More confused???

Just traded in a 2002 Dakota 4.7L, In that truck I used Autolite 5224's, which are a direct replacement for the Champions RC12MCC4, gapped at .040. I now own a 2005 Dakota 4.7L with only 19,700 milesand again I will change to the Autolites when the time comes. After reviewing the Autolite web site this is what I determined:

Autolite 3923 used in the V-6's - one stage colder than a stock plug in a modified 4.7L V-8 , standard tip
Autolite 3922 used in the V-8's (4.7L HO) standard tip
Autolite 5224 used in the V-6's & V-8's with special power tip

http://www.power-21.com/honeywellpower21i/autolite.aspx

Like I mentioned before the 5224's gave me better mileage and a smoother idle in the 2002 Dakota.
My opinion, stay away from the Platinums...

 

This is an excellent thread that discusses the differences in the 3922, 3923, 5524, etc. It's a bit long but there's a lot of good information in it: http://www.pavementsucks.com/forums/...hp?topic=64498

Here's a summary:

Use the 3923 for more power & *slightly* better mileage, if you're willing to swap plugs every 15-20k miles.

The 3924 has not quite as much power/mileage gains, but better than platinums...also change ~15-20k miles

Use platinum variety plugs, and change intervals are once or twice as long as you own the vehicle, at the cost of power and mileage (due to higher electrical resistance)


From Autolite:
Autolite Copper Core Spark Plugs:
• Are guaranteed for two years to deliver quick starts, improved fuel economy and smooth acceleration, no matter how many miles they go
• Feature our exclusive copper-glass seal that bonds the insulator, terminal post and center electrode together assuring full required voltage at the spark gap for dependable performance
• Offer the best suppressor resistor in the industry for superior suppression of radio frequency interference.
• Multi-rib insulator reduces danger of "flash-over" outside of insulator.
• Cold-formed steel shell precision rolled threads conform to SAE/ISO standards.
• Copper-glass seal bonds insulator, terminal post and center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leakproof).
• Longer insulator nose provides longer fouling path to control fouling deposits.
• One-piece terminal post firmly sealed within ceramic insulator; provides positive contact between spark plug wire connector and plug.
• Resistor reduces radio frequency interference (RFI) and electrode erosion.
• Copper core center electrode sheathed in high chromium-nickel alloy; provides superior heat dissipation and durability.
• Chromium-nickel alloy ground electrode resists gap growth and maintains precise spark gap longer.


Ok, now some info on spark plug heat ranges:
***By changing the heat range to a colder plug may change the combustion chamber by 70-120 degrees, according to Autolite.

***"Spark Plug: Heat Range Facts:
Typically, engines which are stock or are only slightly modified, can use the original equipment (OE) recommended spark plug.

Racing Modified Engines- Generally, any engine modification that alters the overall compression ratio of the engine will involve spark plug selection issues. One thing to consider is heat range. The heat range of the spark plug determines how much heat the spark plug is capable of REMOVING from the combustion chamber. The heat range of the spark plug does not increase or decrease horsepower. It changes the temperature of the tip of the spark plug. If the heat range is too cold, the deposits will not burn off the tip and the spark plug will foul. If the spark plug heat range is too hot, pre-ignition can occur (ping).

A switch in heat range of the spark plug will change the temperature of the spark plug tip by 70-120 degrees. If you are unsure of the correct heat range to use, always start with a colder spark plug. If the plug is too cold, the plug will eventually foul and a misfire will occur. This will not hurt the engine. Unfortunately, though, if a spark plug that is too hot is inadvertently chosen, preignition and detonation can severely damage your engine. Don't go to a hotter heat range unless you've consulted your engine experts.

Some various info on the 522X Series versus the 392X Series:
-The 522X plugs are truck-type plugs and are the recommended plugs for the 318.

Autolite plug numbers ending in a 4 indicate that the plugs are the normal heat range. As this last digit decreases, the heat range becomes correspondingly one range colder.

The difference between the 5224 and 3923 plug is #1, Heat Range (3923 is one step colder) and #2, the tip on the 5224 is a "Special Power Tip". (Just an extended tip...i've read and looked for any types of problems when running the 3923's and haven't found anything yet. The difference between the 3924 and 3923 is the heat range...nothing else. The 3924 is the stock heat range and the 3923 is one step colder. The 3924 plug has the normal heat range for our trucks. The 3923 plug is one range colder. Generally, if you frequently run a heavy load and/or run often at WOT, the colder plug gives greater benefits.

