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Chevy 6 banger guys...

Discussion in 'The Hokey Ass Message Board' started by jay, May 1, 2009.

  1. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    I have a problem that i hope someone has encountered before..I have a 292 that my dad hot rodded ..My dad and i got it running to take to the Rumblers show a few years back and made a few runs up and down the streets and everything was running smoothly..on the way down to the show it started to act up when it was under a load..almost like it was flooding out..we got to the show and thought maybe it was getting to hot making a vapor lock kind of situation..so we went to the show..left that night and everything was cool again for about 3 blocks and it started acting up again..we got it to the house and the next day i pulled the plugs and they were wet fouled..my dad investigated things further and found that the pressure regulator diaphram had gone bad..so he replaced it and tried driving the truck..it was doing the same thing..so he parked it in the garage

    Fast forward three years and now i have the truck..the intake manifold is a offenhauser unit that he modified so he could put two DGEV carbs on it..he also added a heat tube to the outside of the manifold..some old trick he did to keep the gas from puddling in the manifold..when i got the truck the old plugs were covered with a black carbon foul except #4 which was wet fouled..i went and got a hotter set of plugs and a couple gallons of gas and the truck fired off and ran smooth in the driveway..as soon as i got it out on the street and put it under a load it starts to act like it is going to die..almost like its running out of gas..even when you try to feather the peddle it acts like its going to die and then kinda catches its breath and takes off but then dies back down to barely wanting to run..

    So i started chasing things from the back of the tank to the carbs..the fuel filter is good.. the pressure regulator is holding at 3 pounds and it works cuz i have moved the pressure up and down..i started looking at the manifold..i checked all the bolts and they are tight..so i thought that maybe the heat tube was getting the manifold to hot and vaporizing the gas..so i unhooked it..i did notice that the front header tubes are really close to the intake manifold and when i got the truck running again today the front part of the intake is hot while the middle and back part of the manifold are quite a bit cooler..i have never played with a 6 banger before so i dont know if this would be an issue..

    After disconnecting the heat tube today i fired the truck and it ran real smooth in the yard..i blipped the throttle and it would stay running which it wouldnt before..still holding 3 pounds of fuel..i backed it out of the yard went down two blocks everything was running smooth..i got on the main road gave it some gas to get it up to speed and it went to hell..it started to act like it was running out of gas again...tried to feather the peddle and it wouldnt do anything...just chugged like it was running on three cylinders..finally got it to chug home..got it into the yard and put it in park and it smoothes out again..so i am at a loss..anybody run into something like this??

    The 292 is bored out 60 over..it has been balanced..polished..the head has been ported and polished..it is running a howards cam with a 430 lift..but dont quote me on it..an hei ignition..so i know its throwing enough spark..and a 700r4 trans...what would make it run smooth in park and then go south once you put it under a load?
     
  2. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,198

    fordcragar
    Member
    from Yakima WA.

    What kind of fuel pump do you have? Do you have a rubber hose between the pump and tank that might be collapsing? Is it possible the maybe there is an obstruction in the tank?
     
  3. hoggyrubber
    Joined: Aug 30, 2008
    Posts: 572

    hoggyrubber
    Member

    are the carbs set ok? how much advance do you have the timing set for with the hot cam?
     
  4. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    I had to replace the rubber hose line..it was all dry rotted and leaking..went out and watched it running in the yard and it doesnt look to be collapsing..i dont know what kind of electric fuel pump is on it..i know its not a holley brand..but it seems to be keeping the pressure up..i had a friend watch the pressure guage when i put it in drive and tried to put a load on it..it holds a 3 lbs..but when it is just sitting in the yard it wont act up..i will have to check to see where the advance is set at..it doesnt feel like a timing issue..i could be wrong..it doesnt act like its retarded or to advanced..as far as i know there is nothing in the tank..my dad had to have it made and it went in as soon as he got it..its a challenge to take out..you have to pull the bed...i did find the cam card its a 216 duration with a 493 lift
     

  5. hoggyrubber
    Joined: Aug 30, 2008
    Posts: 572

    hoggyrubber
    Member

    any progress on getting it running right?
     
  6. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    Not Yet..i went back and emptied the tank again to make sure there wasnt any nasties floating around giving me a headache..i went and put another fuel filter in just to make sure the other one hadnt gotten plugged with any debris i hadnt seen..i started it up and it was running great went about half a mile and it all shut down on me again..acted like it was running on 3 cylinders...it seems to do alright when its cold but once it hits temperature it falls on its face..i am still wondering if the headers are getting the intake hot enough to vaporize the fuel before it gets into the head..i know i have enough pressure all the way to the carbs..and i know its got fresh fuel in it..it feels like it is running out of gas..kinda has me puzzled...normally if you have fuel and you have spark things run really well..this one hasnt decided to do that yet
     
  7. In no particular order of probablity, here's some wild-ass guesses to consider. It sounds like you're about to that point.:rolleyes:

    1. Is the fuel tank vented properly? Try loosening the gas cap when it's running poorly and see if it makes any difference. Fuel pressure is only part of the equation. You need sufficient fuel volume as well.

