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Fun day of wheeling......and a few questions

Discussion in 'The Garage' started by 78Suburban, Apr 23, 2006.

  1. 78Suburban

    78Suburban 1/2 ton status

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    I wheeled the burb the hardest I've ever wheeled for about an hour or two today. The brakes feel like they are almost GONE, I have to put it all the way to the floor and pump it a few times. The motor is still running better than it was before I attepted to adjust the valves, but it did act up once or twice. It backfired through the carb ONCE, and stumbled ONCE. It also wanted to diesel evertime I shut it off. I had tons of fun though, I should have taken some actual wheeling pic, but never think to bring a camera. I would snap a pic of the burb, but its just a big muddy :burb: :p: ......
    I can't wait to correct the problems I encountered and go beat it again... I don't think 33" TSL's will break a corb 10, if it didn't break today... I beat it HARD :D
     
  2. MTChevy

    MTChevy 3/4 ton status Premium Member

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    i got nothing usefull to say, but thanks for the sig:D
     
  3. resurrected_jimmy

    resurrected_jimmy 1/2 ton status

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    I set a new personal best last week, broke the gov-bomb 10 bolt in an 03 Suburban with stock,original tires and 57,000 miles on it. I will never try and actually use a truck with a 10 bolt under it ever again.:rolleyes:
     
  4. 78Suburban

    78Suburban 1/2 ton status

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    http://coloradok5.com/forums/showthread.php?t=166667&highlight=dieseling+timing

    This thread had me thinking, I wonder if I need some octane booster. I think my timing is in the neighborhood of 10* BTDC. Can anyone think of any other problems? Could I have adjusted the valves wrong, or could that slightly worn stud I decided to leave be causeing any problems? The dieseling and the studdering I had once didn't bother me as much as the one backfire through the carb I encountered. Any ideas guys? should I throw some octane booster in the tank and see what she does?
    thanks,
    James
     
  5. MTChevy

    MTChevy 3/4 ton status Premium Member

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    your choke is working properly right?
     
  6. draggbody

    draggbody 1/2 ton status

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    i'll bet $100 that it needs a timing chain... theres your back fire, the dieseling, slow starting, poor performance, and all of it unpredictable...
     
  7. 78Suburban

    78Suburban 1/2 ton status

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    I dunno if you saw this thread:
    http://coloradok5.com/forums/showthread.php?t=169905&highlight=dorman+stud

    but That seemed to basically eliminate my terrible performace and backfiring... It only backfired once in 2 hours of wheeling.. the dieseling was new for today too.. I'm thinking my timing may be off or I may have too low of octane fuel. The backfiring could have also come from that #1 stud that I made the judgement call not to replace. Replacing the #6 exhaust rocker arm stud was a piece of cake, so if need be I can replace #1 (which was only slightly worn). I haven't 100% ruled out timing chain or cam lobe/lobes... but With how much improvement I gained from the above thread, I'm kinda leaning toward valve adjustment/ bad rocker stud.... The dieseling is what's really throwing me for a loop though.. :thinking:
     
  8. draggbody

    draggbody 1/2 ton status

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    so is it a bet???
     
  9. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    Sounds like you have a carb issue.. tho low octane can cause dieseling, it is usually a high idle or loading up issue from what I've seen mostly...

    this could also be the cause of your backfire...

    valves may be a tad tight, especially if you where running up the rpm's, but being it only did it once, I would suspect the carb..

    hot spots and wrong plugs can do it too, but I'd bet on the carb...
     
  10. 78Suburban

    78Suburban 1/2 ton status

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    so what should I do to the carb?
     
  11. draggbody

    draggbody 1/2 ton status

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    so is this one of those situations where you only want to hear the answer you want to so that you can talk about fixing this forever and never acctually get around to fixing it... it is obvious that you got a worn engine, rocker studs??? so if it has never been changed the problem is not going to get better.... pull the dang cover off and if it is not the chain i will pay for any gaskets, coolant, motor oil, etc. that you have to buy.... you said you already tried anther carb, so what do you have to lose???
     
