• REMINDER - COVID-19

    Any content, information, or advice found on social media platforms and the wider Internet, including forums such as YBW, should NOT be acted upon unless checked against a reliable, authoritative source, and re-checked, particularly where personal health and liberty is at stake. Seek professional advice/confirmation before acting on such at all times.

    Users who are found to promulgate FAKE NEWS on the forum in regard to this issue, intentional or otherwise, may find their access terminated. It is your responsibility to provide references to bona fide sources.

    FAKE NEWS, in this regard, is that which is posited by organisations, media, etc., that is repeated on the forum, or used to support personal opinion/hypothesis posted by users - FAKE NEWS is not necessarily the personal opinion/hypothesis being posted in itself, any issues with such should be challenged respectfully.

    IN ADDITION it seems that conspiracy theories are finding their way onto the forum. This is not the place for such content. Users who post it may find their access limited or permanently suspended. Please leave it where you find it.

Lack of use engine pic .

Joined
30 Jan 2002
Messages
409
Location
Genoa Italy
Coming back towards Sicily or Sardinia?
Where I'm based (SW Sardinia), we often see boats going/returning to/from Tunisia.
I ca recall also a P115 last summer, in fact - Saint Vincent flagged.
Were you possibly onboard?
We went Villasimius - Bizerte - Bonifacio - Genoa. The P115 would be ex- Mistral 55 I'd imagine.

SW Sardinia i.e. Isola San Pietro area?
 

hinch

Member
Joined
30 Sep 2020
Messages
62
as for fixes if it was my boat and i could get it back to my yard i'd pull and strip and rebuild the engine done it a few times with rusted solid classic engines its a tedious job especially if you end up having to re-sleeve or hone it out to clean the rust up but as a spare time hobby its not too bad. to have that done by someone commercially i'd have thought would be expensive though.
 

MapisM

Well-known member
Joined
11 Mar 2002
Messages
19,451
The P115 would be ex- Mistral 55 I'd imagine.
SW Sardinia i.e. Isola San Pietro area?
Correct, on both counts.
Is also the boat you were referring to a 115, or a 108?
They are the only triple engine Pershings, IIRC.
 

Assassin

Well-known member
Joined
23 Jun 2010
Messages
1,316
Piston and cylinder corrosion is well known on engines in marine environments, or close to the sea.

Generally air enters through the crankcase breather (salt laden) and modern oils are of a much thinner film thickness and are easier for the salt to break through, once oils films are breached you have rapidly advancing rust on all major internal surfaces.

Simple solution: run the engines to temperature and hold at operating temperature for about an hour, the heat evaporates moisture from the engine, boils it off from the oil, and circulating clean oil to the entire engine lubricates it and restores the film thickness.
 

38mess

Well-known member
Joined
9 Apr 2019
Messages
3,112
Location
Wales
Maybe pour some diesel into the bores and leave soak for a few days..
Good luck
 

Jim@sea

Well-known member
Joined
12 Feb 2010
Messages
3,364
Location
Glasson Dock
View attachment 114376
Thought folks might be interested in this awaiting to start boating ?

This is from another group ( Diesel engine maintenance) it’s a pic of a Yanmar 110 Hp that’s been left on the hard in Greece ( I think ) for 1 1/2 years .Heads been removed because the cylinder corrosion has ceased it , it will not turn over even with breaker bar .....and be careful there as excess force could fracture a ring so the guy has not acted like a gorilla.

Plan is pour a 50/50 mix of ATF / diesel about an inch above each piston and leave to soak a few days .

Now with a 4 T engine you would have thought only the cylinders exposed with open valves would get damp air in ?
Both ends the inlet and exhaust?
Buts it’s got all 4 .
I was once told by a mechanic that if you have an engine that is stuck, if you are using a crowbar try to turn the engins rotation backwards first.
 

Portofino

Well-known member
Joined
10 Apr 2011
Messages
9,095
Location
Boat- Western Med
I was once told by a mechanic that if you have an engine that is stuck, if you are using a crowbar try to turn the engins rotation backwards first.
Yes ideally the guys say you want the pistons to go down below there tide marks .
There are few issues here
- Rings are brittle if stuck hence loadsa oil ( various mixtures even edible oils + petrol ) ,Thin oils are obviously better and time is one your side .Not too much force other wise ring fracture .Problem is you May free it up and not notice a ring fracture , how can you ?
Then various abrasives wet n dry ( oil ) various scrubbers + oil to clean off the cylinder walls .Plus wipe / clean / suck out debris .
A lot of guys stress if any metal , excess particles end up under the pistons they will find there way into the bearings and shorten the life .A few reckon water would have seeped under anyhow and advocate a total pull the engine and strip down to access the bottom .
Obviously oil changes when assembled thats a given .
All say send the head away to a rebuilder and accept what’s needed .Valve seats , stems etc thats was popular ( no pic afraid to show you )
Then honing .....essential for diesels .
Some reckon they can remove the rust ( past experience) by hand and not damage it underneath, most suggest it will need re honing .
Then it splits into two re honing camps .Send it away ( thus pulling the engine as stripping ) to a machine shop , others are pretty confident there are manual instruments re honing can be done in situ .

