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black oily spark plugs...???

Discussion in 'The Garage' started by cheyennesuper, Jan 22, 2005.

  1. cheyennesuper

    cheyennesuper Registered Member

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    Let me start from the beggining...My '73 blazer is getting spark and gas but it will not run.It doesn't even pop when turning over and its turnin over real good.I know its getting gas because i looked and saw plenty of gas shooting in the venturies of carb while my dad pumped the accelerater.I removed the plugs to see if they are wet and nope.I dip the number one plug in gas and it popped once on the number one cyl. when i turned it over.I thought maybe its compression so i took the rest of the plugs out to squirt a little oil in the cylinders and the plugs nearest to the firewall are all covered in what looks like used oil.Can anyone give me some advise?Thankyou...
     
  2. g_mo

    g_mo 1/2 ton status

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    sounds like the plugs are fouled. if the truck has been sitting for a while, oil may have drained past the valve seals and fouled the plugs. put some new plugs in it or clean the ones you got real good and see what you get.
     
  3. R72K5

    R72K5 Banned

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    sounds like it needs stem seals and/or rings too

    try new plugs and see if they oil foul again, if so then time for work

    good luck
     
  4. clstolten

    clstolten 1/2 ton status

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    I had a 350 in my 69 camaro that had bad rings would foul the plugs to the point it would run bad every 100 miles. A trick to clean the plugs and combustion chamber if you get it running, is to run a large cup of water through the engine while it is just above idle. Pour the water in slow enough that it doesn't stall the engine. Makes for a nice and clean engine if you have to tear it down for inspection. Steam cleaned. I used do the water trick every other day until I had the money to get the engine rebuilt. Your fouled plugs made me think about it. The fact that it is only the plugs toward the firewall make me think it is your valve guides. You might be able to do a cheap fix by installing umbrella type seals on them.

    Also, if you are worried about putting water in your engine, I understand that tranny fluid works just as well. I wouldn't use tranny fluid if you have catalytic converters.
     
  5. beater_k20

    beater_k20 Banned

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    screw all that other crap! do a compression test and/or a leakdown test. that will tell you exactly what's up, the rest of the stuff mentioned is just a bandaid fix for a bad situation.
     
  6. clstolten

    clstolten 1/2 ton status

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    Sometimes a bandaid fix is just what you need until you have the time or money to fix it properly. The water trick will remove carbon buildup from the valves and improve the valve seal. But yes, definently do a compression, and leakdown test.
     
  7. diesel4me

    diesel4me 1 ton status Premium Member

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    clean the oil returns

    The oil return holes in the head might be plugged up with sludge,and not allow the oil to drain back down into the block,this will aggravate any valve seal problems,since the valve stems wil be swmming in a puddle of oil,even good seals will suck oil past them if they are submerged in a puddle of oil--the fact that mostly the rear plugs are fouling tends to point to clogged drain holes in the heads,cause the motor is lower in the back than the front,and the return holes nearest the firewall are usually the ones that clog first..pull the vale covers and have a peek--if its nice and clean,with no sludge--better start saving for a rebuild--non foulers on the affected plugs will get you by for awhile...:crazy:
     
  8. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

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    I you are running an automatic trans and the only the back to plugs are fouled on the passenger side, it can be something other than valve seals. I had a ruptured vaccum modulator on a TH350 in my nova and it fouled the back to plugs on the passenger side in a very short time. Saw it smoking at night when looking back throught the rear view mirror. Thought I broke some rings it smoked so bad. further inspection revealed that while the plugs were oil fouled, they were white in color (big tipoff for burning ATF). Just so happens that the vaccum line for the Trans was in the port that fed the back to cylinders on that side. The leaky modulator allowed the engine to suck the ATF out like a fat kid sucking down a chocolate shake through a straw. (in other words FAST!).

    Sounds like they were oil fouled to me. Valve stems worn/seals brittle or poor ring seal. Do the compression test and leakdown test like it was said for a better diagnosis of the problem.
     
  9. gmchevy

    gmchevy Registered Member

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    i had the same problem with a 79 that i owned, turned out that the last two lobes on the cam were flat. major carbon build up
     

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