Engine and sea water

[captlloyd]

Originally Posted by Lepke

Change the oil a couple times and you should be fine. Cruise somewhere so the engine reaches full operating temperature before the oil change.

I agree, it’s worth a shot. Most Diesel engines are tough as nails. Go on YouTube and you can see scores of diesels being started and run after setting for 10, 20, even 30 years. There has to be some rust and condensation in those engines, ( they always drain and refill oil and water).

[Reefmagnet]

Based in large part on the advice given in this thread I'm pulling the motor and will strip it down with the plan to replace all seals and bearings at a minimum. I've also spoken to a very marine deisel savvy friend of mine over a beer today and he tells me I'd be nuts not to fix it up.

So plan is to complete the removal of the gearbox my mechanic couldn't remove (blames corrosion and limited access). I'll run the motor with engine flush and see how that goes then strip it down and give everything a clean up and replace anything that looks damaged or is out of specified limits. I'm actually looking forward to doing this as I always considered this motor to be cursed (crazy sailor, right?) and hopefully this will rid it of that affliction!

[Michael Pope]

I re did an ancient Sabb Norwegian motor weighed over 1000 lbs for 18 Hp but factory claimed 50 year average life in a fish boat.. It had been laying arround and gathering rust so i purchased a small sand blasting setup and found some "Walnut Shell " Blasting powder " took all the rust off with diligence and had no parts to replace except a cracked piston from screwing the decompression lever down too far . Bores miked out to spec and shell washed out easily not like sand, Bought he sander out fit for less that $200.00
A cheap answer, Mike Pope

[Reefmagnet]

Here's what the insides of the engine looks like...

[Wotname]

Well I have see a lot worse!
Pop off a couple of the crankshaft main caps and some big end caps and let us see what the crankshaft journals look like.

[Michael Pope]

Well Reef Magnet is perhaps not familiar with an older style of marine Diesel construction usually referred to as "Line Bored"

The Old Sabb engines and of course many much larger (freighter Sized) engines do not have a Pan as such The entire block and enclosure of the crankshaft are formed in one piece and are not designed to come apart . The journals are "line bored" in the ridgid engine case after assembly. The Sabb engines are made as a front and rear casting and also the crankshaft (in two parts) and are shrink fitted together for evermor one end being at high temperature.
They claim greater long term rigidity and journal life. You access the 'Big ends" thru "doors" on the sides so the engine can stay bolted to its beds in the ship even for a major overhaul . The head and sleeves pistons and rods come out of the top. So my block looked a lot easier to sand blast I only had to blank off where I had removed the intake and exhaust manifold and hang
the engine off a Fork Lift to access the total exterior "Rusty Portion. " only the front and rear seals to protect. The engine was 40 years old but I could not measure the tiny line that showed at the top of the piston ring travel.
The engine the Reef Magnet supplied pictures is a different kettle of fish it looks like a car or truck engine rather that a marine engine. Hard to find an engine designed for marine service these days Mike Pope

[Michael Pope]

I think many older people who remember pre war(WW2) designed Marine engines as heavy quiet fiends that tended not to intrude on your life but served faithfully for 50 years . No electronics . No bloweres just chuff Chuff sometimes at twice your propellor RPM but rarely more . You could set your cup of coffee on the head when running so you could light your pipe with two hands They were friends. The local fishermen with Gasoline engines would leave their Easthopes running when they went up for a beer so they would not have to face starting an engine that hated you as it had had no beer.
When the wooden Troller had a bit of "rain rot" in it and you had a new bigger hull built you overhauled your 5 cylinder Gardner and put it in the new Hull. It did not mind it was a friend! It had heard the fishermen talking "The 5 cylinder always catches more fish --- The six cylinder makes a different noise frightens the Salmon.
I sat and wasted an hour of the manager's Time at Sabb in Norway. Saying why do you not build a new style slow speed diesel for yachts 30 to 50 Hp with different sleeves and pistons to suit . Just very smooth and quiet and do not mind running at 25 degrees heel angle, when they have to, there is a market!! He said you are not the first to tell me that Mr Pope but it takes sailors twenty years to learn that is what they want and another ten for them to buy one. I do not want to be here for thirty years and the Japanese want to buy me out now so they can have all the lifeboat engine market. So Sad!

[Reefmagnet]

Originally Posted by Wotname

Well I have see a lot worse!
Pop off a couple of the crankshaft main caps and some big end caps and let us see what the crankshaft journals look like.

Agree. I'll be pulling the crankshaft out next weekend, but I've removed some caps and a piston in the meantime and scoring is minimal and dimensions are as new. Interesting to note that everything that isn't made of carbon steel, including aluminium components are fine and the things that suffered the most are roller bearings.



