SL3 seized

[Alvin]

Hi Friends,

Have been working on engine within boat (50/70 year old Naval Life Boat 24ft Carval Built) removed heads etc to expose pistons. Fwd most had salt water/aluminium sludge on top. After 4/5 weeks of WD40 on top 5/10mm deep no movement, even with heavy blows on hammer on wood block. End result drilled/chilselled out piston. Could not reach big end to remove, crank was at rear of case. Hoped that with piston out, would be able to turn crank via fwd pulley/sprockets, still solid. The engine was drained early April and found twice as much salt water than oil came out. This week Peter Thompson kindly suggested that removing gearbox may find issue at that interface , he has been so helpful with many issues and manual. Only 30inches underdeck to access, very hard work whatever I do! I wondered if I refitted crank case door and over filled sump with say; Gallon of diesel, two gallons of parafin should equate to salt water level I found originally and leave this for couple of months or less? Might get into problem area, whilst I repair/ paint cabin/hull. Nearest boatyard 5miles to take engine out but want this as last option. My time on boat in the Goldhanger Creek (Essex) is free.

[Denis R]

I guess you discovered this problem after the issue with the exhaust.... Sounds like an engine out job to me. Although I've seen fairly badly seized engines freed up before now, yours does sound like a pretty bad case and I'm not certain that a dunking in paraffin and diesel will help much. Are the other two pistons seized? If so and you can get at the other two rods and detach them you might be able to gain access to the crank by taking the cylinders off? It sounds like it's going to be expensive whatever and a replacement engine might be the better route.....

[HYBRID]

I was once told that brake fluid is quite good a freeing a seized piston, never had to try.

[David]

Hi

Sea water as you proberly already know has terrible effect on cast iron if allowed to dry out from the internal parts, many of our Kelvins have been lost when unwittingly in storage they have dried out, within months the salts react and a concrete like growth takes places which bursts cylinder walls and heads so I suggest whatever you do you do fill it with diesel or oil or any similar and that is full to the brim anywhere that will hold it, this will at least stop you suffering that fate.

It does sound as if removing the engine en-block would be the easiest ultimate course for future working on it, even if you get it freed up it sounds like crankshaft and journals maybe grinding and re-lining, liners or boring will be needed etc etc , the gearbox gears are in possibility just a mass of corroded metal stuck together (I was just looking for a pic I had of a gearbox which had been immersed which looked like one lump of rust inside but cannot locate it, it was however saved when broken down on the bench with new gears etc) much easier "on the bank" to strip it right down and do a job you can be happy will be right.

Best of wishes with the work

david

[Yoda]

I would not try to do anything without removing the whole engine/transmission first. You will just waste your time.

[John Orentas]

Yes I would lift the engine out one way or another.. Saw a good tip for loosening off seized pistons from a bloke who was working on an old aircraft engine..

 

'Hot Oil', heat up a tin cupful of engine oil as hot as you can get it, then pour it into the bores and onto the piston crowns, after 1/2 hour or so it did the trick for him and before long he could get a full rotation on the crank.

[magnetman]

scrap metal value is quite high at the moment apparently

[Alvin]

I guess you discovered this problem after the issue with the exhaust.... Sounds like an engine out job to me. Although I've seen fairly badly seized engines freed up before now, yours does sound like a pretty bad case and I'm not certain that a dunking in paraffin and diesel will help much. Are the other two pistons seized? If so and you can get at the other two rods and detach them you might be able to gain access to the crank by taking the cylinders off? It sounds like it's going to be expensive whatever and a replacement engine might be the better route.....

Thanks Denis,

The other two pistons are free, like the idea. The gear box oil when dipped seemed good and not contaminated. But not sure if there are other routes to flooding parts of engine other than via air intake, which is where it seemed to enter.The gear change seems Ok from fwd/neutral/rev. But not sure how much an indicator this is!

cheers Alvin

[larkshall]

Alvin, I honestly think this is one of thos engines that should be consigned to the scrapyard. Salt water causes terminal damage unless got rid of pronto.

 

Having said that my 1/2 brother and I did manage to dismantle an engine (mercury 100) using 'formula E dismantling fluid' this stuff was used by Trinity House at one time. Even so it took weeks of soking the engine in the stuff in an old oil drum. If I remember correctly the stuff was made by fosmin chemicals...

 

The engine?, had been in 70ft of scilly ilses best salty stuff for 5 weeks