WP64 Posted December 6, 2007 Report Share Posted December 6, 2007 With all the hype developing around the new 08 Dodge "Hemi" Challenger, I'm sitting here spinning my wheels trying to understand what makes a hemi engine a hemi??? As I was taught, it's the design of the cylinder head chamber (or pocket), it has to be a hemispherical shape which , as I understand it, means even and consentrically shaped in all aspects AND the spark plug is located at the top of the chamber. With that said, when I look at our (GT500) cylinder heads what do I see? Even, concentrically shaped cylinder head chambers with the spark plug at the top of the chamber...Isn't this a "Hemi" design??? Please help me out here, are our engines NOT a hemi because we have Ford motors and the "Hemi" engine is a Dodge thing, or is there more to a Hemi engine than what I described above??? What do you guys think? WP Link to comment Share on other sites More sharing options...
DDT Posted December 6, 2007 Report Share Posted December 6, 2007 With all the hype developing around the new 08 Dodge "Hemi" Challenger, I'm sitting here spinning my wheels trying to understand what makes a hemi engine a hemi??? As I was taught, it's the design of the cylinder head chamber (or pocket), it has to be a hemispherical shape which , as I understand it, means even and consentrically shaped in all aspects AND the spark plug is located at the top of the chamber. With that said, when I look at our (GT500) cylinder heads what do I see? Even, concentrically shaped cylinder head chambers with the spark plug at the top of the chamber...Isn't this a "Hemi" design??? Please help me out here, are our engines NOT a hemi because we have Ford motors and the "Hemi" engine is a Dodge thing, or is there more to a Hemi engine than what I described above??? What do you guys think? WP I think Hemi is a Dodge Pattent Phrase and you described the simularities of the design accurately......... Link to comment Share on other sites More sharing options...
07alloyGT Posted December 6, 2007 Report Share Posted December 6, 2007 IMO, it looks like mainly a copyrighted thing more than anything. According to the article linked below, "One thing that a hemispherical head will never have is four valves per cylinder. The valve angles would be so crazy that the head would be nearly impossible to design." So, I would gather that the GT500 has a pentroof hemi head as opposed to a true hemi head. http://auto.howstuffworks.com/hemi.htm Link to comment Share on other sites More sharing options...
WP64 Posted December 6, 2007 Author Report Share Posted December 6, 2007 Why ? Do you want to put one of those stickers on your bumper? "Yeah, it's got a Hemi" Well, no... Where do you get those stickers anyway? I'd like to put one on my Nash Rambler Link to comment Share on other sites More sharing options...
carnut Posted December 6, 2007 Report Share Posted December 6, 2007 Hemi schmemi, Dodge sucks. Link to comment Share on other sites More sharing options...
WP64 Posted December 6, 2007 Author Report Share Posted December 6, 2007 Hemi schmemi, Dodge sucks. You're preaching to the choir here carnut... BTW Chevy sucks too PS Shouldn't that be "Hemi schemi"? Link to comment Share on other sites More sharing options...
ilmor Posted December 6, 2007 Report Share Posted December 6, 2007 I think I read somewhere the the current "Hemi" is not a true "Hemi" in the sense that the original one was. It's really just "badge engineering". I could be completely wrong, of course. Link to comment Share on other sites More sharing options...
carnut Posted December 6, 2007 Report Share Posted December 6, 2007 You're preaching to the choir here carnut... BTW Chevy sucks too Link to comment Share on other sites More sharing options...
Alloy Dave Posted December 6, 2007 Report Share Posted December 6, 2007 With all the hype developing around the new 08 Dodge "Hemi" Challenger, I'm sitting here spinning my wheels trying to understand what makes a hemi engine a hemi??? As I was taught, it's the design of the cylinder head chamber (or pocket), it has to be a hemispherical shape which , as I understand it, means even and consentrically shaped in all aspects AND the spark plug is located at the top of the chamber. With that said, when I look at our (GT500) cylinder heads what do I see? Even, concentrically shaped cylinder head chambers with the spark plug at the top of the chamber...Isn't this a "Hemi" design??? Please help me out here, are our engines NOT a hemi because we have Ford motors and the "Hemi" engine is a Dodge thing, or is there more to a Hemi engine than what I described above??? What do you guys think? WP I think you are correct about the description of Hemi....but my guess is that even if Ford chamber looks like a hemi...they'd never call it that or sales would drop by 80%. Link to comment Share on other sites More sharing options...
