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stevee
Dodge Dakota
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6/27/2002
04:29:36
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 Subject: 3.9 V6 odd fire?
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Is the 2000 3.9 V6 an odd fire V6? What does that mean? I know that it effects the ignition and timming some how.
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IntenseDak39
*GenIII*
 
6/27/2002
06:45:56
|  RE: 3.9 V6 odd fire?
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Message:
i believe all V6 daks are odd fire (maybe not the premags..... i dunno). All it really means is that you will have a spastic idle and can put the biggest came in there you want but wont sound like. I think it has to do with the weird timing order too. Its 1-6-5-4-3-2 while most other V6's are 6-5-4-3-2-1. Bernd can tell you more about it because i really dont know much about the electronics on these things (cant get greasy with electronics ;-)
intensedak39
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kryp2nite
Dodge Dakota
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6/27/2002
14:18:34
| RE: 3.9 V6 odd fire?
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Message:
its ok that the whole trucks shakes when it starts up right?
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IntenseDak39
*GenIII*
6/27/2002
16:12:06
| RE: 3.9 V6 odd fire?
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Message:
hehehe..... sure..... okay ;-)
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Bill the Cat
Dodge Dakota
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6/27/2002
19:35:22
| RE: 3.9 V6 odd fire?
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Message:
wrong wrong wrong odd fire comes from the fact that the block is a 90 degree block and even fire comes from a 60 degree block The 3.9 is based on a 5.2 90 degree block. In a 60 degree block the engine can be timed to fire every 120 degrees or three times a revolution. the 90 degree block fires at 90 and 150 degrees of rotation, thus it has an odd firing sequence and a rough idle as the firing pulses are not evenly spaced. If you add 120 6 times you get 720 degrees per full engine cycle and if you add 90 three times and 150 three times and add the products together you also get 720 degrees per full engine cycle. Remember= a 4 stroke engine makes two full revolutions per 4 stroke cycle. Firing order has absolutely nothing to do with odd-firing.
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IntenseDak39
*GenIII*
6/27/2002
23:36:50
| RE: 3.9 V6 odd fire?
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Message:
like i said.... i dont know everything about it but a spastic idle
i was referring to the firing order as a factor of being odd fire. Not making it odd fire.
intensedak39
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kryp2nite
Dodge Dakota
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6/28/2002
20:18:46
| RE: 3.9 V6 odd fire?
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Message:
nice save intense :þ
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IntenseDak39
*GenIII*
6/28/2002
22:21:48
| RE: 3.9 V6 odd fire?
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Message:
thanx ;-)
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Lesley
GenIII
6/29/2002
00:38:33
| RE: 3.9 V6 odd fire?
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Message:
Check your plugs - mine almost shook itself apart,
turned out 2 of the plugs were fouled. Or perhaps
you have the wires mixed up.
97 3.9 CC Sport. Black. Auto 3.55, Quick D Intake, JBA Stainless headers, Autolite 3923s, stainless Borla Turbo XL & tip, V8 TB, FMS 19 lb fuel injectors, 17x10 Boyd Smoothies, JBA 9mm cables, Lakewood chrome traction bars. Have, but not installed: 3.92s, Infinity Sound System
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Bill the Cat
Dodge Dakota
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6/29/2002
16:55:07
| RE: 3.9 V6 odd fire?
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Message:
read my last line again as you are still wrong and it was not a "nice save" FIRING ORDER HAS NOTHING TO DO WITH ODD-FIRE. it has everything to do with fire relationship. If you keep your engine and computer properly in tune most of the characteristic rough idle can be minimized but you will never completely eliminate it. Sometimes mine runs so smooth that my kids sometimes try to restart the engine even tho it is still running. "97 cc 3.9 V-6
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IntenseDak39
*GenIII*
6/29/2002
22:54:21
| RE: 3.9 V6 odd fire?
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Message:
"FIRING ORDER HAS NOTHING TO DO WITH ODD-FIRE"
"it has everything to do with fire relationship"
jesus... your confusing yourself ;-)
calm down kitty!
supercharged-intensedak3.9
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Maxanimal
Dodge Dakota
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7/02/2002
22:12:30
| RE: 3.9 V6 odd fire?
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Message:
boy you're busy for a couple of days and you miss the fun posts
1st 6-5-4-3-2-1 and 1-6-5-4-3-2 are the same they just start at a different point in the order.
2nd buick built even fire 90 deg v6's with "split" journals at the paired rod journals.
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kryp2nite
Dodge Dakota
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7/02/2002
23:42:55
| RE: 3.9 V6 odd fire?
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Message:
bill?
does this subject keep you awake at night?
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sparky
Dodge Dakota
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7/26/2002
22:34:21
| RE: 3.9 V6 odd fire?
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Merl Howel has a writeup on what an odd-fire V6 is. It's based on the old Buick 225 that Jeep used in the 60's and Early 70's but the principals are the same:
http://home.off-road.com/~merls_garage/oddfire.html
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SloDak39
Dodge Dakota
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7/31/2002
14:01:33
| RE: 3.9 V6 odd fire?
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Message:
aren't odd fire ignitions a relic from the 70's?? I know the 70's buick 231 V-6 was an odd fire and then in 80 or 81, was changed to an even fire somehow.....i figured in a modern engine, there would be no odd fire but i guess not....
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Bill the Cat
Dodge Dakota
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8/03/2002
05:37:46
|  RE: 3.9 V6 odd fire?
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those Buick engines with the split crankshaft had the very nasty habit of breaking in half at around 80,000 to 100,000 miles. The reason Chrysler went with the 90 degree V-6 and also the 90 degree V-10, Thats right the mighty Viper engine is odd fire also, was so that all the engines could be machined on the same production line, saving tooling ans machine costs to, hopefully, reduce costs in building your engines. For those of you that aren't aware, this even goes to most valve train components,except the heads and camshafts. All the old oddfire 6's you guys mention are all based on V-8's. Oh and as a personal note to intense, yeah I could have done a slightly better job of explaining but most seem to have figured out that fire relationship has to do with the firing timing, ie, the 90-150-90-150-90-150 degrees of separation between each firing cycle. apparently you did not get it. But my 8 year old grandson has full understanding of the subject. Intense, by any chance are you a public school graduate????? Even fire can only be achieved in straight, 60 or 120 degree 6 cylinder engines.
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