Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Adjusted Valves. Need help ASAP!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Sparky, Sep 4, 2000.

  1. Sparky

    Sparky 1/2 ton status

    Joined:
    Aug 20, 2000
    Posts:
    423
    Likes Received:
    0
    Location:
    San Antonio(summer) Texas A and M (school year)
    I just finsihed adjusting my valves on my 78 Blazer with a 350. This was my first time to do it, and it got rid of the clicks that the valves were makeing, but I have a new problem. Now my truck is running like crap. According to my Haynes book it says to twist the push rod and tighten the rocker arm nut untill you feel some resistance on the push rod, and then tighten the nut another 3/4 of a turn. Is that the proper distance? That is what I did, but now my turck is running like crap. It stumbles at all throttle postion, and takes forever to pick up any kind of RPM. Does adjusting the valves throw the timeing or mixture off? Or, do I need to readjust my valves? Help as soon as you can. I need my daily driver. Thanks Again.

    Sparky

    78 K-5
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,173
    Likes Received:
    1,385
    Location:
    E-town baby!
    I back off the appropriate rocker until I know its good and loose, then I tighten the rocker stud until zero lash. This is where there is no more play in the push rod. At this point I tighten the rocker stud 1/2 to 3/4 turn. If you tighten until the push rod no longer turns in your fingers you could already have some preload. It sounds like you have over tightened your valves and they may not be completely closing, or they are barely closing. This would affect how much of the intake charge is being compressed before firing and how much is bleeding off.
    HTH, I did the same thing once[​IMG]
    Rene

    [​IMG]
     
  3. Sparky

    Sparky 1/2 ton status

    Joined:
    Aug 20, 2000
    Posts:
    423
    Likes Received:
    0
    Location:
    San Antonio(summer) Texas A and M (school year)
    Thanks for the help. You are the man! I guess off with the valve covers tomorrow morning. Should I completly redo all of them and go through setting the engine at top dead center again, or can i just back every one off a half turn or so?

    78 K-5
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,173
    Likes Received:
    1,385
    Location:
    E-town baby!
    Well when I did that I just started from scratch again, It does'nt really take any longer. Just make sure to follow the order of which valves to do and when to do them. It should be outlined in your service manual. If memory serves, I think you do half the valves at No. 1 TDC and the other half at No. 6 TDC. Check your book, I'm sure it is better than my memory.[​IMG]
    Rene

    [​IMG]
     
  5. Sparky

    Sparky 1/2 ton status

    Joined:
    Aug 20, 2000
    Posts:
    423
    Likes Received:
    0
    Location:
    San Antonio(summer) Texas A and M (school year)
    Yeah, it tells you what order. It is half at TDC. (half exaust half intake) then you switch to TDC of the exaust stroke, and do the rest. I guess I will not be lazy and do them all over again. Oh well, better safe than sorry. I just hope I dont need new gaskets again.

    Sparky


    78 K-5
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,173
    Likes Received:
    1,385
    Location:
    E-town baby!
    Yeah stuff like this usually happens after you finally get the valve covers to stop leaking[​IMG].
    I finally put some cast aluminum covers on because my tin covers were so far from flat that they leaked no matter what I did.
    Good luck
    Rene

    [​IMG]
     
  7. Thumper

    Thumper 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,582
    Likes Received:
    0
    Location:
    Alberta Canada
    I did the procedure by the book and ended up with the same problem. I couldnt even get it to run. If you have it running, Id take the covers off and do it while they are running. You just let it idle, loosen them off till they start clackin, then tighten them back up till they stop... then go 1/8 turn more.
    Good luck
    Mike


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Lets Go Wheelin! </font color=red>
     
  8. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    Thumper's method is the one I have always used also.Even after installing a new engine I'v re adjusted the valves in this manner. I just adjusted the valves on a firends boat with a new 350.It had one valve ticking and idled rough It runs great now. Ihe only drawback to adjusting the valves while the engine is running is you get oil on the exaust manifolds and it smokes a bit. I have a set of clips that cover the oil hole on the rocker arm that stops the oil from squirting everywhere. I bought then long ago but I think they still sell them at auto parts stores.

    [​IMG]
    Get Out and VOTE!
     
  9. jimmyjack

    jimmyjack 1/2 ton status

    Joined:
    May 11, 2000
    Posts:
    2,290
    Likes Received:
    0
    Location:
    Tucson Az
    I got an old set of covers from a yard sale for 5 bucks and cut the tops out so the rest of the cover catches the oil, no mess, no smoke!!!!!

    creepin' and crawlin'

    Jim
     

Share This Page