What's the fuss over the Hemis that Dodge is producing.
I do like the new body style that Dodge is making now. Anyone in here own one ?
If so, how do you like them ?


Fenster.

Historically, the hemispherical design has resulted in more power...

Of course, it's 'muscle trucks' (UGH) instead of 'muscle cars' now...

the hemi has ALWAYS made power, POWER=HEMI, or HEMI=POWER lol, the boss 429 ford made back in like 1969-1970 made power because of the similar "HEMI" like design fords was known as a semi-hemi, plain and simple, hemi meens power

The Mopar 426 Hemi engine was the most desirable ever built.

Look at it this way. The area of a circle is a function of diameter this will give a certain square inches of piston top for a certain diameter.

Now if you take that same piston and curve the top round like a half a ball, now you have increased the surface area. Now you have more square inches of surface for the explosion of the gasoline to push against. More square inches same pounds of pressure per square inch and you have more push per piston diameter with a rounded top piston.

The new hemis are allright...good power.

But..

they are NOTHING like the ALL MIGHTY 426 Hemi!!!

they rated it at 425HP...but that was just to keep the insurance companys off their back. It was most likely closer to 500. STOCK!!! Imagine that with some preformance parts and a blower!!!

What I would give for a 69 Charger R/T with a Munce 4 speed and a blown 426hemi!

BTW..you can get it as a crate motor now..to the tune of $12,000. Dodge started making them again to help with people who had the old hemis and needed new heads, etc.

Tek said:



Tek, the Muncie 4 speed was a GM tranny.  Chrysler used a very bulletproof in house tranny called a New Process.

And yes, the 426 was the ultimate factory engine ever produced.

In fact, EVERY Top Fuel Funny Car and TF Dragster, as well as almost ALL Top Alcohol cars are still running direct decendents of the mighty 426, and I mean "direct"!!

Up untill a few years ago, the aluminum versions of the 426 still had the original motor mount ears cast into them.

Also helping, was the way the valves were positioned and the shape combustion chamber which was conducive to large diameter intake/exhaust valves, which made it easier to get the air/fuel mix in and out in a hurry.

You earn something new every day!

The Hemi was definatly awesome! I think a engine like that would require constant tinkering..but to have that much power a foot push away.

I would have to take some race driving lessons first!

Additionally, the location of the spark plug, at the very top of the combustion chamber, was a big advantage. First, since it's directly in between the valves, there is lots of A/F mixture turbulence around the plug, which makes for more reliable and complete ignition and combustion. Also, the flame front created by the top mounted plug travels directly downward towards the piston, as opposed to across the chamber from one side to the other. This allows more power for obvious reasons, but also makes the engine somewhat resistant to detonation.


The original 426 Hemi's also had the advantage of being based on the RB series of engines (413, 426, 440) which means they had extra long connecting rods, VERY stout blocks, and a distributor that mounts to the front of the engine, making spark timing more accurate (no problems with camshaft flexing causing erratic timing). Also the main bearing caps on the 426's were cross-bolted, making for an almost bulletproof lower end.

I haven't checked out the new ones yet so I don't know anything about the structural features (since I'm no longer racing), but I'm thinking about buying a new truck, and the Hemi is part of why I'm thinking of buying a full sized truck instead of a smaller model like a Dakota. If they would offer the Hemi in a Dakota, I'd buy one tomorrow.

While the Mopar Hemi is the ultimate buildable motor I would not say it was the ultimate crate motor out of the factory. I would argue the 427 SOHC hemi headed motor as the ultimate motor to come out of Detroit. 615 horsepower with single carb. and 675 with dual carbs at 7500 rpm.

For the record, 427 medium risers ran with Mopar Hemis in Nascar while high risers and tunnel ports ran well in drag racing. High risers and tunnel ports would have eatten up Hemis in Nascar.

I think the coolest time in drag racing was the 60's when Ford and Chrysler were fighting it out in A/FX classes.

That is not possible, I believe one of the reasons of the hemi's  demise as a street engine is because the way the combustion chamber cooled the fuel-air mixtures too much resulted in incomplete combustion which caused hydro-carbon emissions to emitted to the atmosphere.

Ahhhhhh the 60s & 70s, those were the days of the rivalry between Ford & Chrysler.

