1969 GS 400 pushrod & rocker help

Discussion in 'Race 400/430/455' started by Junkyardog, Aug 15, 2018.

  1. Junkyardog

    Junkyardog Member

    Guys... I need a bit of guidance from experienced engine/head guys...

    I have a buddy that is an original owner of a 1969 GS 400 conv 4spd and over the weekend he bent a pushrod. Don't know why, but now we have to figure out what to do...

    I need pictures of a new or slightly worn pushrod end to see what the ends should look like. On his, the lifter side has a flat spot where it touches the lifter and the rocker side has a divot where oil might sit. The divot doesn't look right... I just don't know if it's so worn that all need to be replaced. Also, the bent pushrod rocker (cylinder #3 exhaust) has a small missing piece on the pad there it touched the valve and was wondering whether I should replace it or not. (I most likely will) Lastly, can you take your palm of your hand and pound on the valve stem and get them to move meaning depress the valve into the head everso slightly to hear the valve clank? Each valve does it and I'm thinking those springs are worn.
    The engine may have 15K miles on the rebuild, but not sure what kinda rebuild he got done. They might have used original worn springs... His car has over 300K miles on it and had been very well maintained...
    Any help in the right direction would be wonderful... part # of pushrods, part # of lifters, etc... Thanks a bunch... Mike
    gsconv likes this.
  2. Junkyardog

    Junkyardog Member

    Is anyone out there a Buick engine expert..??? ANYONE??????? I still need help on my push rods...

    We're about to pull the heads on my GS... Did a compression test on the problem cylinder and get ZERO.... Not too good..!!! I looked thru the spark plug hole with a scope and saw shiny metal on the top of the piston. I bet I bent a valve... :-(
  3. gscalifornia

    gscalifornia Small blocks rule!!

    Though I'm not a Buick engine expert I do have some NOS and used push rods. I'll try to remember to take some pictures of each end this evening and post them tomorrow. Yes, the pad should be replaced on the end of the rocker. If that pad broke it may have been the cause of the bent push rod. I'd be looking for the pieces of the pad before they wedge someplace bad. You can remove the whole rocker assembly and slide the rockers to the side to see how work the shaft is getting.
  4. Junkyardog

    Junkyardog Member

    Thanks Ken for responding... I was getting worried no one was out there to assist...

    I was looking at the head last night and actually found the broken piece of pad. That was a load off my mind... All of the rockers easily move, so I think it'll be fine. I'm gonna have my engine guy that is going to do the heads look at it for me. I would assume the push rods are available, right..? Mike
  5. BrunoD

    BrunoD Looking for Fast Eddie

    Well,in case you do need them,I have a full set of NOS 69 push rods, still in the original Buick package.I might have a few used ones also,that I'll have to check it out.If you need them,send me a PM.Bruno.
  6. gscalifornia

    gscalifornia Small blocks rule!!


    This is a picture of the pushrods I have that are marked '69 GS400. I bought them from a board member in Washington for a '69 GS convertible that is still stuffed in the back of my garage. Then ends are perfectly round.
  7. Junkyardog

    Junkyardog Member

    Thanks Ken. The very ends of our pushrods have flat spots and divots/craters on them. They must have taken a pounding over the years.
    The heads and rockers are at our machine shop right now. I'm waiting to see what is up next.

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