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HELP- Rocker/Valve adjustment after cam upgrade

Discussion in 'The Garage' started by sr175, May 1, 2004.

  1. sr175

    sr175 Registered Member

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    Just upgraded my cam /forums/images/graemlins/peace.gif and am adjusting the rockers. Does anyone know when adjusting them after the motor is running and you loosen til it starts tapping and then retighten til it stops, do you just stop there or do you tighten a half turn or full turn after tapping stops?? /forums/images/graemlins/1zhelp.gif
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    loosen rocker until it is tapping at you then slowly tighten until no more tapping then 1/2 turn more. /forums/images/graemlins/thumb.gif
     
  3. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    never done it that way, way too messy.
    i always turn the motor over till the valve is closed fully, rotate pushrod until slight resistance (all slack is tacken up) and tighten 1/2 turn more, if hydralic lifters
     
  4. NerdBoy

    NerdBoy 1/2 ton status

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    [ QUOTE ]
    never done it that way, way too messy.
    i always turn the motor over till the valve is closed fully, rotate pushrod until slight resistance (all slack is tacken up) and tighten 1/2 turn more, if hydralic lifters

    [/ QUOTE ]
    I prefer that method, with one difference. I like to put a pre-oiler on my drill, and run the oil pump for a couple of minutes to get the lifters filled, before adjusting. It makes it easier for me to tell when the nuts are tight enough.
     
  5. ntaj*ep

    ntaj*ep 1/2 ton status

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  6. fortcollinsram

    fortcollinsram 1/2 ton status

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    To set it initially, like right after a cam install, I like to rotate the crank until the valve opposite the one I want to addjust STARTS to open. Like if you are running the #1 intake valve, rotate the crank until the #1 exhaust valve starts to open. Then loosen the rocker nut until the pushrod is LOOSE. Then while rotating the push rod tighten the the nut until you feel the SLIGHTEST ammount of drag. Then run the nut an additional 1/4 to 1/2 turn. Do NOT tighten the nut until you can't turn the pushrod anymore...This means that you have completey collapsed the lifter plunger and the valves will be WAY WAY too tight. If the initial adjustment works well I leave it /forums/images/graemlins/thumb.gif If not, I like to use the engine running method. You can buy clips that go on the back of the rocker to reduce the mess. I can ususally get one bank done in about 1-1/2 to 2 min with this method so the mess is minimal with the ening only idleing with one valve cover off...

    Chris
     
  7. gm4x

    gm4x 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    never done it that way, way too messy.
    i always turn the motor over till the valve is closed fully, rotate pushrod until slight resistance (all slack is tacken up) and tighten 1/2 turn more, if hydralic lifters

    [/ QUOTE ]
    I prefer that method, with one difference. I like to put a pre-oiler on my drill, and run the oil pump for a couple of minutes to get the lifters filled, before adjusting. It makes it easier for me to tell when the nuts are tight enough.

    [/ QUOTE ]

    Next time replacing lifters, chuck-up a piece of 3/8" wooden dowel rod in the drill press, get a (very) clean coffee can with about 3" of engine oil in it (enough to cover tops of lifters). One lifter at a time, set it in oil filled can and run the dowel into lifter to depress plunger (carefully, without jamming it) a few times, this will actually "bleed" the lifter. Priming the oil-pump is definately a great idea, but does little to "pump-up" lifters.
     
  8. sr175

    sr175 Registered Member

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    Well....It's done. It's running much better. Tried the haynes book method first to get running and then tried the running version. Ran into problems with the running way because I ended up having to loosen the nut up quite a bit before tapping would begin. Then when tightening til tapping went away and then 1/2 tighter the engine would stall. Went back to book method and all is well. Found half of a lifter on 7 exhaust worn in half and no lobe on the cam /forums/images/graemlins/eek.gif. Plenty of chunks of metal in the pan /forums/images/graemlins/eek.gif /forums/images/graemlins/eek.gif. Now the thing runs smooth like it never has /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/woot.gif /forums/images/graemlins/woot.gif
    The timing is at 8 now but have one other question. When giving it the gas it gives a pinging like sound. Any ideas?? I believe that usually this is because too advanced or lean? /forums/images/graemlins/dunno.gif

    Thanks for all the replies. /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif
     
  9. or2play

    or2play 1/2 ton status

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    You can buy these little clips that go on top the rockers. They defect the oil down instead of it flinging every where while you try to adjust the rocker. I think the same every time I adjust some. Damn this is gonna be a mess. And to top it off, having to smell the oil burning off the headers after I'm done.
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    To set it initially, like right after a cam install, I like to rotate the crank until the valve opposite the one I want to addjust STARTS to open. Like if you are running the #1 intake valve, rotate the crank until the #1 exhaust valve starts to open. Then loosen the rocker nut until the pushrod is LOOSE. Then while rotating the push rod tighten the the nut until you feel the SLIGHTEST ammount of drag. Then run the nut an additional 1/4 to 1/2 turn. Do NOT tighten the nut until you can't turn the pushrod anymore...This means that you have completey collapsed the lifter plunger and the valves will be WAY WAY too tight.