The sludge would have killed this engine in short order, though. The rocker arm oil passages, for example, were just about totally clogged with crap which took a fair bit of cleaning to get sorted.

[Reefmagnet]

Originally Posted by Michael Pope

Well Reef Magnet is perhaps not familiar with an older style of marine Diesel construction usually referred to as "Line Bored"

The Old Sabb engines and of course many much larger (freighter Sized) engines do not have a Pan as such The entire block and enclosure of the crankshaft are formed in one piece and are not designed to come apart . The journals are "line bored" in the ridgid engine case after assembly. The Sabb engines are made as a front and rear casting and also the crankshaft (in two parts) and are shrink fitted together for evermor one end being at high temperature.
They claim greater long term rigidity and journal life. You access the 'Big ends" thru "doors" on the sides so the engine can stay bolted to its beds in the ship even for a major overhaul . The head and sleeves pistons and rods come out of the top. So my block looked a lot easier to sand blast I only had to blank off where I had removed the intake and exhaust manifold and hang
the engine off a Fork Lift to access the total exterior "Rusty Portion. " only the front and rear seals to protect. The engine was 40 years old but I could not measure the tiny line that showed at the top of the piston ring travel.
The engine the Reef Magnet supplied pictures is a different kettle of fish it looks like a car or truck engine rather that a marine engine. Hard to find an engine designed for marine service these days Mike Pope

This is only a 30hp motor. I don't think anyone makes a specialty marine engine in small sizes anymore except for maybe Buhk? After my experience, use of more stainless steel instead of carbon steel would be nice

[Wotname]

Originally Posted by Reefmagnet

Agree. I'll be pulling the crankshaft out next weekend, but I've removed some caps and a piston in the meantime and scoring is minimal and dimensions are as new. Interesting to note that everything that isn't made of carbon steel, including aluminium components are fine and the things that suffered the most are roller bearings.



The sludge would have killed this engine in short order, though. The rocker arm oil passages, for example, were just about totally clogged with crap which took a fair bit of cleaning to get sorted.

Sounds like you will only have minimal damage after all. I don't know how you plan to remove the existing rust but considering how mild it looks, I would be inclined to use an electrolysis method like this https://antique-engines.com/electrol.asp but a soda blast would also do IMO.

I have been experimenting with using hydrochloric acid to remove rust (and mill scale) from mild steel and early results are looking good although I don't know how much collateral damage I might be doing so I can't recommend it!

Just for fun, here are a couple of pictures of a more serious sea water/oil incursion . Two before and one after an initial clean up; it's work in progress!

[Reefmagnet]

Originally Posted by Wotname

Sounds like you will only have minimal damage after all. I don't know how you plan to remove the existing rust but considering how mild it looks, I would be inclined to use an electrolysis method like this https://antique-engines.com/electrol.asp but a soda blast would also do IMO.

I have been experimenting with using hydrochloric acid to remove rust (and mill scale) from mild steel and early results are looking good although I don't know how much collateral damage I might be doing so I can't recommend it!

Just for fun, here are a couple of pictures of a more serious sea water/oil incursion . Two before and one after an initial clean up; it's work in progress!

Youch!


Have a look at white vinegar. I researched both vinegar and electrolysis over the weekend and tried the vinegar method and it works great! It takes about the same amount of time to remove rust - it literally just falls off the job after about a 24 hour soak. My cursed engine has been installed using the original mounting brackets because out of all the engines the PO could have chosen to install, the picked the only one too wide to fit the channels in the boat and therefore retained the rusty brackets of indeterminate age. I've got them soaking at the moment in vinegar and will check later how they're going. If that doesn't go to well I've got a bucket ready to go with reobar anodes!

[Wotname]

Originally Posted by Reefmagnet

....... My cursed beloved engine has been installed using the original mounting brackets .........!

There, I fixed it for ya. Bro,ya gotta talk kindly and adoringly to ya engine if ya want it to be there for ya when ya need it, yeah - it's all about engine

The HCl works way faster than the vinegar - unsurprisingly

More seriously, hope your brackets clean up OK!

[Reefmagnet]

Lol.

I have the upmost faith it will be less cursed once shown a bit of loving and attention (in a totally platonic way, of course).

If not, it's next role will be a home for crabs!

[Reefmagnet]

Crankshaft journal...

[Wotname]

Hard to tell from the photo but it isn't severe - might polish out and then measure or if it doesn't, regrind to first undersize; if undersize bearing shells are available.

IMO.