Ramforums

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Agreed, cleaner burn.

Hemi comes from Hemispherical heads but I believe the newer Hemi since rereleased in the 3rd gen Ram and on are not actually Hemi's just a naming thing because it sells. They do two plugs per cylinder because it helps for a cleaner burn.

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I know this thread is old, but I just tuned up my hemi tonight and came accrossed this in my alldata program i use at my shop.
DESCRIPTION

The 5.7L engine (345 CID) eight-cylinder engine is a 90°V-Type lightweight, deep skirt cast iron block, aluminum heads, single cam, overhead valve engine with hydraulic roller tappets. The heads incorporate splayed valves with a hemispherical style combustion chamber and dual spark plugs. The cylinders are numbered from front to rear; 1, 3, 5, 7 on the left bank and 2, 4, 6, 8 on the right bank. The firing order is 1-8-4-3-6-5-7-2.
This is listed under engine description.

Now I ended up using autolite platnums. I dont plan on going longer on interval i did it because I dont normally use champions, but when I crossed the champion plug number on my napa direct sight it said that the autolites where the oe equivalent, and under the champions it said they wherent an exact oe designed match...so I went with the autolites. I use them more commonly any way so I didnt give it a thought until I got home and started reading some things...they where only like 50 cents more my cost so I dont mind about that, and it runs great. So Im gunna leave them in for now see what happens...

Spark Plug - Copper Plus - OE Type
Product Line: Champion Spark Plugs
Comments: @Gap .045"@;2 Plugs Per Cylinder Required of Same Heat Range;Double Platinum Or Iridium Is Recommended For Waste Spark Ignition
Per Car Qty.: 16

Spark Plug - Platinum - OE Type
Product Line: Autolite Spark Plugs
Comments: @Gap .045"@;2 Plugs Per Cylinder Required
Per Car Qty.: 16


Heres the napa site listing you can see the top too are listed oe. When I crossed the numbers only the autolights said oe. weird

Spark Plug - Platinum
Product Line: Autolite Spark Plugs
Interchange Mfg.: Champion Spark Plugs
Interchange Mfg. Part Number: RE14MCC4
Select To Compare

Spark Plug - Copper Plus
Product Line: Champion Spark Plugs
Interchange Comment: Not a direct cross. Check cataloging for specific application
Interchange Mfg.: Champion Spark Plugs
Interchange Mfg. Part Number: RE14MCC4
Select To Compare

get the plugs fron the dealer. If you have the "MDS" the cylinder cut out, you have to use regular plugs!!! there about 70 bucks for the 16. be careful cuz the 2 by the brake booster are tough. i did mine about 8k miles ago. You should change them every 30000 miles.

dont use platinum plugs if you have the cylinder cut out. Yeah the hemi motors are not true hemi's!!! that kinda sucks!! wonder when they are going to make the 426 hemi again?????

Did you not read any of my posts?

I dont get the whole if you have cyl shut down dont use platnums... chevys have used platnums with cyl shut down for years...

If it's a Hemi of the modern years it has 16 plugs. They all do after the year 1905.

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A brief description of Hemi (from "hemisphere") or "crossflow cylinder head" is a design of internal-combustion engines in which the cylinder head's combustion chamber is of hemispherical form. The term, "Hemi engine" is a trademark of Chrysler Corporation, though the concept is used by many manufacturers.
A Chrysler Hemi engine is one of three different internal combustion engine families from Chrysler that are Hemi engines; in other words, they utilize a hemispherical combustion chamber. A hemispherical (inverted bowl-shape) combustion chamber allows the valves of a two valve-per-cylinder engine to be angled rather than side-by-side. This design also allows the placement of the spark plug nearer to the center, which is mandatory, given that there is minimal quench and swirl to burn fuel gasses thoroughly and quickly. A hemispherical combustion chamber often requires a dome-shaped piston crown to maintain the desired compression ratio.
Hemispherical cylinder heads have been used in some engines since they were first used by the Belgian car maker Pipe in 1905. Most applications have been in higher-priced luxury or sporting vehicles, because the hemi design is more expensive to build. Among first applications with hemispherical heads were also Peugeot Grand prix Car 1912 and Alfa Romeo GP car in 1914.

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White Truck Club Member #29
Military Club Member #41
Gun Club Member #35
Motorcycle Club Member #17
Hemi Truck Club Member #77
Crew Cab Club Member #2
Tattoo Club Member #21
Redkneck Club Member #13