    [/ QUOTE ]

    I'm with you, although I NEVER adjust lifters with the engine running. Sorry old timers, but I just don't think this is the correct way to do it, so I do it with the engine off.
     
  11. 1-ton

    1-ton 1/2 ton status Premium Member

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    I think a running adjustment is the ultimate adjustment, but it is difficult to do with the newer center bolt heads without making a huge mess, or starting an oil fire.

    With the older style heads, I had a pair of stock valve covers, which I cut down, to keep oil off the engine while doing the adjustments. Then I used a set of those rocker arm clips to keep the oil from the push rods from flying all over the place. When I did the running adjustment, I would only tighten down the rocker arm 1/4 of a turn more, after it stopped clicking.
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I think a running adjustment is the ultimate adjustmento keep oil off the engine while doing the adjustments.

    [/ QUOTE ]

    If that is true, I've never read it anywhere in any service manual or on any installation sheet that comes with a camshaft.

    They have always said to do it with engine off so that's the way I've always done it. I've installed at least 5 camshafts in the last 3 years or so, and ALWAYS done it with engine off and NEVER had to re-adjust it afterwards.

    But, to each his own, if that's how you want to do it, great. A hydraulic cam doesn't care much anyway.
     
  13. burbBoy

    burbBoy 1/2 ton status

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    [ QUOTE ]
    The timing is at 8 now but have one other question. When giving it the gas it gives a pinging like sound. Any ideas?? I believe that usually this is because too advanced or lean? /forums/images/graemlins/dunno.gif

    Thanks for all the replies. /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Are you running vaccum advance on your Distributor? If so try disconnecting it. Some had very steep vaccum advance curves.
     
  14. 1-ton

    1-ton 1/2 ton status Premium Member

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    To me it is just a personal preference. You will never read in any official GM factory or aftermarket manufactures material an opinion on which is best.

    Back when I was a mechanic, I had a job maintaining a fleet of vehicles for about ten years, and about 1/2 of those vehicles where GM P30 chassis trucks with medium duty 350 V8's. Over those years, I had done hundreds of engine R&R's on those trucks. In the name of expediency, I never did a running valve adjustment on these vehicles, and they ran just fine; but with my own trucks, I was very detailed oriented, and did every thing I could to make my trucks perform as precise as possible.
     
  15. 1-ton

    1-ton 1/2 ton status Premium Member

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    [ QUOTE ]
    I like to put a pre-oiler on my drill, and run the oil pump for a couple of minutes to get the lifters filled, before adjusting. It makes it easier for me to tell when the nuts are tight enough.

    [/ QUOTE ]

    Right on! A man after my own heart... /forums/images/graemlins/thumb.gif

    You should try setting the ignition timing with a vacuum gauge and not a timing light. With an aftermarket camshaft, a timing light means nothing anymore because aftermarket camshafts, when machined, are not indexed to the crankshaft like GM OEM camshafts are. If you where to bring the number 1 cylinder, on your engine, to top dead center compression stroke, and used a degree wheel to find your camshafts true index to the crankshaft. I bet you would find the aftermarket camshaft to be as much as 4 to 12 degrees off of true top dead center.

    First, when you use a vacuum gauge, make sure it is connected to manifold vacuum. Second, advance the distributor until it reaches maximum vacuum (with an aftermarket camshaft this might be as high as 8 inches of vacuum or as little as 6 inches of vacuum). Third, back it off a half-inch of vacuum, and your done.
     
  16. sr175

    sr175 Registered Member

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    It is running vacuum advance. I will remove it and try. I am going to look at the fuel system next. I may have a couple problems there as well.

    My motor is a 1989 block thats been switched over to carb. I was planning to initially set it using the book method and then do the click test. The click test did not work to my surprise. Had to loosen the rockers way too much to get clicking and then when tightening the motor would stall and create other noises. I am definitey sticking to what the book says and also what comp cams says regarding adjustments. It WORKS (at least on my motor /forums/images/graemlins/waytogo.gif)!
    The good thing about having a destroyed cam and lifter is it provides a great paper weight for the desk at work /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif
     

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