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Replacing the heads on my 350... question

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Dave_S, Mar 30, 2002.

  1. Dave_S

    Dave_S Registered Member

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    I've cleared out everything around the heads (intake/exaust manifolds are off) and am getting ready to start removing the heads. Since I've never done this before, I'm not quite sure exactly how this should be done.

    Seems to me I'd want to take out the rods and then break the heads loose in reverse torque order then remove all bolts and take off the head.

    What isn't really clear to me is the best way to remove the rods. Do I have to take the rockers off? Or can I just rotate them.. and if I can... what happens to the spring on the other side.

    Dave
     
  2. 69K5

    69K5 1/2 ton status

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    Since you are just taking it off. Just take out the bolts it doesnt matter which order. When you put it back on follow the torque order. Whenever you undo the bolts just lift it up and the rods will still be in the block. There will be no reaction from the spring. hen take it to your machinshop and get them to do your heads/ valve jobs. If you want to take off the nut holding on the rocker. i think its 9/16. you will only be able to get tio certain ones because of the position of the cam and lobes.

    hope it helps

    nathan
     
  3. Dave_S

    Dave_S Registered Member

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    I was worried that leaving the rods in place may run the risk of bending them when I put the new heads on. I take it this isn't that much of a concern?

    Dave
     
  4. 69K5

    69K5 1/2 ton status

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    you'll just need two people . one to guide the head and one to guide the rods.

    nathan
     
  5. chevyracing

    chevyracing 1/2 ton status

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    Use a 5/8 sparkplug socket to remove the rocker retaining nuts. Remove the pushrods, but it is VERY important to keep them in the same order and put them back in the same location when you reassemble the engine. There are two bolts on the top of the heads that are resessed down inot a hole, don't forget to take them out. There are also three different bolt lengths. Note where they go. The springs are secured with retainers so no worry about loosing them. If after you get everything out and decide to pull the lifters make darn sure they go back into the same holes or you will destroy the cam.

    John
     
  6. Dave_S

    Dave_S Registered Member

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    I figured I'd have to put the lifters back into the same places... seems that's the best policy for virutally any part on a v8. I'll probably give pulling the head with them in place a try.

    Thanks for the help.

    Dave
     
  7. Steve_Chin

    Steve_Chin 1/2 ton status

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    I use a junk piece of cardboard with 16 holes poked in it to keep the pushrods in place (the term "rods" is usually used to describe the connecting rods). I just mark each hole in the cardboard with the cylinder number and E or I ans shove the corresponding pushrod into the hole in the cardboard, so that the rocker end of the pushrod is above the writing and the lifter end of the pushrod is below because installing the pushrods upside-down is just as bad as mixing up their positions. I leave the lifters in place and cover the valley with more junk cardboard.

    Don't forget that the head bolt holes on a Chevy Small Block break through into the coolant passages in the block so you will need to apply a flexible sealant to the threads of the head bolts when doing the install. GM/Rolls-Royce Hylomar sealant works well in this area, as does Permatex No. 1 Aviation sealant. Don't forget to chase the thread holes in the block with a tap to get any gunk out of them before installing the heads. Failure to do so will result in inaccurate torque readings when torquing the head bolts down.
     
  8. 72THING

    72THING 1/2 ton status

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    When replacing the head gaskets on my 350, I accidentally mixed up the pushrods because I took them out. End for end, side for side , etc. I mean they got really mixed up. Should I get some new pushrods? So far I haven't had any problems. What can be damaged by continuing to run this? thanks,

    Will
     
  9. chevyracing

    chevyracing 1/2 ton status

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    wear patterns on the pushrods will not be the same. In some cases it can cause the push rods to "drill" out the lifter or in other cases the push rods may not seat all the way down into the lifter at first, until it bores itself in (putting metal shavings into the engine) and then your valves will be out of lash adjustment. It can also cause them to not rotate. It will have the same effect on the rocker arm as well.
    In some cases nothing happens. (noticable anyway). But it is still an no-no.

    John
     
  10. Dave_S

    Dave_S Registered Member

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    OK.. I've pulled the pushrods out of the driver's side head. I just loosened the rockers and turned them out of the way. This also made the head bolts more accessible. The only problem I have now is getting a socket on the very back headbolt. The brake vacuum drum doesn't help much... nore does however many years of grime.

    I should have it off by tomorrow.

    On the bright side... the new ram's head exaust manifolds came in the mail yesterday. Nothing better than finding huge cracks in the manifolds as you remove them. About as fun as finding a crack in the radiator... oh... I found that too.

    Dave
     
  11. chevyracing

    chevyracing 1/2 ton status

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    sounds like you are jumping head long into the fascinating world of mechanics.

    John
     

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