Yes the 426 hemi was a monster, but for some reason, people credit the combustion chamber shape for the power, instead of the two giant 4 barrel carbs sitting on top of the thing...[rolleyes]

The trademark 'Hemi' is a marketing hook, pure and simple, like Ford's 'Power Stroke' or GM's "Vortec".  

yup, marketing ploy

MONDAY! MONDAY!MONDAY!..ridin' in Dodge Hemi truck!!

Yepper...slick marketing jedi trick.

Hmmmm, big block Chrysler...hmmmm  Mopar or no car!

From what I understand the early 331, 354, 392 Chrysler FirePower Hemi had a better top end than the later 426 but wasn't nearly as bullitproof on the bottom end (in stock form).  The FirePower's little brothers...Dodge Red Ram & Desoto FireDome were kinda neat also, with the Plymouth PolySphere being the redheaded stepchild of the bunch.

Also, the first American car with 1 hp per ci was [b]not[/b] the fuel injected 283 Chevy, it was the 355hp 354ci Hemi in the Chrysler 300.

The shape of the piston has NO effect on the amount of force from the pressure.  The force is simply the DIAMETER of the piston being pushed by the combustion pressure.

Hemi is just a marketing ploy.  Look at the combustion chambers of the Audi 5 valve engines.  Its as close to a hemi as possible but only because of 5 valves and a spark plug.

I read an article in "Car And Driver a few year back saying that the Cobra 427 Cobra-Jet had the most potential!  
Either way there both awsome motors.I would love to have two twin Hemi's or Cobra Jets sittin in a 50ft Cigarrete boat, then climb out of my boat into my 1969 Shelby Cobra Conv.
w/ 427, 4 speed, and race home too my double wide trailer. Life would be great. (I dont live in a trailer)

Hell Fenster I'd let you even drive them both.

The old early/mid '70s Toyota Carina my dad drove had a hemi 4cyl, & so were the old Harley Pan & Shovelhead IIRC.  The SOHC Honda 4's.....

It wasn't shit compared to the Chevrolet L88 427 (425 HP at an undisclosed RPM).


There was no 427 CJ. There was a 428 Cobra Jet that was an overhyped truck engine that wouldn't run worth a shit up next to a big block Chevy or any of the other big block Fords. It made nice torque for the full-sized Fords and Lincolns and it was marketed well, but it was lacking on the strip.

1966 Ford made a 427.  Fine motor with lot's of guts. It wasn't a Cobra.

Any of you guys that don't think the head design has anything to do with power needs to go back to school.

The 426 Hemi was banned from Nascar not because it was a inferior design but a superior design.

Tj

But they didn't exist in the 1950's and 60's when the first and second generation Chrysler Hemis were built.

Most DOHC engines have hemispherical combustion chambers. It is very difficult to build a push-rod hemispherical V8. American builders though rejected OHC designs throughout the 50's and 60's while the British/Germans/Italians embraced them. They were more expensive to build and maintain, especally as the oils needed to protect overhead camshafts for long periods of road use didn't exist then. Chrysler's coup was getting a hemispherical head while still using a pushrod valve train that could be made without fine machining or exotic metal alloys and could use the cheap, low quality motor oil that US oil companies peddeled at the time instead of Castrol which was required by the European OHC engines.

When Pontiac tried to go agains the grain and built the Tempest Sprint with a DOHC straight six it turned out to be a disaster. Its aluminum cylinder head was nothing more than a copy of Jaguars and included hemispherical combustion chambers but they were a disaster with coaking problems blocking up the oil passages to the camshafts, which then ruined the head when they starved for oil-except for those owners who also owned foreign cars and were savvy enough to put in Castrol at the first oil change.

The first engine with hemispherical combustion chambers were I think the Miller streight eight of the 1920's, that led to both the Dusenburg 8cyl and the long serving Offenhouser 4cyl racing motor. All were overhead cam designs.

Yeah..ok.  I guess the 68 1/2 Cobra Jets were a fluke at their debut in the 68 Winternationals when they destroyed their competition in super stock.  I guess Alvin Le Blanc's 69 Cobra jet is a turd while it holds SS/F and SS/G class records at 9.57 ET at 140mph or Richard Pauley's 68 Mustang that only runs a 10.51 in C/SA. Having owned quite a few Cobra Jet Mustangs I would have to say you don't have a clue what you are talking about. You should watch a NHRA race and see how many 428s are running in Mustangs and Torinos before saying they are lacking at the drag strip.