The key board warriors when it’s freed up , suggestions start with “ just buy a new gasket “ and run it!
To “ anchor “ How ever having said that a lot of the pros say it will never be the same again , mention different honing from OEM , rust particles ending up where they do damage despite best hygiene cleaning up .They say they can rebuild it , but prefer a full rebuild inspecting the bottom end , remember the top end too is rebuild by specialists .A lot mention the Labour hrs could rack up if it’s a charge out job .A lot mention they do them but more as a recreational thing kinda buy a wreck and stick it in the corner of the work shop and when quiet do a bit .
The issue of freeing up and getting it going in situ is you are unable to spot a fractured ring ...until it’s running and the blow by ( crank pressure ) increases or leak down test shows leakage , or it runs rough below power .

It could pass a typical buyers sea trail though .....so if a prospective has had a new head gasket alarm bells should be ringing you ought to dig deeper .
 

julians

Well-known member
Joined
11 Jun 2006
Messages
1,682
How does turning the engine over backwards make all pistons go lower than the tide marks? Surely at whatever point the engine stopped some pistons will have been going up, some going down, so if you turn it backwards, then those that were going up will go down (fine), but those that were going down will go up into the tide mark(bad).

Or am I not understanding something?
 

MapisM

Well-known member
Joined
11 Mar 2002
Messages
19,451
How does turning the engine over backwards make all pistons go lower than the tide marks?
Of course you are right, it doesn't.
I'm also very skeptic that the oil can make any difference, because typically any stuck engine has not been run for a lot of time, so the only oil left is in down in the pan.
And by turning it manually with a crowbar you are certainly not moving around any oil.

I suspect that whoever gave Jim@sea that suggestion had another scenario in mind, i.e. a valve stuck open.
In fact, obviously it's not a good idea to insist rotating an engine when a piston is going up against a stuck valve.
Now, how likely it can be that the valve self-unstucks (so to speak) after some camshaft rotation backward, I honestly don't know.
But I guess it doesn't hurt trying.
In the worst case, the piston will hit the valve again on the next rotation, regardless of whether backward or not.
 

Portofino

Well-known member
Joined
10 Apr 2011
Messages
9,095
Location
Boat- Western Med
How does turning the engine over backwards make all pistons go lower than the tide marks? Surely at whatever point the engine stopped some pistons will have been going up, some going down, so if you turn it backwards, then those that were going up will go down (fine), but those that were going down will go up into the tide mark(bad).

Or am I not understanding something?
They were referring to the worst piston #2 .

The “oil “ is concoctions poured on top of the pistons were the water was and left for sufficient time , each guy has own formula .
Needs to be very thin to naturally penetrate with gravity .

This is all the none by the rebuild fix it in situ school btw .

One guy said if it was pulled and the crank removed ( after using his concoction) it was still ceased , users a piece of wood and smacks them down with a sledge hammer .Always budge but with this is total rebuild or at least new rings after clean up .

The water gets into the exhaust manifold and obviously pours into the open valves , but the closed valve cylinders it just sits there and eventually seeps past the closed valves in time , thermal expansion/ contraction over the year .It finds its way down and in .That’s why some arguably are less effected , but all are effected .
One or two questioned “ how come it ends up in all “ Apparently it does .

As i said the steeper than normal ( owner states 30 degree ) ramp , the builders only 10 cm height of the water injection point relative to the WL and sitting valves , and I guess the boat being tipped as its fitted on the trailer with the exhaust outlet ending up maybe deeper than it would have been if it was just docked on a jetty .
It a combination like the middle engine on the P108 a theoretical coming together of everything that influences water siphoning in .
The engine is under the pilot house cabin sole so I assume height is limited re just how much curvature and rise space relative to the WL is available.

Going up a 30 degree wave slope would not matter at 3000 rpm or what ever because of the gas flow .
 

rotrax

Well-known member
Joined
17 Dec 2010
Messages
12,847
Location
South Oxon, Littlehampton and Wellington, NZ.
I had a similar issue, got over getting the engine turning as follows.

I placed two short hanks of 10mm braid in the high cylinders, put the head back on, no pushrods, all valves closed, and tightened the head bolts evenly.

Obviously after a good soak and clean as much as possible.

This gets the two high cylinders moving gently.

The guy who gave me this tip used turned wooden plugs, but I had to use what was around.

Harley Davidson recomend placing a piece of cord down a spark plug hole on the cylinder coming up to closed valves compression stroke to lock it while undoing the crankshaft pinion or drive side crankshaft nut. I thought I might try hanks of braid, it worked perfectly. Braid is soft and non damaging but pretty hard to compress.

I had a bit of braid handy so cut two hanks and taped them so they were higher than the bore. Once it moved I set two at TDC, two at BDC. I ensured ALL holes that led into the oily bits were well sealed and honed the two at BDC, cleaned the honed bores and repeated with the other two.

AFAIK, that engine, a Perkins 4108, is still in regular use on the GU Canal in a Narrowboat.
 

Assassin

Well-known member
Joined
23 Jun 2010
Messages
1,316
The simple solution is to remove the injectors or glowplugs and spray some misting oil into the cylinders, this protects engines with a thick film of oil before storage, and lubricates it after long periods of standing until the engine oil circulates.
 
Top