It seems the 3923's are geared more towards the 318/360. The 3923's would work, but I think the main difference is how
long the nose is. I have NOT found any incidents were trucks were experiencing any ping/knock, so the shorter nose of the 3923 (along with more fouling etc) wasnt necessarily needed. I dunno much about the "quality" factor, or the main reason the Autolites seem to be preferred. I did hear back from some people running the 5224's and heard they got better idling/slight mileage increase.

Remember it is not the plug that makes an engine run lean...it's the heat range that can cause preignition (pinging) and can cause excessive heat inside the combustion chamber....therefore appearing to be lean. (Not good for performance at all and mileage can suffer even worse than with a colder plug.)

Some replies from Autolite:

"According to our data the 5224 is the recommended Autolite spark plug for the 1997 Dodge Dakota pick-up truck 5.2L (318 CID) engine. Autolite does not offer a colder version of the 5224. The next step colder plug in this plug type family is the 3923.

We are aware that there are a large number of Chrysler enthusiasts using the 3923 instead of the 5224. Under routine driving conditions associated with normal stop-go traffic and typical highway driving, the 5224 is the plug we recommend. However, if you are driving your Dodge under heavy acceleration, excessive highway speeds, high idle or high rpm conditions, then you may want to consider using the 3923."

So Autolite is directly stating the 3923 can and should be used for vehicles under "heavy acceleration, excessive highway speeds, high idle or high rpm conditions"

It is important to understand that spark plugs CANNOT create heat, only remove it! The spark plug works as a heat exchanger, pulling unwanted thermal energy away from the combustion chamber and transferring the heat to the engine's cooling system. The heat range is defined as a plug's ability to dissipate heat. The rate of heat is determined by:
-The insulator nose length
-Gas volume around the insulator nose
-Materials and/or construction of the center electrode and porcelain insulator

Spark Plug Heat Range:
-A spark plug's heat range has no relationship on the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors:
-The length of the ceramic center insulator nose
-The insulator nose's ability to absorb and transfer -combustion heat
-The material composition of the insulator
-The material composition of the center electrode
-The longer the insulator nose, gives a larger surface area exposed to combustion gasses and heat is dissipated slowly. This also means the firing
end heats up more quickly. We are talking about exposed ceramic length, not extended tip length.

Good stuff:
Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. No matter what the plugs are installed in, be it a lawnmower, a boat, your daily driver or your race car, the spark plug tip temperature must remain between 450°C to 850°C. If the tip temperature is lower than 450°C, the insulator area surrounding the center electrode will not be hot enough to deter fouling and carbon deposit
build-ups, thus causing misfires.

If the tip temperature exceeds 850°C, the spark plug will overheat which can cause the ceramic around the center electrode to blister as well as the electrodes will begin to melt. This may lead to pre-ignition/detonation and expensive engine damage.
In identical spark plugs, the differences from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing temperature is increased by 10°C to 20°C.

So if the plug's tip heat up, you will get pinging. So drop down one heat range and lower the plug's tip temps by 100 degrees Cent! AND projected tip plugs increase the temp by 10C-20C, I am beginning to think
that I will be going to a cold range plug!

A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity. This is probably why the stock heat range plug is used, because of emissions and the ability to burn off oil and carbon???????

Conversely, a "Cold" spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range can be necessary when an engine is modified for performance, subjected to heavy loads, or it is run at high RPMs for significant periods of time.

What exactly does a colder plug do differently than a hotter plug? They conduct heat better... not unlike a more efficient heat sink!

Why don't auto manufacturers install colder plugs from the factory?? They also have to deal with the EPA, a hotter plug will stay cleaner better (i.e. less chance of fouling)... it is my belief that hot plugs are installed from the factory b/c 90% of the population won't change the plugs for 50-60k miles.

A common misconception is that spark plugs create heat. They don't. A heat range refers to how much heat a spark plug is capable of removing from the combustion chamber. Selecting a spark plug with the proper heat range will insure that the tip will maintain a temperature high enough to prevent fouling yet be cool enough to prevent pre-ignition. While there are many things that can cause pre-ignition, selecting a spark plug in the proper heat range will ensure that the spark plug itself is not a hot spot source.


The 522? series is similar to the 392?, but has an extended tip that puts the spark farther down in the chamber, which has an effect
similar to slightly advancing the ignition timing.


