HEMI Engine – Explained

Thanks! Share it with your friends!


What is a HEMI? Where does the name come from, and how is this engine different than other engines? This video explains the principles of a hemispherical engine; why it exists and how it differs from other cylinder head variations.

Please feel free to rate, comment, and subscribe!
And don’t forget to check out my Facebook page:

Also check out my official website: Make suggestions, participate in forums, enter for Car of the Month, learn through logically ordered lessons, read FAQs, and plan your future!


Incoming search terms:

  • engine tuners for 2018 hemi engines


Emmanuel Morales says:

So, all HEMI engines have 2 spark plugs per cylinder?

Tyler McClain says:

b18c dohc vtec

guy l says:

my 2 cents is that a true hemi design will outpower other designs however at the cost of fuel economy and tricky packaging

SetAcoustic says:

I wonder why Chrysler didn't increase the stroke to increase the compression ratio rather than add a heavier domed piston? A 4.00" stroke vs the 3.75" would have created the compression and probably resulted in less inertia.

Link1288227 says:

In your video you said the SRT8 vehicles use the 5.7 hemi…. The SRT is either a 6.1 or 6.4…

George Withrow says:

And by the way if hemi is such a bad way to build a motor why do most dragsters run only hemi motors ?

George Withrow says:

I'll take the hemi

Overcast Friday says:

Too much misinformation in this video

Ken Kord says:

Stop being so self confirming people, fact overwrites opinion. The fact remains that hemis are outdated.

4nuk8r says:

You kind of bit off a deep subject. I think I would have gone back to air cooled aluminum construction aviation piston engines for the original "why a hemi engine?".
A flat top piston has least surface area exposed to fire and so is easiest to cool. A hemi combustion chamber has the minimum area that can be constructed around a flat top piston. The fact that the valves open into free space ("unshrouded") means adequate breathing happens with the minimum lift and work done by the valvetrain – valve springs being a reliability problem then. Widespread adoption of the hemispherical combustion chamber was originally motivated by reliability concerns in lightweight aluminum engines. It's use in cast iron automobile engines was probably a sales tactic,

Nagy Szilard says:

Why is GM sticking to old technology? No overhead cams, no pentroof cylinder heads, no direct injection.

Joey Garcia says:

Two spark plugs are a little bit unusual, but not unheard of. Mazda's rotary engine (i.e. wankel) used 2 per rotor, but that's a completely different animal. A more common engine was Ford's 2.3L 4 cylinder that had 2 spark plugs. Other manufacturers did it too. Pretty much same reason why Chrysler is doing it today. Emissions and Combustion.

SaskReconAirsoft says:

Currently have a 1958 Chrysler 392 Hemi engine :D

BLVCKK 1 says:

So is this why some 4 cylinder euro cars are faster than American V8's? (not being funny. I own and love a 5.7 Hemi 🙂  )

Gleekoh Beats says:

hi if i send you a video can you help tell me what is wrong with my engine?

Akram Ghaleb says:

correction: the SRT8s don't have a 5.7 but a 6.X liter capacity

wayne parris says:

This is a political discussion, not one on mechanics. The video presenter puts forth a personal view, not an engineering one. Quality refuting posts were deleted. Carry on.

Write a comment


CommentLuv badge