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-   -   Is my engine dead? (https://www.cruisersforum.com/forums/f54/is-my-engine-dead-243814.html)

Carl-T705 29-12-2020 21:04

Re: Is my engine dead?
 
Quote:

Originally Posted by Spider0804 (Post 3296449)
White smoke in exaust is the signifier of head gasket blown.

I have changed a couple head gaskets on vehicles, they are more time consuming than anything to change. You are taking the top half of the motor off.

There should be an owners manual for whatever engine it is with a step by step to take it apart and replace it, keep the engine in time, and put it all back together.

To tell if your piston rings or cylinders are fubar you can grab a compression tester and turn the engine over and compare what you get with the manufacturer spec, compression goes down slightly as hours on a motor pile up in most cases, so it can be a little off.

If thing is starting, not running like crap, and not knocking, the chances are the engine is not fubar though...People do this to cars fairly often and a real good portion of the time the engine can be saved...or they just opt to drive it around forever until it looks like a fog machine.

Good compression, change the head gasket.

A head gasket for a car is 100 bucks or so but marine anything is expensive so probably double.

Worth a try before you drop a buttload of money on an engine.

If you are not mechanically inclined at all and/or do not have a pair of sockets and wrenches you could buy what you need to pull the motor and take it to someone.

At the very least have a mechanic come aboard your boat to test compression and give you an opinion.

. You won't have good compression with a damaged head gasket, sorry.

Carl-T705 29-12-2020 21:08

Re: Is my engine dead?
 
Quote:

Originally Posted by Scubaseas (Post 3296962)
Don't trash the engine for the sake of a head gasket or even a cracked head. Blown head gasket may effect the compression reading. There are a several ways to determine a blown gasket.

If you are not familiar with engine maybe hire a mechanic to diagnose it for you.

One way to diagnose is to put a pressure tester on the coolant reservoir, pump to 14 psi and let sit. Take out injectors or glow plugs. Crank over engine. If coolant/water comes out you have a blown head gasket. Another way is pump up the cooling system , let sit over night then try and hand crank the engine over. Careful as the engine may be hydrolocked. Unlock by removing glow plugs or Injectors then cranking over.

Another way is a leak down test but you will need a compression tester fitting, a leak down tester and compressed air to do this.

Another way is to fill the cooling system and leave the cap off then crank the engine over. If water shoots up into the air you have a head gasket or head issue. This only works on BIG leaks.

Another is to leave the coolant pressure gauge on and run the engine. It will slowly build pressure due to normal thermal expansion but once up to temp it should hold steady. If you warm up the engine and with it running the pressure continually builds up then yes, you have a blown gasket or warped or cracked head. This is a good way to check for small leaks.

If you have a blown head gasket you should start to see the engine oil start to look like a chocolate milkshake. This may take a couple of hours or even longer to happen.

Rule out salt water smoke by running the engine without the raw water going to it for about 2 to 3 minutes when the engine is cold. If the smoke stops you have a problem where raw water is getting into the engine somewhere. Possibly at the mixing elbow. Watch the exhaust hose doesn't get too hot when doing this but you can run the engine for short periods without raw water going to it.

Possible you de-tempered the piston rings but I kinda doubt it. You would need to get the head off to tell you if then fixing the boat is worth it or not by looking at and measuring the bores.

NCBoatrx has a good plan. Ditto pete7 Look at Youtube "Bums on a boat" who just took their head off of a MD2030 which is the same beast. It's really not hard to do.

Does the smoke smell like oil and leave a sheen on the water? Or does it smell like steam from a kettle? Or smell like diesel and also leave a sheen on the water?

. You don't have to remove anything to remove water from a cylinder, simply turn the engine over in the reverse rotation and the water will be pump out the exhaust valve.

Carl-T705 29-12-2020 21:19

Re: Is my engine dead?
 
If you ran the engine long enough without coolant to seize the engine you did damage to it. I doubt it's a damaged head gasket. The piston got hot enough to seize in the bore, that's what locked the engine . If your engine has any fore and aft angle to it, the bore at the highest elevation is the one that locked the engine down. My guess is the piston rings are welded to the piston or simply the rings are broken. The continued running of the engine is destroying the bore and the block will need an oversized bore and new pistons and rings. Be prepared to spend some serious money.

vic008 29-12-2020 21:29

Re: Is my engine dead?
 