    2. Have you got a good accelerator pump shot when you open the throttle?

    3. Are you running an automatic choke, and if you are is it operating properly? Glad to hear you're running a heated intake, though that mainly affects cold driveability and helps prevent carb icing.

    4. Do the carbs have power pistons, are they recieving a proper manifold vacuum signal, are they moving freely, are the return springs in place, or are there metering rods that have the tips bent over?

    5. How much manifold vacuum do you have at idle?

    6. 700R4 trans...is it shifting OK? Trying to go into two gears at once? Trying to lock up the torque converter too early?

    Once you get to a certain point, you can't rule anything out with these these kinds of problems. Happy hunting!;)
     
  8. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    At this stage..i will check anything to see if it will make a difference..
     
  9. Unsafe6
    Joined: Dec 7, 2007
    Posts: 129

    Unsafe6
    Member

    Does it have points ign.? If it does put a new condenser in it. I chased a similar bog starve problem that I was sure was fuel related. Turned out to be a condersor breaking down. Felt like an idiot and was like no ign. symptom I ever encountered.
     
  10. twogees
    Joined: Jan 4, 2009
    Posts: 46

    twogees
    Member
    from Mid Mo.

    Just another guess at a possible problem, you said you replaced the fuel line. You might have sliced the inside of the fuel hose when sliding it over a hard line or fitting causing it to block the inside of the hose. This happened to me one time and had a hell of a time trying to find the problem.
     
  11. 68ragtop
    Joined: Aug 29, 2005
    Posts: 55

    68ragtop
    Member
    from Texas

    Where is the elec fuel pump located?.
    Most elec fuel pumps are designed to PUSH the fuel forward not suck fuel a long way to the engine. Also was said earlier is the tank vented, and what's the size of the line and where does the fuel get picked up at in the tank??
    Just ideas .......
     
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    I think ClayMart hit on something that gave me fits on my 51 Merc when I got it back together.

    Try running down the block and then if it stalls get out and loosen the gas cap. Then see if it will run ok. I went through three gas caps that were marked vented right on them before I got one that was actually vented.

    As far as the flooding during the intermediate cicuit operation, someone who knows those carbs might have to chime in with a solution.

    I checked the Weber site and a couple of forums that deal with those carbs.
    Those carbs have a power valve that may give trouble.
    Here is the breakdown http://www.racetep.com/weber/32_36DGAVEV.pdf
    The power valve is # 93.
    Weber site here http://www.racetep.com/weber/32_36DGAVEV.pdf
    A google search can provide more links.

    If it were mine I'd pull those carbs off and put a pair of small two barrel Rochesters or Carters on it.

    If you are hellbent on keeping those carbs I would suggest taking the rig to someone who specializes in working on them.
     
    Last edited: May 4, 2009
  13. Twisted6
    Joined: May 27, 2007
    Posts: 621

    Twisted6
    Member

    Also think about replaceing the coil and the pick-up could also be a heat up issue OR Under a load.
     
  14. bct
    Joined: Apr 4, 2005
    Posts: 3,154

    bct
    Member

    i'd listen to unsafe6....this guy knows his stoves...he helped a guy with the same problem last week on another message board...he nailed the problem and it was fixed pronto
     
  15. nexxussian
    Joined: Mar 14, 2007
    Posts: 3,240

    nexxussian
    Member

    Do you have a vacuum booster? I have heard of those going bad where after all the vacuum bleeds off they won't leak till you step on the brakes again (after the vacuum builds).

    ie Step on the brakes to put it in gear and instant vacuum leak.



    If the heat off the header getting to the intake is in question you can make a heat shield out of whatever metal you have handy (tin cans, roof flashing, really, whatever ya got handy) and tie wire it (temporarily) to the manifold to try it.
     
  16. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    First off i want to thank my brother Hambers for their help..it is greatly appreciated..i know if i am standing to close to the forest to see the trees one of you guys can show me the goofy thing..I thought i would give a little update as to what has gone on so far.
    I am still working out a bunch of bugs..the truck now has a total of 104 miles on the odometer..since this poor thing has sat so long i took for granted that all of the new parts would still be good on it..turns out assumption is the mother of all mess ups..I went back again to start at the fuel tank..i figured i am going to empty all of the gas again and double check to make sure nothing freaky was going on again..i disconnected the hose from the pressure regulator and kicked on the pump.

