Opinions Wanted: Cracked Pistons, What to do....

Discussion in 'Diesel Tech' started by TulsaDiesel, Jun 8, 2018.


  1. TulsaDiesel

    TulsaDiesel Farmall Cub

    Joined:
    Jun 6, 2012
    Messages:
    37
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Tulsa, Ok
    Back story:

    A couple years ago my auto flex plate gave out. I have the SD33T bolted to a 727 auto in my 77'. Yes it was slow, but it was adequate. My truck came with the auto anyway and I got to upgrade to a turbo motor. I have the adapter plate top run the T-19, but don't have an actual tranny. If you are looking for this setup PM me. It was a pain in the ass trying to find that flex plate, btw. It is specific only to the SD33/727 setup. I ended up calling an Air Force NOS parts re seller. You did know that military issued Jeep CJ-10As used the same SD33/727 as our Scouts right?! I ended up getting the part for 15% of what a website was looking to get for their "last one in existence". Just FYI if your thinking about running an auto..

    Anyways, while I had the engine out I noticed the turbo was shot and the head was leaking coolant. Instead of slapping it back together and running it till it blew, I did the right the thing (maybe) and popped the head off to check for the notorious cracked pistons. Four out of six pistons were cracked, but still holding together. Here is where you come in...

    Option 1:
    Pending my liners look decent, I could replace the cracked pistons with the remaining good ones from overheated SD33 NA. I have 5 "good" ones..
    Cost: head/intake gasket & time (maybe a turbo rebuild)

    Option 2: Buy an 86' Craigslist SD33 that has been sitting. Info: seller has not heard engine run, previous owner bought at action, injectors and lines missing, injection ports "plugged" with something, but injection pump was left open to air.
    Cost: Engine purchase & time.

    Here is why: I have injectors (rebuilt) and lines form my original SD33. But, what about the injection pump being left open to air for who knows how long? I could swap my known running SD33T IP (rebuild my turbo) over and rebuild the turbo.

    Someone give me their opinion or save my marriage and come get my Scout...
     
  2. Joe S

    Joe S Farmall Cub

    Joined:
    Oct 27, 2011
    Messages:
    172
    Likes Received:
    11
    Trophy Points:
    18
    Location:
    Sunland, Lompoc, CA
    '86? What's it from? How much?

    Aren't the turbo pistons different? Five ring vs three?

    I think I'd buy a new set of piston/rings from Australia before counting on used stuff.
     
    Last edited: Jun 8, 2018
  3. TulsaDiesel

    TulsaDiesel Farmall Cub

    Joined:
    Jun 6, 2012
    Messages:
    37
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Tulsa, Ok
    The 86' is out of a Jeep CJ10A. Trying to talk the guy down to $500 delivered from Texas. He wants twice that.... Meanwhile I also found an entire CJ10A rolling chassis for $700. The injectors and lines are there, so no water ingress.

    I thought about new pistons/rings, but damn they are expensive...
     
  4. Joe S

    Joe S Farmall Cub

    Joined:
    Oct 27, 2011
    Messages:
    172
    Likes Received:
    11
    Trophy Points:
    18
    Location:
    Sunland, Lompoc, CA
    Even $500 seems high to me based on your description. The other one seems a better option if you have the room for it but anything not running is a crap shoot.

    If you do end up with a tug motor and you don't need it I really want the thermostat housing.
     
  5. TulsaDiesel

    TulsaDiesel Farmall Cub

    Joined:
    Jun 6, 2012
    Messages:
    37
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Tulsa, Ok
    I think I have an extra one of those. Is it the hose connection or the part that bolts to the block?
     
  6. Joe S

    Joe S Farmall Cub

    Joined:
    Oct 27, 2011
    Messages:
    172
    Likes Received:
    11
    Trophy Points:
    18
    Location:
    Sunland, Lompoc, CA
    The part that bolts to the head. Rectangular bolt pattern, thermostat fits in the top with the elbow on top of it. Not the same as the Scout part which has a straight up thermostat cover. The tug's is a 90* with a different bolt pattern.

    The one I have was corroded inside where the thermostat blocks off the heater flow. I made an insert to repair it but I needs welding and I'm not good enough with aluminum to risk it. If I can't find a good one I'll pay someone to weld it.

    Got a pic of what you have?
     
  7. TulsaDiesel

    TulsaDiesel Farmall Cub

    Joined:
    Jun 6, 2012
    Messages:
    37
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Tulsa, Ok
    The one I have is from a Scout...
     

Share This Page