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Ideas on refreshing a 170K mi V8?

Discussion in '40- & 55-Series Tech' started by baldboy, Aug 15, 2006.

  1. baldboy

    baldboy

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    I have a 95 Yukon I use to pull my FJ40 and even without the 40 hooked up the Yukon is sluggish as hell up hills etc...


    The motor uses little oil and has been very reliable so I am shying away from rebuilding it yet. (Mainly cause I have little experience with rebuilding motors)

    I changed the air filter, fuel filter, plugs, wires, etc....

    I need an inexpensive way to give the truck new life again.... KEY WORD-Inexpensive-

    I have heard that getting a head reworked helps-what does this involve and would it help my tired motor?

    Any other ideas?
     
  2. fj40charles

    fj40charles

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    If it is sluggish going up hills (unloaded without a trailer, I'd say the motor may need to be refreshed.

    Make sure the low power is not due to something else... Any chance you have a clogged catalytic converter?
     
  3. Degnol

    Degnol

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    I had a '95 Yuckon(25K miles) and it was a dog. I'd say on the cheap that a Flowmaster-type muffler and maybe a chip. My '98 Yuck has a Vortec and is otherwise identical and runs very well all through the rpm range.
    Start with the basics and do a compression test, if it is WNL, the knock-off Flowmaster (about $80 installed) and a chip (about $230-50)
    GL

    Ed
     
  4. baldboy

    baldboy

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    .. Any chance you have a clogged catalytic converter?[/quote]



    How did you know?

    Seriously (the cat has been going out for a few weeks now).
     
  5. fj40charles

    fj40charles

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    How did you know?

    Seriously (the cat has been going out for a few weeks now).[/QUOTE]

    My friend owns a 4x4 shop and I usually call to ask what he is working on. He'll probably say I call too much and bother him, but that is another issue... ;)

    One day he mentioned that a customer had problems with low power and he thought it was the cat.

    Also, I would not expect a 170K SBC engine to be all worn out if it was taken care of......
     
  6. baldboy

    baldboy

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    What about getting the heads reworked?

    Someone told me that makes the difference of night and day?>

    Thanks...
     
  7. poseidon

    poseidon

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    If it is an automatic the transmission may be the slowdown. Have you ever had your transmission serviced?

    The sluggish is also directly related to fact that it is a Chevy. ;)


    E
     
  8. baldboy

    baldboy

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    Transmission

    I had the transmission flushed and serviced about 40K miles ago.

    The fluid in it looks as clean as the day it was changed.


    I know its not a racecar but it had some punch to it 100K miles ago.

    How much would an entire rebuild for that motor cost? (If I did it myself)
     
  9. CruisinGA

    CruisinGA

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    1) Fix that cat
    2) replace fuel filter
    3) have injectors cleaned and serviced
     
  10. kulangot

    kulangot

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    If your cats are bad, you'll have serious performance issues. Pretty easy to pull them off and replace or even gut them. BUT, you should figure out if you a fuel injection problem first otherwise if your running waay rich and fowling plugs you'll just kill the new cats as well.

    Look at the plugs. Do a vacuum check. Check the compression. Cover all of your basics before you rebuild the motor only to find out that you have a bad EFI part that is causing it piss fuel. What is the MPG like? Any codes? Does it smell bad when you run it? I hate fool infection myself but I understand it, know how to fix it and realize that it's better for most folks daily driven and better for wheeling on the rocks. I prefer old school stuff for tinkering and fool infection for getting to grocery store and back (before I get hate mail I know it's great for rocks, I already said that).

    Moral of the story, before you tear it down and freshen it up, do your best to find out what the problem is first. If your heads are worn out, you'll see that in both a compression and vacuum test. Ideally, you'd get a leak down test done, that will pinpoint what the problem is if it's a problem with the motor.

    You might just have a bad sensor that is throwing off your air fuel mixture or even just a set of clogged injectors. Heck, it could even be a clogged up fuel filter. Even though I love to tinker, If it was mine, I'd drive it down to the dealer and have it checked on the code reader and 4 gas machine. That will tell you a lot for $75 bucks, money well spend, then fix it yourself.
     
    Last edited: Apr 1, 2008
  11. joesfj40

    joesfj40 SILVER Star

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    If the cat has been going out on you that often it tends to be a bad o2 sensor or a temp sensor i forget exactly what the temp sensor is called but its like a choke on a carb it will either make the car run to lean or to rich which is why the honeycombs inside the cat tend to go bad.

    Id do a intake and exhaust but only if you were to make sure that its running correctly in the first place. Maybe no cat at all I don't know the restricitions and all with your state and smog.... just my little say in this
     
  12. fj40charles

    fj40charles

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    Are you talking about CTS (coolant temp sensor)? This would affect the fuel/air mixture based on engine temps.....
     
  13. dgangle

    dgangle total rice SILVER Star

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  14. zebrabeefj40

    zebrabeefj40

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    Getting heads redone for performance does not equal cheap! Otherwise a stock rebuild on Chevy heads used to run about $250-300/pair at the shop I used to work for. That got new guides, New iron heads from Summit/Jegs aren't a whole lot more and will net more power gains if you're set on that route.

    IIRC a new Goodwrench motor for that year is about $2100. A stock rebuild at the shop I used to work for wasn't a whole lot less than that after all the block work, new pistons, rod rework and assembly. Having the shop do the assembly got a warrentee (as does the new GM motor). Doing the work yourself does not get you a warrentee for the most part. Warrentee counts for a lot IMHO on a DD. :)

    I would look at swapping out the O2 sensor though. I have found that definitely helps improve performance with those motors. Was maybe $35 from Autozone for a Bosch.

    HTH,
    Nick
     
  15. llih

    llih

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    How does the exhaust smell? Converters when they are going out can sometimes cause the exhaust to smell real bad. If your not sure the cat is bad, take it to a smog shop that you trust. Where I am at they will test the entire system for $25.00. That way you will have a pretty good idea of what is wrong before you start replacing stuff. It could be something simple and not cost a bunch of money.
     
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