Film On Water From Diesel Exhaust

[MarkSF]

Originally Posted by Brewgyver

Pyrometers is a good idea, but sounds like your engine is still running too cool. That is the biggest factor in fuel carryover. Why the 260 t-stat?
Also avoid running unloaded.

A 260F thermostat? What's he using for coolant, liquid sodium?

[Schooner Chandlery]

Originally Posted by Brewgyver

Pyrometers is a good idea, but sounds like your engine is still running too cool. That is the biggest factor in fuel carryover. Why the 260 t-stat?
Also avoid running unloaded.

I agree that it seems the 160F thermostat would be too low. Ours and most are the 180F (183F to be exact on ours). On gage, the cooling water temperature information is a surrogate for the combustion temperature. If combustion temperature is not high enough "the engine running too cool" there's unburned fuel in the exhaust. A pyrometer is installed for the sole purpose of determining the engine temperature (or individual cylinders if the engine has been set up to accept pyrometers for each one's temp.) It's really the easy way to know for sure that conditions are within range for complete fuel combustion.

[jimbunyard]

Originally Posted by Racer86

At what point is an oily film on the water a violation of EPA rules for no discharge? Just asking,,

Was referring to this. Don't know if it's still valid, I just assume it is...

[Schooner Chandlery]

I believe that it is a rebuttable presumption that boat exhaust is not discharging oil. I would not make problems for myself and other boaters to presume otherwise.

Originally Posted by jimbunyard

Was referring to this. Don't know if it's still valid, I just assume it is...

[paulajayne]

Originally Posted by Schooner Chandlery

I believe that it is a rebuttable presumption that boat exhaust is not discharging oil. I would not make problems for myself and other boaters to presume otherwise.

Diesel is an oil. So any unburnt fuel is an oil discharge. albeit very very small.

[Schooner Chandlery]

Originally Posted by paulajayne

Diesel is an oil. So any unburnt fuel is an oil discharge. albeit very very small.

Your logic means that no diesel powered yachts would EVER be allowed because there is always some portion of fuel unburned. Achieving perfect burn does not happen at all times.

I'll just stick with the rebuttable presumption myself And not be silly enough to rebut it.

[twinboat]

Does this engine have an oil cooler ?

My Volvo Pants TAMD40B has a raw water cooled oil cooler.

If leaking, the oil will pass into the raw water cooling system and out the exhaust.

[captlloyd]

Ever seen a 2cycle run? Smoke and oil all over the place. That is why the big push for outboard 4 strokes. As the exhaust is underwater on 2 stroke outboards, you don't see the amount of pollution going in the water so much. Combustion engines pollute, no getting around that. But new technology has reduced it. A sheen on the water is not rare, two drops of oil will produce a lot. My guess is if you replace that thermostat with a higher temperature, your problem will greatly be reduced.

[wesevans]

check oil cooler and engine compression for blow by. also it might be due to improper air fuel mix resulting in incomplete fuel burn.

[SVTatia]

Originally Posted by Racer86

At what point is an oily film on the water a violation of EPA rules for no discharge? Just asking,,

No it ain't. Oil has no e-coli, so its ok.

[gamayun]

Originally Posted by Racer86

At what point is an oily film on the water a violation of EPA rules for no discharge? Just asking,,

Under EPA permit criteria, "no visual sheen" is the standard, which I think is something like a drop of oil in a gallon of water, but don't quote me on that. Any visual sheen on US waters is a violation of the Clean Water Act. That said, it would be impossible for EPA and Coast Guard to patrol every harbor where someone starts up their boat, but if an enforcement officer is standing next to you while you fill up your fuel tank and you over top it, they may cite you for being careless. They're looking for the big polluters, but our little stuff (and the stuff that washes into the streets every day) equate to many times the Exxon Valdez spill every year.

Every year.

So here's an idea. You could make a little bucket that hooks over the stanchion and is just long enough to catch the first splurge of water from the exhaust. This can then be disposed of in a haz waste facility (ask the marina) or just let the water evaporate in the bucket. It will soon be hot enough in Florida for the latter to happen in no time

[Snowpetrel]

Originally Posted by Schooner Chandlery

You might consider putting an inexpensive pyrometer at the exhaust manifold (as close to the actual manifold as you can do it is way before the water injection point) because then you'll know if your engine is running in the right temperature range. This can tell you a lot about properly loading the engine. We watch the pyrometer temp more than rpm on our engine.


Sent from my iPhone using Cruisers Sailing Forum

Ive used a little infra red heat gun to measure temperatures all over a few different engines. Cheap and easy to use. Might help track down if one cylinder is running cold, or if its the whole system.

[Captain Bob]

I believe that the normal operating temperature fot that engine is+-63 degrees F. Injectors should be rebuilt/recalibrated every 1200 - 1500 hours. Valves should be adjusted every 500 hours (simple fix sometimes). If you are burning excessive amounts of oil, it could be worn oil control rings in the cylinders (big job).

[rwidman]

Folks, If the engine is burning or losing engine oil, it will become apparent because the oil level will drop and oil will have to be added. If the engine is passing unburned diesel fuel, the oil level will not drop.


Consider this when making a diagnosis.

[boatman61]

What colour is your oil..?? if its developing a slight greyish tinge to it, could be the head gasket starting to fail.