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Thread: Seized Diesel engine.

  1. #1
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    Default Seized Diesel engine.

    The boat's been out of the water since September 2016, with the engine being removed a week or so later, and put into my garage for some work. In the garage I did completely flush the cooling system, which is the most simple direct cooling. However, I didn't remove the injector and put in oil, or spray WD40, nor did I regularly 'turn over' the engine from the flywheel, although I did move turn it 'a bit' in January. Now, the engine's back in the boat and the piston has seized.
    This being the case, I've now removed the injector and filled the cylinder with diesel, and left it alone for 3 days. This morning I tried to manually turn the engine, and there's been no change, it's still bound!
    I've got another 40 days to go before we 'crane in'; so can any of the very clever folk here, suggest anything for the next fortnight (2 weeks), that I might attempt, which may help?
    After this 2 week period, if the engine's still seized, then I will probably take the head off, and try to give it a thump, but I'd like to avoid that.
    The engine's a Renault RC8D, from a previous era, but in very good condition, except for being seized internally! The engine was completely rebuilt prior to fitting last year, and ran perfectly all season, all around Scotland, thus I'm convinced that this isn't a terminal issue, however alcohol is helping with this opinion!

  2. #2
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    Default Re: Seized Diesel engine.

    In the US they (we) use something called "Marvel Mystery Oil", it is really called that and it's good. I am not sure if you get it in Scotland.

    I've never tried it, but the tests always show a mixture of transmission fluid and acetone to be the best easing oil.

    I'm guessing that you've already tried a socket on the crankshaft nut and a lot of leverage.

  3. #3
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    Default Re: Seized Diesel engine.

    "Thumping" the piston does not sound like a good thing to do.
    The flush of the direct cooling system ... a few drops may have entered the cylinder through a valve. The smallest bit of rust on a ring has locked up a small engine of mine. And it messed up the cylinder wall that it needed burnishing.
    A LOT of leverage, like an 8 foot pipe .
    Employ magic words to compliment the alcohol!

  4. #4
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    Default Re: Seized Diesel engine.

    Hmmm, ..... Only six months since being turned over??????? Something is going on that is not quite right. six months isn't even a nap. Six years (or more than twice that) may cause an issue, but six months on its own should do nothing.
    It sounds like this a salt water cooled engine (sea water through the water jacket). Did you leave the water jacket empty with only air in it, or after flushing did you fill it with anything (antifreeze).
    How old is the engine?
    (I will point out that if it is an older engine - and with the water jacket partially obstructed by rust buildup- that six months of exposure to the air may have accelerated the rust buildup in the cylinder to that point that the rust has filled the water jacket and has now compressed the cylinder a bit to the point that the piston is stuck. Seems very unlikely for this to happen in only six months, but this certainly is an issue and concern with old salt water cooled engines that have been out of service for a long time. - It is best to store them with the water jackets full of antifreeze (or in days past they used to fill the water jackets with old crankcase oil)).
    I hope it is something simple like a stuck ring.

  5. #5
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    Default Re: Seized Diesel engine.

    I owned a boat with a Lister diesel that had been standing for 8 years and siezed solid. I tried the lubricant down the bores and the scaffold pipe with no luck. Having decided it was probably scrap, i did not feel guilty about pounding the starting handle with a sledge hammer, which finally freed it. Started on the second attempt, i was dumbfounded.
    I do not reccomend the above method, it certainly sounds like a ring has probably nipped up with corrosion, if it has only been standing for that short amount of time, then penetrating fluid and a scaffold pole should free it.

  6. #6
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    Default Re: Seized Diesel engine.

    My 2 cents: get access to the piston tops, and soak them in penetrating oil of some kind for a week. Then use a block of wood, hold it to the piston, and tap it with a hammer to break the rust grip at the rings.

    After you get it to run for a minute or so, change the oil and filters. Flush out the sump. Get the rust removed.

    As said, the cylinder liners may become scored this way, but rust is rust and the damage is already done. (It'll probably be OK.)

  7. #7
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    Default Re: Seized Diesel engine.

    If you use the acetone and ATF as penetrating oil the acetone will make it down into the crankcase where it will eat up the main seals.

    I agree with the socket on the crankshaft nut strategy.

    Does it have a starter/generator? Is it seized?

  8. #8
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    Default Re: Seized Diesel engine.

    i have had good luck freeing up a couple stuck motorcycle engines using gentle heat on the cylinder head plus a homemade penetrating solution of acetone + automatic transmission fluid (1:1 ratio)

    then get a socket + long breaker bar on the crankshaft pulley if accesible

    i would only pound on the piston as a last resort for fear of punching a hole through it or breaking a ring

  9. #9
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    Default Re: Seized Diesel engine.

