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Engine gurus please help!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mofugly13, Jun 30, 2003.

  1. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    My engine now makes a horrible noise as son as I start it up. It sounds like someone is under the hood shaking up a can of spray paint, only MUCH louder. Like a loose rocker, but like I said MUCH louder. I have already replaced the rod and main bearings. While I had the oil pan off I tried to check for play between each rod and piston. I couldn't detect any. In the last few days it has gotten alot louder. When it started it was only after I reached operating temp, and I was criusing at highway speeds. Now itmake noise ALL the time. The flexplate is not cracked. So today I pulled the valve covers and put on some that I have cut the top out of so I can adjust the valves while the engine is running. When I fired her up I could hear the noise even louder. So I think it has something to do with my cam/lifters. But I don't know what. All the rockers seem to be rocking correctly, there is oil coming out of the top of the pushrods. The noise seems to be coming from inside the engine. Could my lifters be getting stuck so that when the cam lobe comes back around it smacks the bottom of the lifter? But the valves seem to be closing all the way. The engine seems to be running as smooth and strong as before the noise started happening, but I am afraid to stomp on it 'cause of the loud as noise. It soungs like metal to metal contact. While I'm idling the noise is going clack, clack, clack and every now and again theres a "screech" like a fingernail across a blackboard. This "screech" is a fraction of a second in duration and sounds like unlubricated metal rubbing on metal. My oil pressure is at 40 on the freeway and around 15 at idle. I can't drive my Blazer anymor until I get this fixed. Since this is my daily driver I now have to have my GF drive me to and from work and on roadtrips in her Jeep. Not that I don't like Jeeps, I have a frankensteined MB/CJ2/CJ3. But I'm 6'4" and leg room in the jeep leaves a lot to be desired. Besides the fact that I wanna drive my own ride. I'm saving for a GM crate 350, but for now I have to bandaid this one up to last a few months and a bunch of road trips during deer season. PLEEEEEZE! Does someone know what is going on?
    /forums/images/graemlins/usaflag.gif
     
  2. MousePowrd

    MousePowrd 1/2 ton status

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    Well, how long ago did you put this cam and lifter set in?

    When you pulled the rocker cover, they were all still adjusted properly? Not a single one was loose?

    My guess right now would be a bad main bearing, provided the rockers were all adjusted right.

    Provide more info on the engine build, why you replaced the mains in the first place, etc
     
  3. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    This is the story from the beginning \
    C'mon MousePowrd, send some wisdom my way bro. /forums/images/graemlins/thumb.gif

    I'm headed outside now to adjust valve lash by the book, ie. removing pushrod play plus one one turn. 'Cept my #7 intake which I only go 1/4 turn, utherwise it starts opening the valve.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Sounds similar to the noise my 350 is making. I've kind of concluded it's the timing gear hitting the timing cover from chain slop, as oil pressure fluctuates wildly when throttle position changes to idle quickly, then stabilizes. To me that says the oil pump is getting driven inconsistently.

    Mine sounds like a "clacking" noise too, but I've noticed no more oil consumption/burning, and no decrease in performance. The noise has progressed from just a quiet noise when cold only, to audible at higher RPM's barely, to loud all the time, audible in the cab.

    Riding my bike for now, waiting for the last few pieces to finish up the engine in the garage. Wish I had the noisey one apart, might be able to gain some insight.

    BTW, also heard of someones water pump giving off similar noises, but only one time have I heard that happening.
     

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