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23:15:32 - 12/19/2024
V6 Dakotas
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dakota49
Dodge Dakota
JOIN HERE
11/10/2007
17:13:40
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 Subject: rebuilding eng.
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Trev1, I was thinking the other day if you want a little more horse power from your 3.9, when you rebuild it this winter try to get "Gapless Piston Rings" I remember reading a few years ago where Car Craft mag. did a test, they rebuilt a 350 Chevy and with no other changes used Gapless Rings and gained 10HP an 12 Lbs. Torque. But that wasn't all, they completely did away with blow by. It may even give you a little more gas mileage. I wanted to do that with mine, but let my machinest talk me out of it.
Good Luck
Dakota49
1988 3.9 4X4 5speed
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Trev1
Dodge Dakota
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11/11/2007
07:26:21
| RE: rebuilding eng.
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Ok....
This is what I hoped for. So far all I have had time to do is check out the prices of reduild kits from Autozone. They are limited and I gedt the feeling that they want to limit what goes into the engine.
Suggestions like yours starts to poen doors as to what I can use alternatly from thier kits..
Since the 3.9 is just a cut off 318 can some of the parts from it be used?. Such as rods, pistons,rings etc...
The 318 makes more HP, aren't the internal parts beefier? Better quality should coorelate into better HP.
If these parts fit shouldn't they bee easier to get and cost less?
What crosses over?
If the parts do cross over is thier any machining thet needs done to make them fit into the 3.9 block?
Anyone out there got a parts list of what they used?
I'd like to keep the motors driveability good but mild upgrades are ok, its a daily driver and gas mileage is an issue at $3.00 a gallon.
Great info dakota49..
Thanks
Lets hear from ALL of you out there thats got an suggestion, or advice.
Trevor in SWMO
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dakota49
Dodge Dakota
JOIN HERE
11/11/2007
14:07:04
| RE: rebuilding eng.
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Message:
Trev1, most all of the parts from the 318 will fit the 3.9, in fact when I had the machine shop order my parts, it was cheaper to get a set of 318 pistons, I had my block bored .030 so I had a little, well actually a lot of machine work done. I had the block bored, and honed, decked, the heads milled (same thing) crank reground, ect. I also ordered a set of ARP rod bolts, they don't have a set for the 3.9, but a set for the 340 will work fine. Oh yeah, if you have a shop do the machine work, they can custom order any kind of engine kit you would want. I replaced my cam, lifters, ect. I got stock because I didn't want to deal with computer problems. I just didn't realize at the time it could handle a little more than stock and still work ok.
Another thing, on the 318 pistons, the 2 left over and the extra rod bolts I sold back to the machine shop.Just remember though, on my engine it was completely wore out so it needed a lot of work. Another ting, you really can't say just what will need to be done to the block/heads/crank until you get it tore down and inspected to see what you will need as far as machine work. One more thing, when you talk to a machine shop see if they will give you some refercences and then call to see if they had any complaints about the work, or service the shop provided. If you have any more questions please let me know. The gapless rings, I belive will make a small increase in power, but in the long run will pay for themselves in gas savings, and a little less blow-by related problems. I had to have a couple of valve seats replaced, and all the valve springs, as well as all the exhaust valves. I also used a grind stone and drill to smooth out the intakes, and polished the exh. ports on the heads. I smoothed out the exh. manifolds, I used an extender for getting into the long part of the manifolds. I did a lot of work, but I am glad I did. If you have any more questions please feel free to ask. One more thing, you need to get some plastagauge to check the bearing clearences on the crank.
Good Luck
Dakota49
1988 3.9 4X4 5speed
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