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    Author Topic: GMC problem  (Read 2228 times)

    Offline tactransman

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    • 1973 Challenger- Member here since April 14, 2006
    Re: GMC problem
    « Reply #15 on: August 21, 2007 - 12:43:59 PM »
    Quote from: Chryco Psycho on August 17, 2007 - 02:05:08 AM
    I have seen the oil pump pick up tube fall into the oil pan & starve the engine for oil on a few 4.3 engines , they are just press fit , no threads or welds to hold them in
    Isn't it amazing, that was a problem in the old days and they never did (or took so long if they did) to correct it. :crazy:
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    Terry-tactransman 
    Torqueflite/Automatic Transmission Specialist
    Union, Mo.
    Give a man a fish and he eats for a day,teach him to fish and he eats for a lifetime.


    sleepychallenger

    • Guest
    Re: GMC problem
    « Reply #16 on: August 21, 2007 - 02:30:10 PM »
    i was sick this past weekend and am just now getting over it so i havent been looking at this thing. but i did have plenty of time to think.... with 115K or so, what about the timing chain?
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    Offline Oldschool

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    Re: GMC problem
    « Reply #17 on: August 21, 2007 - 08:11:32 PM »
    Sleepy,
    Can you tell if the knock is 1/2 speed or not?  If it is knocking very fast with the lower end, you might look for piston slap or rod, or wrist pin.  Anything in the lower end.  If it is knocking every other stroke, or 1/2 speed, it is in the top end.  Remember the cam turns at 1/2 of crank speed.  Another thing is pull a spark plug wire one at a time while it is running and see if the noise changes. Basically, you are selectively killing each cylinder.  Sometimes the lack of pressure on the top of the piston when the cylinder fires will quieten it down.  Anyway, there are several ways to help diagnose this.  Hope this helps a little bit........    :cheers:    :cooldancing:   
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    Ken  --  In Georgia

    MOPAR-------"Built To Run------Here To Stay"

    Offline ntstlgl1970

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    Re: GMC problem
    « Reply #18 on: August 21, 2007 - 09:01:25 PM »
    Quote from: sleepychallenger on August 17, 2007 - 02:24:24 PM
    will have to check when i get home. this thing has the vortec motor, just dont know what the dif is. i used to work at ford as a tech, never really looked at anything gm.

    Did you ever get the vin #
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    70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

    sleepychallenger

    • Guest
    Re: GMC problem
    « Reply #19 on: August 22, 2007 - 02:21:50 PM »
    Quote from: Old's  Cool on August 21, 2007 - 08:11:32 PM
    Sleepy,
    Can you tell if the knock is 1/2 speed or not?  If it is knocking very fast with the lower end, you might look for piston slap or rod, or wrist pin.  Anything in the lower end.  If it is knocking every other stroke, or 1/2 speed, it is in the top end.  Remember the cam turns at 1/2 of crank speed.  Another thing is pull a spark plug wire one at a time while it is running and see if the noise changes. Basically, you are selectively killing each cylinder.  Sometimes the lack of pressure on the top of the piston when the cylinder fires will quieten it down.  Anyway, there are several ways to help diagnose this.  Hope this helps a little bit........    :cheers:    :cooldancing:   

    I took the stethoscope to the timing cover and it was knocking through there. i checked the bottom end and it wasnt through there. I tried the plug wire thing and that didnt make a difference. couldnt pull the harmonic last night because i had the wrong size puller. GRRR this thing is pi$$ing me off. No wonder i will not ever own a GM product. Even my fords were not this bad.  :poopoke:
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    sleepychallenger

    • Guest
    Re: GMC problem
    « Reply #20 on: August 22, 2007 - 11:19:45 PM »
    Quote from: ntstlgl1970 on August 17, 2007 - 02:22:59 PM
    What is the 8th digit of the VIN? W or Z


    w
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    Offline ntstlgl1970

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    Re: GMC problem
    « Reply #21 on: August 23, 2007 - 01:41:18 AM »
    Vin W is the CPI motor. Did the noise just start recently or has it always done this.....

    In the bulletin, I know you said that the RPM range was wrong, but the bulletin specifically mentions noise from the timing cover/balance shaft drive area. The balance shaft wouldn't be affected by ignition wires being pulled.

    Can you tell if it is crankshaft speed or engine speed?

    « Last Edit: August 23, 2007 - 01:56:19 AM by ntstlgl1970 »
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    70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

    sleepychallenger

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    Re: GMC problem
    « Reply #22 on: August 23, 2007 - 01:51:40 PM »
    cant tell, engine is torn apart now so i can not hear it, timing chain has lots of slack. about 1/2 inch on one side and about 1/4 inch on the other. i can grab the gear on the front of the balance shaft and it does move a little but not much and not up and down, just barely back and forth
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