Stupid question time

[Greg Myers]

HEMI, short for HEMIspherical, the shape of the combustion chamber. 

[Harry P.]

I'm glad he asked it here Harry. I knew the answer to this one, but I'm sure there others out who didn't. There are times where questions are asked here that I too have wondered about. Questions not important enough for me put a lot of time into and wanting to do a real research for the answer.

Go to google.com.

Type in OEM.

Bang. Answer.

Elapsed time? Maybe five seconds? Not exactly a "whole lot of time" put into research.

Don't misunderstand me... I have no problem with people asking questions here. In fact, I encourage it. But the OP said that he was "wracking his brain" trying to figure out the answer. I just let him know that the answer was literally seconds away.

[gtx6970]

Here's a little food for thought. A 426 Hemi is NOT a true Hemi . Look at the cutaway pic shown. and compare it to a similar view of a 392 Hemi .

The 426 piston one side of the piston is taller, and the spark plug isn't dead dead center of the combustion chamber, plus its canted slightly ,,,,,,. On a 392 It's straight up and down and in line with the piston stroke

[Ace-Garageguy]

Here's a little food for thought. A 426 Hemi is NOT a true Hemi . Look at the cutaway pic shown. and compare it to a similar view of a 392 Hemi .

The 426 piston one side of the piston is taller, and the spark plug isn't dead dead center of the combustion chamber, plus its canted slightly ,,,,,,. On a 392 It's straight up and down and in line with the piston stroke

People want to argue that the current Mopar engines labeled as "Hemi" aren't "true hemis" either. The debate rages, but it's largely academic and semantic.

This is a classic "hemi" combustion chamber...opposed valves, top of the chamber looks kinda like half of a tennis ball.     

It uses a piston that looks more or less like this...   ...and isn't really very good from an emissions standpoint today for a number of reasons.

The Gen III Mopar Hemi chamber looks like this...      ...with the edges pinched somewhat and two plugs to help with complete combustion.

The "hemi" combustion chamber idea has been around a long time. This is an old Harley. A lot of old aircraft radials used something similar.   

                                                                                           

It's essentially the same basic layout, and you can have a 4-valve "hemi" too (or close)...   

You can argue 'til you're green about what constitutes a "true" hemi, but for an understanding of what's what and why it makes a difference (and the only differences that matter are numbers on the dyno, or the emissions and fuel economy figures), you need to understand combustion chamber design and its evolution over the years.  

There are many books and online articles on the subject. 

 

Edited March 11, 2016 by Ace-Garageguy

[Longbox55]

Another hemi head example, this on is a a GMC 270 inline 6 cylinder from the '40s/'50s.

Note that it isn't a crossflow head, the intake and exhaust ports are all on the left hand side of the head.

[JollySipper]

Move Over Plymouths Are Racing......

Has Engine Muscle Inside.............. 

[Sport Suburban]

I like to research this kind of stuff and the term Mopar originally was a adapted the parts like by Chrysler. It was taken from MOtor PARts! 

Another interesting one is AC Delco. AC came from the AC spark plug company and was kept when they merged with Delco. Creating AC Delco as it stands today. AC actually stands for Albert Champion! Yes the Albert Champion that created Champion spark plug company and lost control of his company to investors and was booted out. Then he started the AC spark plug company.

[Belugawrx]

I like to research this kind of stuff and the term Mopar originally was a adapted the parts like by Chrysler. It was taken from MOtor PARts! 

Another interesting one is AC Delco. AC came from the AC spark plug company and was kept when they merged with Delco. Creating AC Delco as it stands today. AC actually stands for Albert Champion! Yes the Albert Champion that created Champion spark plug company and lost control of his company to investors and was booted out. Then he started the AC spark plug company.

Very Interesting

[peteski]

Go to google.com.

Type in OEM.

Bang. Answer.

Elapsed time? Maybe five seconds? Not exactly a "whole lot of time" put into research.

Don't misunderstand me... I have no problem with people asking questions here. In fact, I encourage it. But the OP said that he was "wracking his brain" trying to figure out the answer. I just let him know that the answer was literally seconds away.

I guess nobody dared to click on the link I posted on the first page of this thread.

[Greg Myers]

WOW! MR> Peteski and I must addres you as such, myself being a mer mortal in the relm of computer genius. That was great. 

[Roadrunner]

On one of the other forums I belong to, I really had some fun. I asked what SWMBO meant (I really had no idea). When it was explained to me, I said "Oh, you mean guys that let women boss them around". Man, did that stir up some conversation!

[DanR]

Always remember the wise words of Mr. Garrison as he addressed his South Park elementary school class:

"Remember children, there are no stupid questions, just stupid people."

 

 

[Greg Myers]

I have a sign I had hanging in my shop class.

" Don't be afraid to ask stupid questions. They're easier to answer than the hard ones."  

[peteski]

WOW! MR> Peteski and I must addres you as such, myself being a mer mortal in the relm of computer genius. That was great. 

You too can become that computer genius. Just go to http://lmgtfy.com/ (easy to remember URL: LetMeGoogleThatForYou.com) then do you thing. Then click "shorten" button and copy the URL above the button.