DDT Posted December 6, 2007 Report Share Posted December 6, 2007 I think you are correct about the description of Hemi....but my guess is that even if Ford chamber looks like a hemi...they'd never call it that or sales would drop by 80%. Sometimes you call it right on........... Link to comment Share on other sites More sharing options...
srk1959 Posted December 6, 2007 Report Share Posted December 6, 2007 IMO, it looks like mainly a copyrighted thing more than anything. According to the article linked below, "One thing that a hemispherical head will never have is four valves per cylinder. The valve angles would be so crazy that the head would be nearly impossible to design." So, I would gather that the GT500 has a pentroof hemi head as opposed to a true hemi head. http://auto.howstuffworks.com/hemi.htm 07alloyGt.....you win the prize!!!! The new Mopar Hemi is only called a Hemi because Chrysler or whoever they are now own the trademark.....even the original Hemi's were not true hemi's due to the placement of the the exhaust valve so they could fit the engines in the street car chassis....the pentroof is a much superior chamber design for our purposes, it allows 4 valves per cylinder which will rev higher and flow more than 2 large valves....and you don't need a large cylinder bore to have lots of intake flow.....I still own 2 original "Hemi's" and big bore = big valves...Heavy.. 4.56" bore 2.4" Intake..I haven't checked but I bet our 4 valves don't flow much less even with the small bore on the 5.4...just have to love technology...that's why I sold 2 Hemi's to buy 2 GT500's!!!! Link to comment Share on other sites More sharing options...
DDT Posted December 6, 2007 Report Share Posted December 6, 2007 You're preaching to the choir here carnut... BTW Chevy sucks too PS Shouldn't that be "Hemi schemi"? What about all the FORD HOT RODS with CHEVY ENGINES????????????? Link to comment Share on other sites More sharing options...
mciarochi Posted December 6, 2007 Report Share Posted December 6, 2007 I believe the early "Boss" head was similar in design to the hemi head. Probably all in the trademark. I will NOT put a Dodge sticker on my car, you've GOT to be loco... The reason there are Chevy engines in Ford hot rods is because small block chevys are the most affordable engines to modify, and every hod rod is nothing but wall-to-wall modified. Doesn't make them better, just cheaper, and therefore easier to maintain and sell. Link to comment Share on other sites More sharing options...
Blue Oval Posted December 12, 2007 Report Share Posted December 12, 2007 What about all the FORD HOT RODS with CHEVY ENGINES????????????? It's because they are cheap, easy to come by & easy to retrofit. I think it has a lot to do with the oil pan sump being easier to deal with on a Chevy. Maybe some Chevy guys actually wanted a car with some class & still had boat anchors laying around at the same time. This is a Ford site, and although it is rare, you have to expect some of the Chevy bashing once in a while. Link to comment Share on other sites More sharing options...
mastersmech1 Posted December 12, 2007 Report Share Posted December 12, 2007 A friend of mine had a Hemi. He had it removed and found it hard to sit down. He had to use a donut pillow to make it bearable. Link to comment Share on other sites More sharing options...
svtbird91 Posted December 12, 2007 Report Share Posted December 12, 2007 A friend of mine had a Hemi. He had it removed and found it hard to sit down. He had to use a donut pillow to make it bearable. Link to comment Share on other sites More sharing options...
svtbird91 Posted December 12, 2007 Report Share Posted December 12, 2007 What about all the FORD HOT RODS with CHEVY ENGINES????????????? Worst thing you could do to a Ford hot rod is ruin it by putting a Chevy engine in it.... real men don't where bow ties. Link to comment Share on other sites More sharing options...
DDT Posted December 12, 2007 Report Share Posted December 12, 2007 It's because they are cheap, easy to come by & easy to retrofit. I think it has a lot to do with the oil pan sump being easier to deal with on a Chevy. Maybe some Chevy guys actually wanted a car with some class & still had boat anchors laying around at the same time. This is a Ford site, and although it is rare, you have to expect some of the Chevy bashing once in a while. Ok........ And I thaught it was because the Half Breed owners liked the phrase; "BUILT FORD TOUGH WITH CHEVY STUFF"............. Link to comment Share on other sites More sharing options...
Son of GT Posted December 12, 2007 Report Share Posted December 12, 2007 You want a Ford Hemi? HERE's your Ford Hemi: Not practical for the street, but it is a Hemi. Link to comment Share on other sites More sharing options...
svtkeith Posted December 13, 2007 Report Share Posted December 13, 2007 I might be wrong here but didn't Ford make a 427ci double overhead cam engine in the mid to late 60's and it was dubbed "a Semi-Hemi" Link to comment Share on other sites More sharing options...
Son of GT Posted December 13, 2007 Report Share Posted December 13, 2007 I might be wrong here but didn't Ford make a 427ci double overhead cam engine in the mid to late 60's and it was dubbed "a Semi-Hemi" Yes, you're right about that. And there were also the drag racers who installed Ardun Hemi heads on big block Fords too, but of course those were not factory Hemi's. Link to comment Share on other sites More sharing options...
DDT Posted December 13, 2007 Report Share Posted December 13, 2007 Yes, you're right about that. And there were also the drag racers who installed Ardun Hemi heads on big block Fords too, but of course those were not factory Hemi's. HALF BREEDS! Link to comment Share on other sites More sharing options...
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