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ADAM
Dodge Dakota
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3/22/2008
19:11:46
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 Subject: info?
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Message:
I have a 93 4x4 with the 3.9 I was wondering what I could do to get better gas milage out of this truck? I have a V8 tb, advanced the crank sen. 1.7 roler rocker, and it did get a new used tranny. (burnt the clutch on the old one up right before the 200,000 mark) I plan on putting a set of 3923 spark plugs and a 180f thermostat in. also what would help the truck in the high rpm range? it does not seem to get up and go like it used to. thanks for all the help its much appreceated
Adam
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Kowalski
GenIII
3/23/2008
07:59:24
|  RE: info?
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At 200,000 - maybe a rebuild ? Have you checked the compression, to see if wear is responsible for the lessened performance ?
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Adam
Dodge Dakota
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3/23/2008
14:32:25
| RE: info?
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Ya I checked compression last summer and the highest was around 125 and the lowest was at 100 psi its a good running engine starts on a dime just I dont think it has the power it once did. Im not really wanting to spent the money to rebuild it not a v6, if it was the 5.9 maby but I cant see sticking it into a v6.
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Kowalski
GenIII
3/23/2008
14:54:32
| RE: info?
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Those numbers explain why it doesn't have as much get up and go as it used to. A 25% difference in compression numbers indicates wear - you can't expect it to get back to where it was without addressing the lost compression.
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dakownr
Dodge Dakota
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3/24/2008
09:12:41
| RE: info?
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Kowalski, would you know off the top of your head what would the maximum compression variance between cylinders be before performance is affected? Also, what is the stock compression supposed to be?
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Kowalski
GenIII
3/24/2008
17:13:17
| RE: info?
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Performance can be affected by even small amounts; that's why many performance engine builders cc their heads to get compression as close as possible. The more balanced a motor is, the better it will run. You can check more to see where the wear is - if two adjacent cylinders are identical and low it would mean the head gasket. If you redo the compression check as a wet check, squirting about 30 cc of oil into each cylinder, and readings improve - it's bore, ring,or piston damage. If it doesn't improve, it's the valves - much easier to deal with. Don't have any numbers on what your reading should be.
Lead, follow, or get out of the way
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shadetree
Dodge Dakota
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3/25/2008
07:26:01
| RE: info?
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The service manual I have says minimum compression should not be lower than 100psi and there should not be more than 40psi difference between any to cylinders.
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dakownr
Dodge Dakota
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3/26/2008
08:38:15
| RE: info?
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Ok, thank you.
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