Kurrawong_Kid
Well-known member
I believe it is a myth that the MD series were "designed" as marine engines. I understand that the base engine was used in farm generators throughout Scandinavia, just as Listers were in the UK
To scrap or keep an engine, to scrap or keep a boat?!
- Thread starter James W
- Start date
Lakesailor
New member
The engineer seems to know how to talk up a good bill.
Pistons under a microscope. Is this an F1 version of the engine?
It's a solidly built diesel engine. A few scuff marks on the piston crown are hardly a good reason to replace them. If he'd said the bores were oval or the pistons were cracking around the gudgeon pin it would seem worthwhile going for a full rebuild. But if he needs a microscope to detect flaws you want to be asking someone else to appraise it.
jerrytug
N/A
He "had some problems getting in to it" ? WTF? "microscope" are you serious? I have the same motor and it is a bog standard diesel engine, I think your man is on drugs, what's his name so we can have a good laugh?
Sorry about your experience with this character, I beg you to get a second opinion from a NON-MARINE diesel fitter, cheers Jerry.
To the OP, tough decision mate. IMHO I wouldn't spend a penny (take it either way) on a raw water cooled lump.
LeonF
Active member
Thanks for all the input guys. I talked to someone who is a Morris Minor fanatic and knows a bit about engines and he said it's probably because the pistons were seized ? Ok, maybe it is a way to run up a bill, but on the other hand I'd rather have an overzealous engineer than one who takes chances. I'l have a long chat with him before I make any decisions. I am not technically minded so may be misinterpreting him. Your input is just what I was looking for.
Stemar
Well-known member
+1
Isn't there an engine supplier that provides mounts to fit your existing beds? That's one big bill out of the way. (Beta?)
The exhaust's on the wrong side? I can see that being a problem on a car, but a boat exhaust's a lump of (admittedly expensive) rubber tube. You buy it by the metre and it bends. It may be a faff, but not a couple of grand's worth.
I may be doing him an injustice but, from here, it looks like he's either incompetent or taking the piss.
30boat
N/A
Microscopically pitted pistons are probably even better than perfect ones.They'll hold oil better...That's rubbish and just a way of impressing gullible clients.
What will dictate the end of a raw water cooled engine is corrosion and blockage of the water galleries.As long as it 's not too corroded or water circulation is not impaired an engine will keep going.The big ends and main bearings must be within spec of course as well ast the bores rings and valves but all that can be rectified,at a cost,as long as the cooling system is still working.Having said that I believe a new engine would give you peace of mind.
If it were me I would get the engine in my shed ,take it to bits and assess the cost of repairs but I enjoy that kind of thing.It would however be more cost effective to just get a new small engine.
What will dictate the end of a raw water cooled engine is corrosion and blockage of the water galleries.As long as it 's not too corroded or water circulation is not impaired an engine will keep going.The big ends and main bearings must be within spec of course as well ast the bores rings and valves but all that can be rectified,at a cost,as long as the cooling system is still working.Having said that I believe a new engine would give you peace of mind.
If it were me I would get the engine in my shed ,take it to bits and assess the cost of repairs but I enjoy that kind of thing.It would however be more cost effective to just get a new small engine.
LeonF
Active member
30boat I haven't had an in depth chat with him, but could it be that the pitting was just a symptom of water presence rather than a problem in itself ? The injectors were well sooted up, the exhaust water was streaked with grey before it seized. He managed to turn it by hand but it was very stiff, and he said if water had got into the engine the last thing we wanted to do was try and start it. When he got the top end off there was moisture in the piston chambers.
LeonF
Active member
Founds this guys, what do you think of the comments ? http://www.marineengine.com/boat-forum/showthread.php?409708-Piston-Pitting
30boat
N/A
He was right about not starting the engine with those symptoms.There could be water ingression which will emulsify the oil into the grey stuff you got.This can be due to a bad head gasket or a cracked or corroded cylinder liner or casting.These very old engines can finally give up because of corrosion,I once had to rebuild a Buck that had a hole in a liner.In the end it was replaced by a Beta because there were other issues.I replaced my own 22 year old Bukh because there were worrying signs of corrosion on the exhaust manifold and it had been running with the wrong thermostat ( for fresh water cooled engines) for years which made me distrust the whole thing.In the end it's all a matter of willing to risk running an old engine that can break down at any moment,usually the worst one,or investing in a new ,fresh water cooled one that will give oneself peace of mind.I chose the latter.
LeonF
Active member
Mine is fresh water cooled, but a year or so ago I had the raw water bypass the clips on the heat exchanger and enter the freshwater side of things. I only realised when I had water over the floorboards and saw it pouring out of the overflow pipe on the tank cap. My oil was fine, but there were fine marks on the dipstick which he said could be water. He worked on the engine of a friend who had a rope on his prop which shifted the engine, and he insisted on drawing the shaft and checking everything through. My friend has no flies on him and he reckons he is very good.
Lakesailor
New member
Apples and oranges. They suggest that running a cam with large overlaps will cause water ingestion.
Your engine won't have a performance cam in it
That pitting wouldn't require a microscope to identify.
If you do have any water getting in it could cause some pitting, perhaps. Depends how long the motor has been stood with water in it. There would be other problems like water draining to the sump and rings rusting to the cylinder walls.
In your position I would collect the motor and take it to an engineer who refurbs plant.
He may give the same diagnosis. But if the condition needs minute scrutiny to detect, I very much doubt it.
But if you are confident in him, carry on. You did ask.
Your engine won't have a performance cam in it
That pitting wouldn't require a microscope to identify.
If you do have any water getting in it could cause some pitting, perhaps. Depends how long the motor has been stood with water in it. There would be other problems like water draining to the sump and rings rusting to the cylinder walls.
In your position I would collect the motor and take it to an engineer who refurbs plant.
He may give the same diagnosis. But if the condition needs minute scrutiny to detect, I very much doubt it.
But if you are confident in him, carry on. You did ask.
LeonF
Active member
And apologies to James W for hijacking his thread, but I hope all the discussion is helpful.
clyst
Well-known member
Any ingress of water could be from trying repeatedly to start the engine with the sea cock open .
dylanwinter
Active member
30boat
N/A
The waterlock fills up with the repeated cranking and the water not being pushed out by the exhaust pressure fills up the neck and enters the combustion chambers by the exhaust valves.
Kurrawong_Kid
Well-known member
Water in the oil on these engines may be caused by the failure of the water pump seals. Don't ask me how I know!
dylanwinter
Active member
clyst
Well-known member
A few years ago I watch a chap ,funnily enough ina Centaur ,who thought he could motor to the side of the river on the starter motor because of engine failure on leaving its mooring . Hydraulically locked the engine with a resounding bang .
capt_courageous
New member
Glad I have never thought of doing that.
Stemar
Well-known member
It might have worked if he'd closed the water inlet first, but I rather doubt the starter would have enjoyed it. It's one thing to do it in a car to get you off a level crossing, but starters tend to get a bit hot if run for more than a few seconds.