Think platinum plug are better? See what Autolite directly stated:
"The use of platinum has no effect on performance or heat range value. The sole intended purpose of platinum is to extend the service life of the spark plug. Gap erosion is a natural condition that occurs every time the spark plug fires. After a considerable period of time, the gap growth is to a point where the plugs are loner serviceable and must be replaced. Platinum is a metal element that resists the effects of spark gap erosion. By using tiny platinum pads on both the center wire electrode and the ground wire electrode, spark plug manufacturers are now able to provide a plug with an extended service life. No matter what brand of platinum spark plug you choose, the use of platinum should not affect the performance of the engine."

Also quote from Autolite:
"If you will be driving your Dodge under hard acceleration, with excessive speed, hauling heavy payloads or pulling trailers, then the 3923
may meet your performance expectations. However, if you drive your Dodge in a more conservative manner such as stop-go traffic associated with routine driving conditions, then the 3924 would be preferred."

The center part of the 5224 plug is supposedly designed for the best burn for low rpm torque and the extra length of the tip is supposedly designed to get the spark closer to the fuel injector spray.

It may well be that the design of the 392x family gets a better burn at high rpms. I know that the Autolites were used on a lot of the mopar muscle cars in the 70's.

 

Great reading! I feel much more informed on this subject. Thanks!What my question still is why did the factory Champions come gaped at between 0.36 to 0.37 and not even close to 0.40 as specified? I only had 16k on the plugs when I changed them. In the service manual and on the hood spec sticker it list the 4.7 at 0.40 spark gap but nothing on the HO series in regards to a different spark gap. The HO has a slightly more aggressive cam shaft and some other slight differences than a regular 4.7. What I'm getting at is there a hidden spec for HO spark gap that is under 0.40?

 

Thanks ChadJK...

Very good reading and I checked out the link also...

Very interesting !!!!!!!

 

So Autolite is directly stating the 3923 can and should be used for vehicles under "heavy acceleration, excessive highway speeds, high idle or high rpm conditions".

Heh. That's me!

 

as for the champions, everyones truck is messed up from the factory. when i changed out my plugs to the 3923 and checked each champion gap, some were at .035 some were at 0.55 and some were .040. i think they just threw the plugs in to get the truck into production and had to deal with the mess later

 

Mine were NGK stock and still messed up.

 

Ok I'm a bit freaked here. Since this subject brought out a bunch of info, I decided to check my old plugs again. The number on the factory champions are RC7PYCB4. The hood spec sticker says they should be rc12mcc. What the hell? I posted some pics here. Anyone know what happening here?

[IMG]local://upfiles/40810/DA3F5062FB534AFC837A3B4FF6C5B9AE.jpg[/IMG]

[IMG]local://upfiles/40810/A5ABD23913D243249A4946C3280CF4DB.jpg[/IMG]

[IMG]local://upfiles/40810/C26F3F0B97494E07A6AF4AAE8ECADD9C.jpg[/IMG]

 

I just did plugs in mine and the old ones were all at .047???

 

resistor plug, Platinum center electrode, resistor plug, 14mm, 3/4" reach, 5/8" hex head, projected tip, dual ground electrode. 2 plugs per pack ',325);" onmouseout=hidePreview(); bgColor=#c6e6ff>
Champion
Single Platinum
3340-2
RC7PYCB4
$5.15



Summary of HO engine feature differences

(Compared to standard 4.7 liter engine)







1. Block - Detonation sensor bosses in the valley
10. Intake - low-restriction intake system (different resonator, air filter, air filter hose and housing)

2. Camshaft - custom profile lobes (designed for increased performance)
11. Knock sensors - two, stereo

3. Connecting rods - modified, with floating wrist pins (vs pressed-fit pins in standard V8)
12. Main bearings - tri-metal (vs bi-metal in standard V8, designed specifically for the HO engine)

4. Crankshaft - forged steel (vs cast iron in standard V8)
13. PCM calibration - unique programming

5. Crankshaft damper - unique to H.O.
14. Pistons - dome shaped for increased compression ratio

6. Cylinder heads - different shaped combustion chambers (for improved airflow). The letters "H.O." are cast on the front end of the heads.
15. Spark plugs - platinum tipped

7. Exhaust tip - chrome (2002 models only, decontented for 2003 models. Available only as a one-piece assembly with muffler)
16. Valves - unique exhaust valves (same lift as standard V8)

8. Fuel injectors - higher flow (+3.3 lb/hr)
17. Valve springs - upgraded valve springs (intake & exhaust. Larger diameter wire and more coils)

9. Intake manifold - modified (shorter runners)