    A very weak stream came out into the bucket..what the heck this doesnt look right..i hooked it back up and the pressure guage was reading three pounds..so i unhooked it put the hose back in the bucket and the same thing..hardly nothing was coming out..i crawl under the truck and i hear the pump going at it..but i could also hear the sound of air sucking from somewhere..i finally find another section of fuel line i hadnt replaced with a split on the top of the hose..so now i am happy..replace this little section and it should be good..turn on the pump..still a weak stream in the bucket..i climb under the truck again follow the line from the back to the front and i find a clamp that is holding the hose to the frame and it has the hose pretty well smashed flat..aha!..i found it...got rid of the bent clamp..this has got to work..turn on the pump..nothing..and i mean nothing..grab hold of the hose and tried to blow through it...wrong..

    I disconnect the hose from the back side of the pump and i have gas..connect it..disconnect the front..no gas..something in the pump has froze up and i cant get a drop out of it..i find a cheapy electric pump i had thrown in my tool box and i hook it up..turn on the pump..and man i have fuel..all down the arm..soak the shirt and levis..now the wife doenst want to let me in because i smell like a gas station..note to self..tie down loose fuel line into bucket when you have a good pump..I thought man i have this thing whipped now.. started the truck..it sounded better took off down the road and nope fell on its face again..bummer..limped it back home got on the H.A.M.B. and there were some more ideas..

    Now the truck has an hei..with an accel module and coil firing this little beast..i read the post about the condensor might be bad..and i thought well i dont have points but what if by chance that accel module is acting up when it gets hot..got a stock module and coil and put the truck back together..fired it up and it sounded different..i thought different is good..i let it idle until it got up to temp and blipped the throttle..it didnt stumble..this is really good..i jumped in the truck and headed for the road..it didnt die!!..i am now stoked..i decide to take it out on the highway..she was purring right along..i am so happy i cant contain myself..get back into town and it still is doing good..i think i have the major problem solved..it wont stay running in gear at a stop light or a stop sign i have to kick it into nuetral so it wont die out..but it has come a long way from what it was..

    So once again i want to thank you guys..
     
  17. MXmaniac
    Joined: Oct 22, 2007
    Posts: 45

    MXmaniac
    Member
    from Denton, TX

    I had trouble with the Pertronix HEI kit on my 292, it had a stumble to it. I tried new distributor(with pertronix kit), new wires, plugs, coil, and nothing fixed it. Finally I replaced the whole set-up with a later model GM HEI distributor it ran silky smooth. It can be hard to find stuff that works better than stock.
     
  18. nexxussian
    Joined: Mar 14, 2007
    Posts: 3,240

    nexxussian
    Member

    Glad to hear it.:D

    FWIW if you haven't yet, that HEI dizzy will likely need a recurve as it should have a slow 'smog' curve in it with lots of total advance.

    I know it has helped immensly on every hotted up engine I have ever done it to, at least partly becaus it allowed me to run more initial without having excessive total.

    I think it was Mr gasket that used to put out a kit with wights, springs and limiter bushings (maybe even an adjustable vacuum can too?). Don't know if they still do or not.
     
    Last edited: May 6, 2009
  19. dooley t from okc
    Joined: May 3, 2009
    Posts: 5

    dooley t from okc
    Member
    from okc okla

    i had 1 chevy six out of several do this same thing . my engine builder swaped out the distributor (wore out shaft didnt fire right under load )had a bad wiggle in the distributor ..hpoe this helps ..builder said its the second one hes ever seen this with issue.. mine was a 235 six with updated hei distributor ...dooley
     
  20. jay
    Joined: Mar 3, 2001
    Posts: 438

    jay
    Member

    Well it is still rolling..doesnt like the stop signs..still stalls out..but once it is on a flat watch out..this is my first six and it is a blast..i am going to check the carbs this weekend..if you jump on it from a dead stop it has a stumble..i cant wait till i get all of the bugs worked out..i need to get some pics posted..i will see if i can borrow a camera this weekend too..
     
  21. Twisted6
    Joined: May 27, 2007
    Posts: 621

    Twisted6
    Member

    double check your timing and make sure the excel.pump is squirting.these could be your stumble problem???
     
  22. #1 Rule of Thumb: rule out the ignition before blaming the carb.

    Your stumble and fear of stop lights can both be caused by a lazy ignition curve. Also, when buying the parts to recurve make sure to get the adjustable vacuum can, it will never be happy without it.

    P.S. Follow the instructions, it may take some time and driving, but you will be glad you did!
     

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