    If it does free up, make damn sure you get out ALL the diesel you poured in, before refitting the injector. Get this wrong, and hydraulic (hydrolock?) the motor, you are likely to bend the conrod.

    Pete
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  10. #10
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    Default Re: Seized Diesel engine.

    Let's see a photo of this old mill. Does it have a compression release thingy for the exhaust valve?

  11. #11
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by wizbang 13 View Post
    Let's see a photo of this old mill. Does it have a compression release thingy for the exhaust valve?
    That has me wondering if a valve could be seized open and the piston hitting up against it. Might be a good idea to remove the head and have a look before putting too much force into it. I don't know the layout though, perhaps you have or can find a schematic view.

  12. #12
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    Default Re: Seized Diesel engine.

    I don't mean pound the piston. Just a firm tap. Around the edges if possible.

  13. #13
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by Dave Hadfield View Post
    I don't mean pound the piston. Just a firm tap. Around the edges if possible.
    While someone else mans crankshaft nut.

  14. #14
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by Gib Etheridge View Post
    That has me wondering if a valve could be seized open and the piston hitting up against it. Might be a good idea to remove the head and have a look before putting too much force into it. I don't know the layout though, perhaps you have or can find a schematic view.
    yup, if it is a simple one cyl, the first thing is to pull the head, I would not even pull the stinking injector. They can be more temperamental.

  15. #15
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    Default Re: Seized Diesel engine.

    I dunno if a piston can hit an open valve,who would design that? Unless the stem breaks.
    The potential of the mill bending its crank from hydraulicing is very teal, if the exhaust valve can be locked open , I recon one could just spit the soaking oil out with the fast spinning starter. A GLORIOUS mess!!!
    jebus, I learned more than I ever wanted to know about this crap with my Ducatis

  16. #16
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by wizbang 13 View Post
    I dunno if a piston can hit an open valve,who would design that? Unless the stem breaks.
    The potential of the mill bending its crank from hydraulicing is very teal, if the exhaust valve can be locked open , I recon one could just spit the soaking oil out with the fast spinning starter. A GLORIOUS mess!!!
    jebus, I learned more than I ever wanted to know about this crap with my Ducatis
    Loads of engines - I would venture to suggest most in fact, are what are termed interference engines. Lose the cam belt/chain/gears or get a valve stuck open, and the piston will have an unfortunate meeting of ways with any valves that happen to be open.
    Most Toyota automotive engines with cam belts, are non-interference, and wont trash themselves if the belt breaks. They are one of the few exceptions though.
    However, even if this particular engine had this problem, that wouldn't stop it turning the other way, close to a full turn, so I would say it is extremely unlikely that it has the piston hitting a stuck valve, as it sounds like it is completely siezed.
    And I agree with the earlier post, that six months in storage is nothing, unless it got a dose of water down the bore accidentally.

    Pete
    Don't underestimate the power of stupid people in large numbers!

  17. #17
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    Default Re: Seized Diesel engine.

    Pretty much standard on diesel engines, as the compression ratios are much higher (hence clearances are a lot tighter)
    my plan would be
    1 Pull the rocker cover off and check the valves are free
    2 Soak with diesel, as you already have, but leave for a week at least.
    3 Pull the head off, head gasket shouldn't cost that much

    problem is, that if it has seized and you free it off, who knows what problems are lurking, corroded bores etc that will cause problems further down the water, being as you only have one cylinder, you really want it to work.

    Quote Originally Posted by wizbang 13 View Post
    I dunno if a piston can hit an open valve,who would design that? Unless the stem breaks.
    The potential of the mill bending its crank from hydraulicing is very teal, if the exhaust valve can be locked open , I recon one could just spit the soaking oil out with the fast spinning starter. A GLORIOUS mess!!!
    jebus, I learned more than I ever wanted to know about this crap with my Ducatis

  18. #18
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    Default Re: Seized Diesel engine.

    I believe this IS an interference engine. Per a manual I found here: http://www.stw.fr/download/docs_moteurs/RenaultRC8D.pdf See Pg 14

    It seem the valves are flush with the bottom of the head & the piston comes up to within less than a mm of the top of the block & the head gasker is .4-.8mm. No way the valve only opens 1.5mm or so.

    That being said - what would make the timing jump when the motor's been in storage?

