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Technical 235 cleanup/rebuild thread

Discussion in 'The Hokey Ass Message Board' started by oilslinger53, Sep 27, 2019.

  1. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    I’ve made a few posts about my lil project here, and decided to just go with one thread on the whole thing to document it all to help other amateurs who might be looking for advice. I’m not giving any advice, just looking for it, and leaving it here for future reference.
    So, I started out just installing dual exhaust, and tapping the crankshaft to eliminate balancer noise. Then I decided to paint the engine. THEN I figured I’d pull the head first.
    Long story short, the more I realized these engines are simple as f***. I’m down to a bare block, transmission at the shop getting a rebuild, and torque tube and rear end getting 3.55:1 gears and a complete rebuild. Just removed the pistons and crankshaft

    My question right now is, what’s you guys preferred method for cleaning cruddy pistons? Once I got em out I realized they appear to be aluminum, so I’m leery about using a wire brush. The rings also look to be aluminum. I was able to get this one off just using my fingers... is it aluminum? I’m not planning on replacing them because I think they look good. Sharp corners, no scratches on the flat surface that goes against the cylinder wall etc...
    But how would youz guys reccomend cleaning these pistons?
    [​IMG]


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  2. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Nevermind on the rings, just hit em’ with a very weak magnet. They’re steel. Pistons are aluminum though.


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  3. squirrel
    Joined: Sep 23, 2004
    Posts: 55,941

    squirrel
    Member

    The rings are cast iron, except for the oil rings, which are either steel or stainless steel. Being cast iron, they will break if you try to bend them too far, so be careful. But you probably want to replace them anyways, of course you'll want to hone the block, and before you get too far you'll want to measure the taper in the bore, and you'll decide that since it has .007" taper you probably want to rebore the block and get oversize pistons...and it never ends. That's why I suggested you just put it back together again, before you got it this far apart.
     
  4. we used to soak em in diesel fuel and brush with a firm plastic bristle brush
    we also used a ring grove cleaner
    re-hone and re-ring
    enjoy
     

  5. 302GMC
    Joined: Dec 15, 2005
    Posts: 7,856

    302GMC
    Member
    from Idaho

    Carb cleaner - the kind in a bucket, not the bomb can.
     
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  6. Budget36
    Joined: Nov 29, 2014
    Posts: 13,174

    Budget36
    Member

    I've good results cleaning piston tops with the 3m scotch pad. I'll see if I can find a link.

    No luck finding a good link, but basically a pad that I chuck in the drill.
     
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  7. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Thanks for the replies! Of course squirrel was right, I have new rings on the way. Taper is still good, barely .001 on the worst cylinder. So, new rings, deglazing hone, new bearings and back together she goes. Will update and post photos along the way.


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    Last edited: Sep 27, 2019
  8. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    6inarow, 302GMC and nunattax like this.
  9. You’re gonna do great,,,,,no problem at all.

    I always clean the pistons in some Berryman Chemdip if you can find it.
    The ring lands are what is most important,,,get all of that area clean,,and the rest can be cleaned by hand. It will help the rings seat back in very well,,,if the lands and rear area are clean. It lets the gas pressure get behind the ring and help seal it against the bore.

    Squirrel knew you wouldn’t be able to stop,,,Lol!

    Tommy
     
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  10. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

  11. s55mercury66
    Joined: Jul 6, 2009
    Posts: 4,335

    s55mercury66
    Member
    from SW Wyoming

    There is a ring groove cleaning tool out there, and they usually will fit several sizes of ring grooves. In a pinch, you can break one of your old rings, and use a piece to carefully clean the ring grooves.
     
  12. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    I’m taking the block to be hot tanked and having the deck milled flat, new rod bearings on the way, and a very slightly lumpier cam coming. I want to replace the camshaft bearings too since I’m putting a new cam. Figure why do all this work and leave the old camshaft bearings. These seem like a pain in the ass to replace. I should just have the machine shop install these, right? [​IMG]


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  13. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Also, this plug... I took this plug out and there’s nothing behind it. Just more cast iron. What’s behind the cast iron? Is it pressurized, or is it return oil? [​IMG][​IMG]


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  14. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

  15. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

  16. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Sorry for the weird double picture thing... don’t know wtf happened


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  17. That plug is the drain f0r the water jacket. once you hot tank the block the cam bearings are ruined. So by all means have the machine shop replace them. When you get the block back from the machine shop it will appear clean. It isn't. You need to run a rifle brush thru every oil passage. then wash it with a high pressure washer. blow it dry and spray it with WD 45.
     
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  18. Great to see a 235 being rebuilt. Great little engine. Can’t wait to see your progress. Love driving mine in my 53. Super reliable and a change from the usual 350 you see ...

    34FBB619-2236-49D2-B79B-8516FF5959BB.jpeg
     
  19. Camshaft bearings are not hard to install, but it requires a special set of tools. If you don’t build a lot of engines, have the machine shop that boils your block out do it. By all means, heed Oldwolf’s advice on using rifle brushes to go through EVERY passage with soap and water. Also use taps to chase all the threads in the block. Clean your head bolts off with a fine wire wheel. One day when my Babbitt banger 216 gives up the ghost in my 1950 3100, I’ll build a full pressure 235 for it.


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  20. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Is that better than WD 40?
     
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  21. With that plug out,,,,check a little closer.
    Take a screwdriver or something and push a little on the area behind the plug.
    It is sediment,,,looks solid,,,but it isn’t.
    That has been my experience anyway.

    Tommy
     
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  22. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Good advice, thanks everyone!
    @Old wolf- will make sure to scrub flush and oil every surface and hole on this thing


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  23. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Oh yeah, I must have been tired. Thats where the return water from the intake manifold heater is going to go.
    Thanks!

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  24. prpmmp
    Joined: Dec 12, 2011
    Posts: 1,129

    prpmmp
    Member

    About 5 more better:p! Pete
     
    Truck64 and Old wolf like this.
  25. You all never heard of a WD45 Allis Chalmers tractor?
     
  26. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    You know Cure 81 Hams are pretty dang good, it took 'em a while on them other 79 or 80 cures, I guess.
     
  27. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Dammit... I sprayed the block with wd45, but it was too heavy and crushed my block


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  28. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,500

    oilslinger53
    Member
    from covina CA

    Got my rings, but I see that the tops are cast iron. Mr. Tom says to avoid cast iron top rings, and to use moly or chrome. Anyone got a part# or lead for 3 9:16” plus .040 moly top piston rings? Or chrome if not?


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    6-bangertim likes this.
  29. I think your Ok with a cast iron top ring. You likely are not going to drive the car a couple 100,000 miles. the cast rings seat really good. and they don't wear the cyl walls.
     
  30. Iron is fine
    Unless ya put a lot of boost on it
     
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