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-   -   How to destroy a diesel in one easy step... (http://www.sailnet.com/forums/diesel/84596-how-destroy-diesel-one-easy-step.html)

MedSailor 03-04-2012 12:43 PM

How to destroy a diesel in one easy step...
 
The experience of last weekend, where I thought I had sucked water back from my exhaust into my cylinders scared the $hit out of me. I don't fear too many things on my boat anymore, but $$$uddenly ruining my diesel for good is one of them.

So how can one destroy a perfectly good diesel? Lets get a list going. Let's also get a parallel list of how to prevent destruction.:D Of course proper maintenance, inspections, etc is assumed. This list is meant to be of the sudden causes of premature death.


Ways to ruin your diesel:

1. Loosing oil pressure.
--Prevent by installing a gauge and audible alarm.

2. Overheating.
--Prevent by installing a gauge and audible alarm.

3. Filling your exhaust circuit with water while cranking when cold starting.
--Modify starting system and engine to improve cold starting. Crank with raw water closed. Install raw water diverter for use when cranking for long periods.

MedSailor

bljones 03-04-2012 01:03 PM

FORGETTING to open your raw water intake AFTER you have started the engine.

Not changing the oil regularly, Not changing oil filter. Forgetting to refill crankcase with oil after emptying crankcase and changing filter.

Not winterizing. Not rewinterizing.

Neglecting seacocks.

Faster 03-04-2012 01:04 PM

4. Don't be vigilant about inspecting belts and replacing them ahead of failure. ESP timing belts. Few diesels are clearance engines, meaning the pistons won't clear an open valve at TDC.. so if the cam stops and the crank doesn't, WHAM - 2200 rpm to zero in a heartbeat or less.

... don't ask how I know.... If you're lucky you'll just need a head rebuild.. but pistons may be damaged too.

In our case the belt was not old, but a nut vibrated off a belt guide fitting and fell into the crank sprocket, tried to go around under the belt and - SNAP - WHAM - STOP - silence.....

We were three days from home and limped back, sailing when we could and hip-towing our 40' 16,000lb boat with our trusty 5 hp Nissan on our inflatable when we couldn't.

erps 03-04-2012 01:13 PM

put off dealing with a worn cutlass bearing, which leads to excessive engine vibration, which leads to a ten pound alternator shaking back and forth, which leads to the timing chain cover breaking open where the alternator bolts on.

Faster 03-04-2012 02:04 PM

Quote:

Originally Posted by erps (Post 840072)
put off dealing with a worn cutlass bearing, which leads to excessive engine vibration, which leads to a ten pound alternator shaking back and forth, which leads to the timing chain cover breaking open where the alternator bolts on.

... and you know this how????;);):)

Capt Len 03-04-2012 08:33 PM

I've had considerable success over the years in keeping things in safe and top condition but releasing the pull stop prematurely caused my 100 hp diesel to do the back stroke with water from the wet exhaust. Shook the boat but only bent 3 of the 4 con rods.After I did complete re and re for 8 grand I'm much more careful and the bruises on my butt have faded somewhat.As an aside I put a solenoid valve on the riser to drain if the anti syphon were to fail (oil press) Works and I think it's a good idea.

davidpm 03-04-2012 08:41 PM

Re: How to destroy a diesel in one easy step...
 
Quote:

Originally Posted by Capt Len (Post 840215)
I've had considerable success over the years in keeping things in safe and top condition but releasing the pull stop prematurely caused my 100 hp diesel to do the back stroke with water from the wet exhaust. Shook the boat but only bent 3 of the 4 con rods.After I did complete re and re for 8 grand I'm much more careful and the bruises on my butt have faded somewhat.As an aside I put a solenoid valve on the riser to drain if the anti syphon were to fail (oil press) Works and I think it's a good idea.

I didn't follow that exactly.
What did you do?

Capt Len 03-04-2012 09:07 PM

Re: How to destroy a diesel in one easy step...
 
Are you asking about bending the engine or draining the water lift muffler??

jrd22 03-04-2012 09:07 PM

Re: How to destroy a diesel in one easy step...
 
Overheating has got to be one of the most common ways a marine engine bites the dust. Lack of maintenance is probably the main culprit. Impellers, hoses, hose clamps, water pump belts and circulating pumps can all fail and it doesn't take very long to cause damage if at high rpm. Mostly a matter of maintenance to prevent failures and just using the good old eyeball on a regular basis to look things over. The alarms that warn of a lack of raw water seem like a good idea, although I haven't installed one yet.

tomperanteau 03-04-2012 09:31 PM

Re: How to destroy a diesel in one easy step...
 
I have a good one. Our diesel was just reinstalled three days ago after a topside rebuild.

You have to calculate exactly how long your water pump belt will last, wait until about a minute before it breaks. Have someone bump the key off (alarms go off), then wait until you smell paint burning. There you have it - a blown head gasket on a new Yanmar with 140 hours on it!

Then $2200 later your new Yanmar 30 is back up and running.


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