frozen pistons need help

[crown]

 hi this moter is a cummins 8.3 94/95 model the moter got under water just got head off all 6 pistons
are stuck some still where 1/2 full of water HELP what can i pour in to cillinders to free up pistons
gasoline oil ? what also if cillenders are not pitted can i clean them ? thanks john ps bottom ends
looks good clean no rust ect head also looks good just some lite rust on valve heads

[Len Silva]

I would just fill them all with diesel and let it sit for a week or so, keeping the cylinders full of oil.  The a six foot cheater bar on the crank and try to turn it.  If it moves at all, go a 1/4" at a time in both directions, keeping it oil up.

If they don't move at all after soaking for a week, drop the crank and drive the pistons out one at a time. 

I have no real experience with the Cummins engine, I did it on an old Oliver tractor years ago, but it ran fine for a long time after.

[crown]

 hi how do i fill with diesel but then top off with oil john

[HighTechRedneck]

John, I don't have any experience based suggestions on freeing them up.  But when you do get them out, be sure to check the connecting rods and piston structures carefully for any kind of damage (bends, fine cracks, lines suggesting a crack starting, etc).  As I recall, it was driven into the lake (motor running) and efforts were made to start it.  And it is likely more efforts were made before you got it.  With water in the cylinders, it is a fair bet hydro lock occurred.

If it were me and budget permitted, I think I would assume damage was done even if I couldn't see it.  I don't know how the Cummins is built inside, but either new sleeves/pistons/rings/rods/bearings or bore out the cylinder to the next oversize and put in oversize pistons/rings and new rods/bearings.

[crown]

 hi mike it was not running when it went in lake  jack and i tryed to start it
but would not move right now the rings are froze and i need to loosen
them first to remove the pistons and rods the crank and lower end look
like new this moter had only 60.000 miles thanks john

[bevans6]

I did this once, with a car engine.  I used penetrating oil, soaked for a few weeks, head off, hammered on pistons with a big wooden block and a 2 lb hammer.  It eventually freed up.  Rings rust to the bores.  These days I'd do a complete rebuild, but back then I had to borrow the hammer...

Brian

[Len Silva]

hi how do i fill with diesel but then top off with oil john

I'm sorry, I was using diesel and oil meaning the same thing.  Just diesel or the penetrating oil of your choice. Doesn't matter much what you use, just keep it wet while you are working on it.

[TomC]

The Cummins 8.3 is a wet cylinder liner engine.  Once you have the cylinder head off, there will be nothing but the O-ring seals on the liners holding them in.  Hence, if you start hammering on them, or trying to turn them against them being froze up, you risk damaging the block where the liners seat.  Suggestion- pull the pan, take off all the piston connecting rod caps and individually pull as a unit each cylinder kit out of the block (cylinder liner, piston and connecting rod as one).  Once on the work bench, you can try hammering on them to loosen them up.  If it were me, I'd just chuck all 6 of the cylinder kits and buy new ones.  It will ultimately be the cheapest in the long run.  Then you'll not ruin the block or crank with turning it with a big breaker bar against the frozen pistons.  Good Luck, TomC

[crown]

  hi tom how do i remove do i just pull them out the bottom or push them out the top
do i need special tools to remove ? what do i have to be carefull with thanks john

[TomC]

John- mind you, I haven't done this myself, but when you pull the connecting rod cap off, with the cylinder head off, you should be able to tap up the cylinder liner and pop it out.  All that is holding it in is a couple of O rings.  Any questions above this, you should get hold of your Cummins dealer-or any others hear done this?  Good Luck, TomC

[bobofthenorth]

I've never done a Cummins but when we did our 466s we took the head off and then rolled the engine to push the liners out.  If he can't roll the engine then he can't do that which is going to complicate getting it apart because some of the holes aren't going to have the rods lined up for a straight push.  If it was me I'd still try rolling it with the head off.  Actually, if it was me, I'd be looking for another engine but that's another thread.

[NJT 5573]

I don't know about this engine, but back in the 80's Cummins went to a press fit liner. I doubt this engine is any different. If so you will need a liner puller or a bottle jack to remove the liners, they won't come out easy.

Chances are its just rust seized, but if it has been spun while hydro locked its real easy to bend a rod. They should be checked for straight if it was spun against the water.

I think its a waste of time to try and save the rings. I'd just beat the pistons out with some wood, inspect the parts, clean up the bores and install new rings. I doubt the pistons are real stuck, if they are, you might destroy the ring lands, so some oil of some kind would be benificial.

Usually if a block has been underwater it would be a good practice to pull it all the way down and tank the block to be sure all the oil passages are open. There are other ways you can check some of this, brushes, air, etc.

When the bearing caps come off if there is water present, I would at least use a brush on all the crank oil holes and what I could reach on the block. If the crank is rusty your gonna need to have it polished or polish it yourself. There is a fair chance the crank is stuck and not the pistons, it could be either way or both.

If you really need to pull the liners and they are press fit, its not real hard to make your own liner puller. You need to be carefull with a jack pushing a press fit back in, too much and you can break the block.

[hargreaves]

 What is most likley stoping the crank from turning is the pistons that are wanting to go down in the cyl. while trying to bar the engine over. The ones that want to go up will come out of the block with the liners. Disconnect the ones that will be going down and tap them out. put some fuel hose on the rod bolts so that you don't damage the crank.when those piston liner sets are out the other ones will come out as you bar the engine over.  AS far as freeing them up I would put the whole assy. in diesel fuel for a few days and then try tapping them out.  Good luck.      Gerry

[crown]

 update thanks for all the imfo this is what i known when we drained the oil clean clear fresh water came out first
  then black oil  the water pushed the oil up in the block / crank ect from the underside pan off looking up there
  is zero rust on linners crank rods rod bolts ect all clean and well oiled what i have done for now is i filled the
  clinders with diesel then with a scoth brite pad & 400 sandpaper i cleaned up the clinders and then put
  clean diesel back in and am going to let it sit till next week the head is also very clean but has lite rust on
  the valves thanks john  any more help you can give me post it thanks still got a long way to go

[gfcgfc1]

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