    From the manual, removing the head does not look like too bad a job. If it were me (& I'd had a few days/drinks to fortify myself), I'd pull the head & soak things down well. As mentioned above, acetone can destroy seals + it's nasty stuff, so I wouldn't use it. I would use Marvel Mystery Oil or auto trans fluid to soak down the rings for a few days, then try to turn the crank.

    My 2 cents...
    "If it ain't broke, you're not trying." - Red Green

  19. #19
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    Default Re: Seized Diesel engine.

    Step one is pull the head off that little guy and have a look.
    Ratus ratus bilgeous snipeous!

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  20. #20
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    Default Re: Seized Diesel engine.

    I once pulled the head off of an engine that had been sitting around for a while with the exhaust valve in the open position. The valve stem had rusted into the guide and the piston hit it right away when I tried to start it. It can happen.

    Ever since then when I shut down a small engine I give it enough of a pull that it comes up against compression to make sure that the exhaust valve isn't open and allowing the ingress and egress of moist air. Makes sense, really.

    Pete makes a good point though, if you haven't tried turning it over in reverse that would be a good diagnostic tactic.

  21. #21
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    Default Re: Seized Diesel engine.

    Pull the head. It will be pretty easy. Then a little heat applied around the perimeter of the piston and a wack with a mallet you will be good to go. Might polish the cylinder afterwards with one of the drill attachments. I got a BMW running this way that was seized for 20 years.

  22. #22
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    Default Re: Seized Diesel engine.

    Many thanks for all of the good advice. The state of play is that because I've presently got time, I'm able to be patient, and will just see what happens with the diesel in the bore. When I mentioned that this is from an earlier era, it wasn't an understatement. There's no oil pump, as it's a splash lubrication engine! The injector pump isn't on the head, it's about a foot/15cms. away, on the lower side of the engine, what I'd imagined as 'a pressured injector', is really only a tube fitting, connected by hard piping to the pump; I believe that this is somewhat unusual these days. The basis of the engine is from a cement mixer, general construction unit, and it's designed to run in a fairly unstressed and unmaintained manner, with the paint being the most sophisticated thing of it!
    To remove the head shouldn't be too dramatic an event, as on my boat it's quite accessible, (there's that booze kicking in again!), and would then give the piston a thump using a wooden block to preserve the piston. Getting a spare gasket is easy from French supplier.
    I'll post again when something's occurred, and it's hopefully running.

  23. #23
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    Default Re: Seized Diesel engine.

    Good luck & do let us know!
    "If it ain't broke, you're not trying." - Red Green

  24. #24
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    Default Re: Seized Diesel engine.

    Remove the injectors, squirt some light lubricant, like Kroil into each cylinder. Then, I would try removing the starter and using a bar to engage the teeth on the flywheel. This will give you tremendous leverage. If you can't move it that way, you probably can't move it.

  25. #25
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    Default Re: Seized Diesel engine.

    If the above lubricant based suggestions (they are better in the long run) don't free the engine then I would/have introduce some white vinegar in the cylinder through the removed injectors port and let it sit a few days. The vinegar will dissolve the rust. After you have waited what you deem an acceptable amount of time try to free it using an impact wrench and socket on the crank pulley snout; with the injector still out.

    Once the crank starts to move even a tiny bit put oil into the cylinder immediately so that you don't score the liner walls because vinegar is not a lubricant. Once it seams relatively free change the oil and start it. As mentioned above make sure that all liquids are out of the combustion chamber before you try turning it over with the injector.

    I have used both Mystery Oil and vinegar many time on stuck antique engines. I prefer Mystery Oil to vinegar but it is slower.

    Good Luck.
    Last edited by leop; 03-21-2017 at 07:56 PM. Reason: stupid auto spell check mangled it

  26. #26
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    Default Re: Seized Diesel engine.

    That is a cute little engine and I hope you are successful.
    You can easily generate over 1000 foot pounds using a lever, even a large screwdriver against the ring gear, and I have had good luck with that. (I was once hired to "Free-up" a small marine diesel that mysteriously "siezed" and found a bolt tightened into the cam timing gear. Someone had noticed a bolt not tightened and ran it in tight, effectively locking up the engine. Which is procedural on many diesels to set the pump timing... a "tool" included in the design of the engine similar to a Model A Ford. That one was easy money!)
    Aluminum pistons with Iron rings and a little bit of sea water do resemble a battery and electrolysis sets in very quickly.

    This one?
    edit; It looks a lot like the little BMW 7 hp (Which is actually a rebadged marinized Hatz)

    Last edited by Canoeyawl; 03-18-2017 at 07:13 PM.