Yep, ya beat me to it.  The surface area of the piston means nothing.  Sure, you have more expanding gas pushing against the piston, but if you do the [i]vector sum[/i] of the forces, it will be the same as a flat disc with the same cross-sectional area.  Since the force (per unit area = pressure) from a gas is always normal (perpendicular) to the surface it's pushing on, a lot of the force pushes [i]sideways[/i], not [i]up[/i].

The Hemi was banned in 1965 because it was not available in a factory automobile.  Same reason Nascar banned the 427 SOHC, High riser, and Tunnel Port. That left the 427 medium riser and later Boss 429 which did very well against the Hemi especially in the slaughter of 1969. The death to big blocks in Nascar was not the motors per say but the aerodynamics of the bodies. 1971 saw the restriction of 305c.i.(?) in the aerodynamic Mopars and Fords.  I read somewhere that given todays advancements, Buddy Baker said he could probably run 245-250mph in his old #6 Daytona.

Well, not always. The 2.6L 4-banger installed in some Chrysler and Mitsubishi products also had hemispherical combustion chambers in it, and it produced neither power nor speed (except for the tubo version)...

The new Hemis are not true hemis.  More like a canted wedge with the spark plug in the middle.



Bobwrench

335 HP? Actually, I do, having owned a few BB Chevys. The 428 CJ was a piece of shit compared to the 427 medium riser and other FE engines.

You show your ignorance by listing the 428CJ's horsepower at 335 which was purposefully stated low by Ford for racing purposes.

Look at NHRA weight to actual horsepower ratings which determine what class a car is placed in:

335 HP 428 1969 Mustang Mach 1  8.71 lbs/HP
335 HP 383  1970 Road runner  11.39 lbs/hp
375 HP 440  1970 Road runner 10.30 lbs/hp
425 HP 426  1970 Road Runner 8.77 lbs/hp
425 HP 426  1970 Hemi Cuda 8.56/lbs/hp
375HP 402  1970 Camaro  8.75 lbs/hp
425HP 427 1969 Camaro 7.92 lbs/hp

LeBlances SS/F CJ Mustang ran a 9.57 on a 10.65 index and you state the CJ is a POS? He has a faster ET than the national record holder in SS/E which is a big block 68 Camaro.

Piece of shit compared to a 427?  Having run both motors I will agree 427 is faster and stronger...duh
427 was also more expensive to build and was definitely not an emissions friendly motor.  427 also craved high compression ratios which the 428 did not. 427 was a pain in the ass to drive on the street, 428 ran sweet.

"Hemi" means "Call me when I blow my tranny."

You show your ignorance by trying to compare prepared race motors to stock motors. The L88 still comes out on top. I don't like your motor, it sucks, get over it. And yeah, I like my Fords, too. Have a happy Thanksgiving!!!

Man the testosterone is just dripping all over this thread!!
Reminds me of the time when REAL men walked the earth, and METRO-SEXUALS were unheard of!!
Kinda makes me want to go out and strip down an engine.[Tim 'Tool man Taylor] More power!!!!ARRRGH!![/Tim Taylor]

Regarding the 68 cj mustang that car and driver tested and went on to say was the fastest production car they had tested.(ran like a 13.5 1/4) It was later disclosed that ford had given them a "ringer" tuned by Dyno Don Nickleson, one of the top ford racers of the 60's. Remember good reviews ment sales at the showroom. Pontiac was well known for doing this with the GTO.

The cj429 was actualy a better breathing engine than the 428 since it used large staggered valves much like the BB chevy.

The SOHC 427 was a monster, but it had a major problem - the timing chain was almost 10 feet long and was prone to stretching. The SOHC had a lot more success in drag racing than NASCAR for that reason.

The surface area thing isn't quite right. The main advantage is the fact that the flame front travels directly downward. The cross flow orientation of the valves helps a lot too.

The Hemi's production was ended in 1971 not because of emmissions so much as insurance costs, Nader's safety nazis, and the fact that the Hemi heads were prohibitively expensive to produce. The valve train was also an issue, with two rocker shafts pre head and those loooonnggg exhaust rockers.
Chrysler had a replacement design slated for full production as a replacement for the wedge engines, and it had canted/splayed valves that were not shaft mounted and a combustion chamber that was not quite as close to a true hemispherical shape as the originals. The new engines were canned before they went into production because of the energy crisis and emissions legislation.