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11:32:09 - 05/28/2024
V6 Dakotas
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trev1
Dodge Dakota
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10/18/2008
19:51:49
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 Subject: Re-Ring or Rebuild it
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Ok.... 92 Dodge 3.9 v6 4wd 265,000 miles.
We reciently bought a new truck (Dodge Ram 1500 4.7 v8) so driving the Dakota has become un-necessary. It has been getting lower and lower fuel mileage, engine power is dropping also. The engine runs smooth and holds good oil pressure but is burning about a quart every 600 miles or so. Mostly under hard acceleration. (HA)
I have checked the vaccuum pressure at idle, it is a steady 15 in.Hg at idle and raises to about 22 in.Hg when the idle is raised to 2000 RPM. Although it drops instantly to 5 in.Hg and instantly goes to 22 in.Hg when the RPM's are increased very fast above 2000. The vaccum does not vary at any point other than when the engine RPM's are changed.
Comression in the cylinders varies..
#1. 120 psi without oil and 125 with
#2. 90 psi without oil and 100 with
#3. 110 psi without oil and 125 with
#4. 125 psi without oil and 130 with
#5. 122 psi without oil and 125 with
#6. 125 without oil and 130 with
The engine does have the timing chain noise and but does not knock in the bottom end.
My question is:
Do I Re-Ring the Pistons and call it good..OR...
Do I Re-Build it and call it good...
Whats everyone's opinion....
I have the tools and shop available to do it and time is not a problem (I'm not driving it very much).
Give me your honest opinion and suggestions on which parts you would use.
Thanks..
Trevor in SWMO..
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harry from ct
Dodge Dakota
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10/18/2008
23:58:08
| RE: Re-Ring or Rebuild it
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buy a rebuilt crate motor from summit racing
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dakota49
Gen I
10/20/2008
22:09:47
| RE: Re-Ring or Rebuild it
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Hello Trev1, if you want to rebuild it, then go for it, since you have your new truck, you can tear it down and take your time, and spend as you can afford it. As for just putting new rings in it, that depends on a lot of things. Like how worn are the cylinders? If they are more than .020 worn new rings won't hold for long, but having the block bored isn't cheap either. If you just want to get it to run so you can get rid of it, or to have as a back up then going the cheap way isn't so bad. One thing though, the valves can help cause the low compression also.
Worn valve guides, can cause low compression. With the kind of miles you have on that truck I would suggest taking it apart, and find a machine shop to check the bores, crank, and valves then decide what you want to do. Trust me it can get very expensive very fast.
Good Luck
Dakota49
1988 3.9 4X4 5speed
dakota49
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trev1
Dodge Dakota
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10/21/2008
17:01:07
| RE: Re-Ring or Rebuild it
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Yep, I've thought of that... Im afraid that when I tear it down the dollars will fly. A Re-Ring kit from autozone with new pistons ans cam,lifters etc... is $350. I guess it could be ALOT worse than that.
Still havn't made up my mind. It is still in the front yard with the "For Sale" sign on it $1500.00. We will see what happens.
Trevor in SWMO
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dakota49
Gen I
10/22/2008
20:58:06
| RE: Re-Ring or Rebuild it
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Trev1, if you decide to rebuild it, let me know and I'll try to help you, I'm in Rogers, Ar. so we aren't far apart.
Good Luck with whatever you decide to do.
Dakota49
dakota49
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J and J Auto
GenII
10/22/2008
23:32:27
| RE: Re-Ring or Rebuild it
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Message:
that 90 to 100 would idicate you also have a valve
leaking a little
If you look at the auto parts stores they have
rebuild kits avalible but you would need to
check the crank first its only around $100 to have
it bored its all upto to you witch way you want
to go a good low mileage used motor is around $600
a reman is around $1,200 and up
The last time I did a comp test I was amazed
every cyl was right at 125 that is unusual to
have them all identical must be from the synthetic
oil keeping everything good with little ware
I went to use my dak today and my starter is gone
just clicks 126,000 miles bummer besides light
bulbs that will be the first part I had to replace
in 14 years LOL excluding things like plugs and
wires that is reg maintainance not to bad at all
Larry
J&J Auto
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stevedak
Dodge Dakota
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10/28/2008
06:11:01
| RE: Re-Ring or Rebuild it
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Everybody has different criteria when it comes to how much money to dump into a use vehicle, here's mine.
Don't do anything (no rebuild or reman) unless you plan to keep it and use it a few years more. Spend the money for your benefit, not for resale.
If you take the engine out and tear it appart, you should not put it back without new main bearings, rod bearings, and rings. Some more experienced guys may be able to look at journals and bearings and say whether they are good enough but I wouldn't risk it, the parts are too cheap. A crank set (crankshaft and bearings) may only cost $65-$90 more than the bearings alone. If you want a real improvement, count on doing head work. If they are not damaged, they clean up pretty easily. Email me if you want more details. THe costs really go up if you have to bore it. Don't forget the oil pump!!! You'd be pretty pissed to do all that work and then have your old pump go out and ruin it all.
I did a rebuild for $800 which included some other miscellaneous stuff. cleaned up the heads myself, new crank kit, oil pump, cam bearing, timing set, two new pistons, new gaskets and seals. Honed cylinders, no re-bore.
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