  27. #27
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    Default Re: Seized Diesel engine.

    Occam's razor says that the most likely cause is stuck rings, just as you are thinking. But I agree with the other people saying that six months seems far too short for that to happen. And given that you have had the engine out and reinstalled I would also look for other things that might be causing problems. Is there a problem with an ancillary component that could be keeping the engine from turning over? As an example, I was sure that the Detroit 3-53 in my boat was seized. It had been partially submerged and then sat for over a year, and it didn't budge at all when I put a breaker bar on it and tried to turn it over. But further inspection showed that the problem was actually a frozen, belt-driven hydraulic pump. After taking off the drive belt for the pump the engine turned over with no problems.

  28. #28
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    Default Re: Seized Diesel engine.

    The RC8D is the same base unit as the BMW D7, indeed from the Hatz range. The gearboxes are different though, as is the charging system I believe. Renault sold off this division, and it became Nanni I think?
    The injector is out, and the cylinder is soaking as I write this. I've had the starter motor out and tried to lever against the ring gear, albeit that was a few days ago. That'll be the 1st attempt on Monday

  29. #29
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    Default Re: Seized Diesel engine.

    I thought the BMW D7 and 12 were based on Farymann blocks? Did Hatz-Farymann have a joint venture?

  30. #30
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    Default Re: Seized Diesel engine.

    I have seen engines seize after just a few days (tractor owner forgot to cover the exhaust and it rained down a vertical stack exhaust) and I have also worked on engines that have not run in 70 years and they turn over by hand just fine.

    Based on the above experience I tend to agree that you have a case of stuck rings, and moreover that you have them because water found it's way into the combustion chamber.

    Once you get her freed up, find out how the water got in, and fix it.

  31. #31
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    Default Re: Seized Diesel engine.

    I am wondering how did you do the cooling system flush? Was the engine in the boat or out of the boat? Was the engine running while you did the flush? Was a hose used to inject water into the engine or was the engine picking up it's fresh water from a bucket (assumes it was running) and using it's water pump to move the water through the system?

  32. #32
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    Default Re: Seized Diesel engine.

    AFAIK, Marvel Mystery Oil is little more than kerosene.
    If you're concerned that acetone will give seals a problem... I'd try ATF + Kerosene ( maybe a little vinegar )

  33. #33
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    Default Re: Seized Diesel engine.

    Many years ago i freed a little 1970 Honda SL100 motor, it was locked solid, rusted shut. Rain through the plug hole.

    I'd stripped it down, the piston was half way down the bore. I filled hole with a mix of diesel and petrol, set the thing on the dirt floor of the workshop and lit the bore on fire. I was 12, I liked playing with gas and petrol. when the flames and smoke had cleared, I used a wood block and whacked it, to my amazement it freed. I honed the bore, buffed the piston, and installed new rings as the originals had come out in pieces... many pieces.. Rode that little bike every Sat Sun for 3 years until I got my licence and a larger bike. The thing is still free and sitting in my workshop in NZ. Been another 25y now since it last ran.
    R
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  34. #34
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by Redeye View Post
    Many years ago i freed a little 1970 Honda SL100 motor, it was locked solid, rusted shut. Rain through the plug hole.

    I'd stripped it down, the piston was half way down the bore. I filled hole with a mix of diesel and petrol, set the thing on the dirt floor of the workshop and lit the bore on fire. I was 12, I liked playing with gas and petrol. when the flames and smoke had cleared, I used a wood block and whacked it, to my amazement it freed. I honed the bore, buffed the piston, and installed new rings as the originals had come out in pieces... many pieces.. Rode that little bike every Sat Sun for 3 years until I got my licence and a larger bike. The thing is still free and sitting in my workshop in NZ. Been another 25y now since it last ran.
    Now that is old school! I love it. I am guessing that you were also the type to seat tires on a rim using a little propane and a match? Now I need to go try this.

  35. #35
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    Default Re: Seized Diesel engine.

    Quote Originally Posted by leop View Post
    I am wondering how did you do the cooling system flush? Was the engine in the boat or out of the boat? Was the engine running while you did the flush? Was a hose used to inject water into the engine or was the engine picking up it's fresh water from a bucket (assumes it was running) and using it's water pump to move the water through the system?
    Apologies for being away from the thread, but 'Varnishing' is my excuse!
    The engine was removed from the boat, and the coolant system was flushed using an inhibitor, I don't recall which one, pouring the liquid into the pump by a tube held above the engine, then drained by rotating the pump.
    I tried to turn the engine yesterday, but no joy. Time's not the enemy yet!

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