gas in the oil

Discussion in 'Parts Interchange' started by capt.redbeard, Mar 7, 2005.

  1. capt.redbeard

    capt.redbeard Member

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    I just started taking apart a 302 for a rebuild and noticed gas in the oil, but can't find where it came from. Could this be caused by "reverse blow-by" due to a bad seal in the carb draining gas into the cylinders? Is it possible for a worn out fuel pump to leak gas into the motor? The engine is from a 73' 1/2 ton pickup that was parked for 8-10 years and not started.
     
    capt.redbeard, Mar 7, 2005
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  2. Grabber5.0

    Grabber5.0 Gear-head wannabe

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    my carb did that to me the first time i rebuilt it. i can't remember if it was the needle not seating or the accelerator pump not being tight enough, but i ended up with at least a gallon of gas in the oil by the time noticed. The pressure in the fuel system was just pushing the gas into the carb and it was draining down the intake. Fortunately it wasn't starting either, so i didn't have a chance to drive it that way
     
    Grabber5.0, Mar 7, 2005
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  3. elliot

    elliot Member

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    A bad fuel pump will do it too .
     
    elliot, Mar 7, 2005
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  4. capt.redbeard

    capt.redbeard Member

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    Thanks for the info.
     
    capt.redbeard, Mar 7, 2005
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  5. rayzorsharp

    rayzorsharp I "AM" a Maverick!

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    It is most likely one of the two above items, carb or fuel pump. I run an electric fuel pump with a Holley carb. I got trash in my carb from dirty fuel lines therefore the needle and seat was staying open. Before I realized what had happened I filled my cylinders up with gas, which of course went to the oil pan. I checked my dipstick and it was about a quart over full.
    I have had a couple of instances in the past where the diaphram on my fuel pump went bad and pumped fuel into the oil pan...most likely your problem in my opinion.
     
    rayzorsharp, Mar 7, 2005
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  6. roush16

    roush16 Member

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    i also would say fuel pump espeacially if its manual i had that happen in my 1978 f150 bigblock 400m it was showing low oil pressure i didnt think nothing because a modified doesnt show good oil pressure then the knocking started i was just a kid so i put oil treatment in it and that did nothing so my hears the thing and asked if it had oil so he start looking around a felt the oil filter and it was hot and then he looked at the dip stick and told me it was the fuel pump and by that time she was toast and he was hot so i learned a good lesson that day if i dont know ask.. travis e mccarney
     
    roush16, Mar 7, 2005
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  7. rayzorsharp

    rayzorsharp I "AM" a Maverick!

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    Did you say that all in one breath???:eek:
     
    rayzorsharp, Mar 7, 2005
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  8. 74merc

    74merc computer nerd

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    My old Holley 600 leaked down as you described.

    Washed the cylinder walls clean as a whistle every time I parked the car. :rolleyes:

    Suprisingly, it didn't seem to be any worse for the wear, and it didn't really add enough gas to make a difference, just enough to smell.

    Autolite 4100 and all is well...
     
    74merc, Mar 19, 2005
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