345 is shot - rebuild? or Find another?

Discussion in 'Hill Country Binders - Central TX' started by Gimlet, May 16, 2019.


  1. Gimlet

    Gimlet Farmall Cub

    Joined:
    Nov 16, 2013
    Messages:
    115
    Likes Received:
    16
    Trophy Points:
    18
    Location:
    Dripping Springs, TX
    Howdy folks. So, I've been having a coolant leak for a long time. I was going to address myself, but just haven't found the time to do so. Took it to the kind folks at Dripping Springs Automotive (formerly Pro-tech) and had them run a compression and leak down. Turns out, 4 of the 8 cylinders have very low compression (cyl 6 @55). They also found the culprit of my coolant leak - a freeze plug near the headers.

    So, I can fix juts the freeze plug and leave her as is. Or, I can have a machine shop do a rebuild... or, I can try to find a good 345 or 392 to swap in there.

    TBH, I've got a lot of money in this rig and don't use it nearly as much as I want to. I hate to spend $3-5k on her, when I'm honestly thinking about selling it next year. I would feel guilty selling it with a low compression motor however, and that would put me even farther away from trying to recoup some of my investment (I know there is no chance in hell I'll make it all back).

    What would y'all do in this situation? Anyone got a lead on a good running 345 or 392 (with intake and carb) that I can swap in?
     
  2. walkersscout

    walkersscout High Wheeler

    Joined:
    Oct 5, 2005
    Messages:
    1,469
    Likes Received:
    213
    Trophy Points:
    63
    Location:
    AZ
    I would redo the compression test, first dry, then wet. This will determine if it is valves or rings. If it is valves I would just have the heads rebuilt and be done. If the rings are shot I would consider a used motor, but I would want to see it run with a pressurized cooling system. Even then I would strongly think about pulling the heads and having a valve job plus a gasket set and freeze plugs.
    Also, I would not consider a used 392 and would be very leery of a rebuilt one. They have overheat issues that can plague you for a long and expensive time.
     
  3. Randall Barringer

    Randall Barringer Y-Block King

    Joined:
    Mar 4, 2004
    Messages:
    3,253
    Likes Received:
    485
    Trophy Points:
    83
    Location:
    baton rouge, louisiana
    There is a 345 (from a good Scout person) on facebook in/near Madisonville, LA.
    Good luck
    Randy
     
  4. Darrel

    Darrel Y-Block King

    Joined:
    Mar 14, 2002
    Messages:
    3,861
    Likes Received:
    590
    Trophy Points:
    113
    Location:
    Colorado
    A leak down would be even better. If a head rebuild wouldn't do it then a complete engine from S&J is less than $3,000.
     
  5. walkersscout

    walkersscout High Wheeler

    Joined:
    Oct 5, 2005
    Messages:
    1,469
    Likes Received:
    213
    Trophy Points:
    63
    Location:
    AZ
    You are probably right. I tend to fall back onto the tools I own, and I do not have a leakdown tester.
     
  6. Gimlet

    Gimlet Farmall Cub

    Joined:
    Nov 16, 2013
    Messages:
    115
    Likes Received:
    16
    Trophy Points:
    18
    Location:
    Dripping Springs, TX
    Leakdown was done as well and we determined the rings are shot. Haven't opened up the engine yet to see if there is scoring on the cylinder walls, but regardless, a small bore should likely be done. Essentially at that point a full rebuild.
     
  7. Darrel

    Darrel Y-Block King

    Joined:
    Mar 14, 2002
    Messages:
    3,861
    Likes Received:
    590
    Trophy Points:
    113
    Location:
    Colorado
    List it with the known issues and see if you get any bites?
     
  8. Gimlet

    Gimlet Farmall Cub

    Joined:
    Nov 16, 2013
    Messages:
    115
    Likes Received:
    16
    Trophy Points:
    18
    Location:
    Dripping Springs, TX
    I don't think I want to sell it right now, as it still has some other minor things that can be addressed. At this point, I'm either going to rebuild it or stuff a new one in there. I will update this thread with the resolution-
     
  9. Gimlet

    Gimlet Farmall Cub

    Joined:
    Nov 16, 2013
    Messages:
    115
    Likes Received:
    16
    Trophy Points:
    18
    Location:
    Dripping Springs, TX
    I've purchased a used 345 (thanks Sammy) and have taken it to a local machine shop to be built - JD Machineworks here in Dripping. I won't have the engine back until later in the Summer as the builder is back-logged a bit. As noted in Rob's thread, I'll be attempting the swap myself, and hope to learn from Rob's experience and the guidance of the folks here along the way.

    With that, I plan to address quite a few of the other minor issues too and get her back into top-notch condition to use her as intended for years to come.
     
    rustfreeTX and Mark Aycock like this.
  10. Hueste

    Hueste Farmall Cub

    Joined:
    Feb 27, 2009
    Messages:
    317
    Likes Received:
    36
    Trophy Points:
    28
    Location:
    Cut 'n Shoot, TX
    what are the plans for the old motor?
     
  11. Gimlet

    Gimlet Farmall Cub

    Joined:
    Nov 16, 2013
    Messages:
    115
    Likes Received:
    16
    Trophy Points:
    18
    Location:
    Dripping Springs, TX
    Once it's pulled it will be up for sale..
     
    Hueste likes this.

Share This Page