But they're close enough for me and they sure aren't wedges, pent roofs or polyspheres. Plus, they have to have the same difficult valve train geometry as all the rest of the Hemi's.

Bill
 
#22 ·
Exactly!

Just so you all know, Lou is a huge Mopar fan and really knows his stuff. He came to Utah several times to ride with our Mopar club down to Mopars At the Strip in Las Vegas. Most of us already knew that what he said is true way back when the first third gen Hemi hit the market. So what? No use getting our panties in a bunch over semantics. The engine is a natural evolution from the original design.
 
#11 · (Edited)
Right. And the BMW 335i doesn't have a 3.5 engine, and the Coyote engine is not made out of wild canines.

HEMI is a name with strong heritage, marketing equity, and the current HEMIs are worthy of the name.

Ford and Chevy people: either build your own heritage, or get over it!
 
#12 · (Edited)
Here's another pic. This is an LS head.Notice that the the combustion chamber is relatively flat,and also the valves are flat,no canter.The LS heads have a side by side valve arrangement,like allmost all non Hemi heads.All Hemi heads old or new,the valves on the intake port and the exhaust ports are in alignment,straight across.How anyone can say their like an LS head is beyond me.
It's like when the B1 heads came out and started kicking tail,everyone was saying it was a copy of the BB Chevy head,when clearly the exhaust port arrangement was not similar.
 

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#15 ·

*Photo Courtesy of Andy from PWR Performance*

This is a close up of an Apache Hemi Head.


This is the definition of Hemisphere:

hemi·sphere

noun \ˈhe-mə-ˌsfir\ : a half of the Earth
: half of a sphere : half of a round object
: either of the two halves of the brain





Full Definition of HEMISPHERE

Hemisphere - Definition and More from the Free Merriam-Webster Dictionary

1
a : a half of the celestial sphere as divided into two halves by the horizon, the celestial equator, or the ecliptic
b : half of a spherical or roughly spherical body (as a planet); specifically : the northern or southern half of the earth as divided by the equator or the eastern or western half as divided by a meridian
 
#18 · (Edited)
It's a real HEMI. E... O... S..... :deadhorse:
 
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#19 ·
And another photo, this one by Toxic11, that speaks volumes.
 
#21 ·
I like the show. They did state that the motor was a serious machine that throws down some impressive power.


Sent from AutoGuide.com Free App
 
#23 ·
I think the problem was the way he went about saying it was not a true HEMI and then began spewing LS comparisons. Some architecture is similar. The heads are different.
 
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#24 ·
another "is the HEMI a true HEMI thread"?

hands up, don't shoot
 
#26 ·
Here is some information regarding the modern Hemi from allpar:

Tom Hoover one of the engineers responsible for the 426 Hemi, told Hot Rod that he had discussed the Elephant Engine’s design with new-Hemi engineers. Three of his major suggestions — raising the camshaft (to shorten the pushrods, reducing valve-train inertia and simplifying the rocker arms), using twin spark plugs, and adding squish area (to make light load/low speed efficiency better and reduce emissions) were immediately adopted.

The 2009 Hemi was extensively modified to increase both power and gas mileage. Changes included a higher compression ratio, better-flowing heads, intake, and exhaust, and an active intake manifold. This is a new technology that takes advantage of Chrysler advances in the 1960s; it switches from long runners to short runners by moving a flapper door, to switch from better torque at low engine speeds to higher horsepower as rpms rise.
The new variable valve timing system used hydraulic cam phasing, relatively simple and inexpensive. The hydraulic roller camshaft had oil passages in front to drive the cam phaser sprocket, and increase valve lift. A new piston/rod assembly had thinner walls with a stronger-alloy pin.

All the ports were redesigned, with a raised exhaust floor; the new intake valves were 2mm larger. Other upgrades were a stronger crankshaft, dual-mass crankshaft damper, floating pin pistons, new valve springs, and higher oil pump capacity. The results were better reliability and gas mileage, with more horsepower and torque at every point in the engine’s speed range.
Each cylinder has an ignition coil pack over one spark plug, and a regular plug wire connected to the other spark plug. Further, the coil pack also has a plug wire attached to it that extends to the opposite cylinder bank. Each cylinder shares a coil pack with another cylinder. Each of the two plugs on a given cylinder is fired by a separate coil. One plug has a coil directly attached, and the other is fired via an ignition wire connected to a coil located on another cylinder on the opposite bank. The benefits would be one-half the number of coils (8 vs. 16) compared to each plug having its own coil, and of course less weight.

The extra plug fires during the power stroke to more fully burn the hydrocarbons. ... the second ignition allows additional power in the down stroke while lowering the need for restrictive catalyst plates in the converter. ... [using] dual fired plugs on each cylinder allows the firing to take place closer to top dead center, and then again when the piston is on the back side of the power stroke. The extra set of spark plugs on the Hemi and on previous engines are designed to reduce NOx and ozone emissions before a catalyst is needed. They add some horsepower, but not much.
 
#28 · (Edited)
Chrysler trademarked the term "Hemi" in 1964 I believe.
Simply means other builders can't use the term "Hemi" to describe their HCC engines.
Chrysler howerver can call any engine they build a "Hemi" regardless of whether it has a HCC or not...they own the name.
Chrysler owns that name, they call it a "Hemi", so it is...period
 
#29 ·
Next post- Lou grumbled something in his sleep- Call the fire dept!!!

Lou is wrong, in as much as anybody can be wrong or right about this. The Original Hemi wasn't a perfect 180* 'hemishere' either. I for one am not willing to give up my Claim to owning a true hemi, because of the grumblings of some old know it all. In this case I'll side with Chrysler, and believe the evidence and the engineers and believe that my Hemi is, in fact as true a 'Hemi' as exisits today, over the grumblings of someone who ate a bad salad for lunch.

Wait a minute,, we must all be wrong,, because 'Lou said it'. Give me a break. :redcap:
 
#30 ·
The original 331 hemi was introduced in 1954 on Chrysler New Yorkers and it was not 100% hemispherical much like the current Hemi's. I was in HS and the garage I worked part time put one in a modified stock car we ran at the Cincinnati race bowl . Held the track record till my boss wrecked it..
 
#31 ·
Once and for all, I want to hear an esteemed engine builder go on record to say that the literal hemi shape would not even be feasible for an effective engine design, so stop expecting one to come around and stop implying there was one in the past that did.

All the Hemi name ever was, was to describe a combustion chamber with two canted valves on a spherical surface geometry. It was never about an "actual" half sphere being present. Not even the Gen 2 lived up to that standard. What the magic was really about was the air flow entering the chamber in a completely efficient manner, tangential to a smoothly spherical surface. It is elegance in the geometry. Mathematics meant it to be that way.
 
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#33 ·
I don't think the "HEMI" guys are saying or have meant to say that the top of the combustion chamber is literally "half of a sphere". I bet Willem Weertman, who was in charge of Chrysler engine design while the "Hemi" was being engineered, knew it wasn't an exact half of a sphere. It's just easier to explain the plain geometry of the shape of the head is all, at least in this guys simple mind. It seems to me some put literal descriptions on names, and a lot of times it's not the case. With the Hemi, back in the day, Im sure it was different than most other heads having some kind of curvature, best described as; hemi-spherical, or plain old hemi. Sounds better than "con-cave" head.
 
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