  12. 78Suburban

    78Suburban 1/2 ton status

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    WIll you really pay for all that stuff, it adds up quick :p: . Yes its a POS motor that I got from a ck5er who royally screwed me over, but it beats the 5 oil psi turd I pulled out. Whats to make it be more apt to be a timing chan than a wiped out cam lobe? Or just maybe not adjusting the valves correctly yet? They were so rediculously loose that I couldn't believe it. Literally less than 0 lash. It runs light years better for having replaced the severly worn stud and readjusting the vavles. I just don't know how it would be for sure a bad timing chain as opposed to wiped out cam lobe, dead lifter, chipped valve, ect.......
     
  13. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    She'd barely run at all with a bad timing chain. My guess is one of five possiblities, in reverse order of their likelyhood (in my opinion):

    5th) Mixture is too rich, causing dieseling, but not likely causing the backfiring

    4th) Idle is too high, causing the dieseling, but not likely causing the backfiring

    3rd) Valves are mildly out of adjustment, causing the backfire, but not likely the dieseling

    2nd) Timing is too advanced, which causes backfiring through the intake and dieseling

    1st) A combination of two or more of the above four possiblities
     
  14. pvfjr

    pvfjr 1/2 ton status

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    I'd say check the carb too. And yes, draggbody, he already tried another carb, but that was when his valves were hosed. You can't tune or check carb problems if you don't have properly operating valves.

    James, I think the easiest thing to check right off would be your idle mixture and speed. That *could* account for your dieseling. But I'd run through and check all the other adjustments on the carb too, along with setting the timing and checking the condition of your plugs. They could've gotten screwed up during all the chaos and the motor not running properly. I'd also tear the cap off your dist, and look at your mechanical advance weights and springs. Make sure they're not all rusty and gummed up, and make sure the springs look like they're still functioning. I'd also check the vacuum advance and make sure it's working properly. That could account for your stumbling. It could be an accelerator pump too, make sure that is adjusted right.
     
  15. draggbody

    draggbody 1/2 ton status

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    is this timing chain like the holy grale of mechanics.... i mean this is a days worth of work, but if the mechanical timing of the engine is incorrect then no amount of adjustment will "fix" the problem, and yes most engines will run w/ a worn chain, i bet 75% of the people on this board have worn timing chains, not to say that they are on the verge of failure, but that they are not as good as they should be...
     
  16. 78Suburban

    78Suburban 1/2 ton status

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    I forgot to mention, it was running warmer than normal, got up to about 210 or 212*. After a long MSN conversation with SierraClassic, I'm betting that I was running very lean. This carb ran great on my old 283, but I bet the 350 needs some more fuel. The backfire did occurr at WOT. A lean condition could also account for running warm, and it could also make carbon deposits glow and cause dieseling. I'm gonna pull a plug and see what she looks like. If ya remember, my plugs were getting coated with carbon deposits when all of the valves were adjusted waaaaaaayyyy off. If I was running lean yesterday, and the plugs already had a lite coating of carbon, would running lean burn/clean all the carbon off? I'm just trying to make sure that reading a plug will actually tell me something in this situation.
    thanks,
    James
     
  17. 78Suburban

    78Suburban 1/2 ton status

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    running lean

    Well, as you all know, the plugs were very black when I was attempting to drive it with horribly misadjusted valves. Not that I've adjusted it, it has shown symptoms of being lean such as: running too hot, dieseling, stumble at WOT, lean backfire at WOT. You have to remember, my edelbrock performer 600 cfm ran perfect on my old 283, but on this 350 appearantly its not providing adequate fuel.

    [​IMG]

    [​IMG]

    Lean plugs look white, right? its as if all the carbon deposits were thoroughly burned off. Wonder how many steps richer metering rods I need to order? Does summit sell a set of different rods? How do I tell what rods I have? I can also borrow a vaccume guage from a buddy, that will help me fine tune the Idle Mix Screws.

    Any votes that I'm running lean :confused: ?
    thanks,
    James
     

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