Complete gasket/seal set about $us110 plus freight

Ballsnall 01-01-2021 16:09

Re: Is my engine dead?
 
Quote:

Originally Posted by Goofeyfoot (Post 3296398)
Is my engine dead?

So I guess the question is, given that the boat overheated, that a gasket blew, am I now foolish to continue to repair the engine? Should I chuck the engine? Should I fix it? Whatís the likelihood that it will ever be right?

Engines get repaired all the time and if done correctly there is no reason it will not go on to achieve full service life.

"Should I chuck the engine? Should I fix it? "

To answer this you will need to work out if it is economical to repair. It's a 20 year old engine, so you need to balance up the current hrs v expected hrs.
What will be the cost of repair, first you need an accurate diagnosis and you won't get that on a forum. Have a professional diagnosis done and repair quoted.
Get quotes for a new engine and also for full rebuild of current engine. Now you have a starting point to analyse your options. Add any other external considerations, ie: maybe the boat is underpowered and this is a good opportunity to upgrade, or your planning a circumnavigation and a new engine is appealing.

On the face of it I would agree you either have a blown head gasket or a cracked head. So factor in that you will need to remove the head to find out which it is and this will need to be done before you can make an informed decision either way. It's quite possible and probable that you have scoring of the piston & cylinders as well.
Hope that helps.

vic008 01-01-2021 19:14

Re: Is my engine dead?
 
Fully endorse Ballsall.Head off then get mechanic to inspect all.
Keep us informed please

Scubaseas 01-01-2021 19:47

Re: Is my engine dead?
 
Quote:

Originally Posted by Carl-T705 (Post 3309375)
If you ran the engine long enough without coolant to seize the engine you did damage to it. I doubt it's a damaged head gasket. The piston got hot enough to seize in the bore, that's what locked the engine . If your engine has any fore and aft angle to it, the bore at the highest elevation is the one that locked the engine down. My guess is the piston rings are welded to the piston or simply the rings are broken. The continued running of the engine is destroying the bore and the block will need an oversized bore and new pistons and rings. Be prepared to spend some serious money.

Indeed but the OP never said motor seized. His complaint is "However, now the engine belches white smoke all the time. It doesnít go away after you run the boat for awhile. So Iím thinking that something happened in the overheat situation, maybe a head gasket or something blew. I really donít know much about these things."

Leak down test could give you more information. Smoke is either coolant, oil or fuel. Really need more info to tell, like does it use coolant, does it overheat still, does the smoke smell like diesel or rotten apples, or like salty steam.

Scubaseas 01-01-2021 19:52

Re: Is my engine dead?
 
Quote:

Originally Posted by Carl-T705 (Post 3309373)
. You don't have to remove anything to remove water from a cylinder, simply turn the engine over in the reverse rotation and the water will be pump out the exhaust valve.

Absolutely correct but I said "One way to diagnose is to put a pressure tester on the coolant reservoir, pump to 14 psi and let sit. Take out injectors or glow plugs. Crank over engine. If coolant/water comes out you have a blown head gasket. " which would tell you what cylinder had fluid in it.

Ballsnall 01-01-2021 20:24

Re: Is my engine dead?
 
Quote:

Originally Posted by Goofeyfoot (Post 3296398)
Is my engine dead?

The engine stopped dead ss a result.

I'd call that a seized engine Scubaseas. So highly probable piston & bores are scored. Do the cylinder compression test, coolant checks, oil analysis etc, then pull the head.
Maybe lucky and get away with a head gasket & cyl hone, but you just don't know till the head comes off.

Scubaseas 01-01-2021 20:46

Re: Is my engine dead?
 
Quote:

Originally Posted by Ballsnall (Post 3311456)
I'd call that a seized engine Scubaseas. So highly probable piston & bores are scored. Do the cylinder compression test, coolant checks, oil analysis etc, then pull the head.
Maybe lucky and get away with a head gasket & cyl hone, but you just don't know till the head comes off.

Missed that sorry but usually the motor will do a lot of knocking before it gets to the point of the pistons seizing in the bores. Ring tension may be shot at that kind of heat.

I agree taking the head off would be wise.

Ballsnall 01-01-2021 22:13

Re: Is my engine dead?
 
With overheating the engine sezure can happen quite suddenly if the engine is only at idle and the damage may be very minimal, if it happened under load or high speed then pretty much can guarantee some sort of damage.


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