burgundyben
Well-Known Member
Hello Paul.
Two questions, what are the long term consequences of low sulphur diesel on my CAV DPA (Diesel Pump A size - you told me, you see, I do listen!)?
Second, where did you get that stripey blazer?
More Bio Diesel D3 scaremongering
- Thread starter DAKA
- Start date
Hello Paul.
Two questions, what are the long term consequences of low sulphur diesel on my CAV DPA (Diesel Pump A size - you told me, you see, I do listen!)?
Second, where did you get that stripey blazer?
Bilgediver
Well-Known Member
DOesn t need to be a sophisticated D3 This also can happen on the geriatric MD2 and later..
It is the diesel in the sump is the problem and quite irrelevant whether Bio or non Bio!!!
The problem is that the diesel carried to the combustion chamber by the oil is igniting and is not under control of the governor. The only way to stop is to close of the air supply at the air inlet. NOT WITH YOUR PALM!!!!
Latestarter1
Well-Known Member
#2 First, moment of weakness in Jermyn Street!
As to your older design DPA it all depends on typically boaty variables.
The first is how 'tired' rotor head is.
Second is engine compartment ventilation and ambient temperature.
As usual a bit of history is useful. Issue with older CAV DPA is based on original design was purchased a zillion years ago from the inventor Vernon D Rooser after he had retired from Stanadyne. Later mechanical governed DPA (70's) was totally different design and a little bit of a crib from the Stanadyne pump of the time. No point in going into the complexities of who came to own what, simple fact is that Delphi came to own CAV and then went bust. In order to climb out of Chapter 11 Delpi did a total slash and burn on support for forty plus year old components and hydraulic governed DPA pump was one. There are literally hundreds of tons of components still in the supply chain, but the tap has been turned off.... Some pump shops do not want to mess with older design DPA, others have absolutely no problem.
The issue is the basic design tolerance of the rotor head and ability to cope with the newer 'lighter' diesel fuels. What you MAY see on days with high ambient temperature with vessels with hot engine compartments is a reluctance to re-start when hot. Heat soak from the engine combined with a tired rotor head which already has slack tolerances by modern standards MAY result in the pump being unable to crack off the injectors. Fixes can be as simple as simply relocating your ‘last chance’ filters off the potentially hot cylinder block to a cooler place.
This is not a matter of people with DPA fuel pumps frantically running around like a one legged man at ass kicking party. Just a matter of knowing the new fuel MAY change their engine operating chacteristics. This is a reliability, not a durability issue and the fuel blenders have some sexy additives which we did not have back last time fuel the fuel changed. I expect people will come up with their snake oil infusions on the mere perception that they may have a problem.
Upside is that you will likely see a reduction in start up smoke
Remember that this is not ultra low sulphur diesel (50ppm) this is virtually sulphur free diesel (10 ppm)
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burgundyben
Well-Known Member
Thanks Paul, to be honest, I only want the Perks to do two more years, enough time to sort the hull out, then I'll drop in a pair of B series.
DAKA
Well-Known Member
You have a very clear understanding of the diesel engine way beyond most of our 4 drawings scribbled on the back of a fag packet 
Bilgediver has really chucked a spanner in the works now though, so my question please latestarter.........
It is now public knowledge that Volvo (cars not penta) have issued a recall on the D5 (road going Volvo penta D3) which includes a sticker advising running on reduced dipstick level, I expect they will have some new dipsticks made in due course.
Now seeing as most of us dont know exactly what we have under our hatches and bonnets , is running on 2/3 dipstick level a sensible precaution or an added hazard, if you owned a D5, engine would you ignore the sticker on the basis that running on low oil is potential more dangerous than a 'stuck throttle' (figure of speech) ?
And more to the point I was intending to run my none volvo boat on 2/3 dipstick level as a precaution, bit like wearing a life jacket, it cant do any harm can it ?
Bilgediver has really chucked a spanner in the works now though, so my question please latestarter.........
It is now public knowledge that Volvo (cars not penta) have issued a recall on the D5 (road going Volvo penta D3) which includes a sticker advising running on reduced dipstick level, I expect they will have some new dipsticks made in due course.
Now seeing as most of us dont know exactly what we have under our hatches and bonnets , is running on 2/3 dipstick level a sensible precaution or an added hazard, if you owned a D5, engine would you ignore the sticker on the basis that running on low oil is potential more dangerous than a 'stuck throttle' (figure of speech) ?
And more to the point I was intending to run my none volvo boat on 2/3 dipstick level as a precaution, bit like wearing a life jacket, it cant do any harm can it ?
PaulGooch
Well-Known Member
Why do you have diesel in the sump ?
How is the sump oil then carrying this diesel to the combustion chamber ?
Sounds to me like your engine is knackered.
PaulGooch
Well-Known Member
Don't see any benefit here. The Volvo (and others) issue has nothing to do with bio fuel and nothing to do with the engines fitted to your boat. It's an issue with some vehicles fitted with particulate filters, which you don't have. The reason they are saying "run at 2/3rd" is to prevent the engine oil levels being too high (normal quantity of oil + some fuel diesel). You don't have a particulate filter, you don't currently get fuel in the oil, so i can't see any gain at all from running the engine on low levels of oil.
Nigelhg
Well-Known Member
Same reason oil goes black- blowpast the rings...same route just the other way.
I have seen diesel engine runaway once on a mercedes engine that has just been serviced (the tech forgot to remove the old oil first and filled it with the 6 litres trhat it took on top of the old oil). The engine reved uncontrolably until it went bang.
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DAKA
Well-Known Member
It is my current understanding that it is entirely due to Bio fuel
I was sort of happy with this until bilgediver chucked his spanner in the works .
If I was explaining to my daughter how an engine worked or taking part in an advanced RYA course then 4 scribbles of an engine on a fag packet would be fine but those days have ended unless you have a ton of iron that produces 30 hp in your boat.
The extra horsepower has come from extra pipes added onto the fag packet , these do create extra routes for diesel and sump oil, theres even one for the exhaust to be introduced back into the pot to create extra torque until the turbo gets up to working pressure.
My post isnt intended to add any arguments, I am attempting to seek extra knowledge.
PaulGooch
Well-Known Member
Really ? How does "blowpast" allow unburned fuel into the sump ?
"Blowpast" is when the pressure caused by the exploding fuel cannot be contained by the rings and escapes into the crank cases, causing crankcase compression. At this point the fuel has already ignited, so no fuel can enter the sump.
If the fuel is getting past the rings on the compression stroke, the rings/bores must be badly worn.
How does this fuel then get passed back into the combustion chamber from the sump ?
PaulGooch
Well-Known Member
Pete, you need to have a re-read. It isn't caused by bio fuel, it's caused by particulate filter systems.
With respect, Bilgedivers post doesn't make any sense to me.
You're talking EGR valves now. An EGR valve will allow exhaust gases back into the inlet tract, but these gases don't allow oil or fuel back into the cylinders. If it did, it would mean there had to be oil or fuel going out of the chimney, if that were the case, sump oil levels would be the least of your worries
EGR valves have been in common use for many years on car engines. They're not there to add zillions of horses, they are part of the emission reduction systems. They can be blanked off on most engines with no noticeable change in performance. (petrol cars will fail MOT emission checks though)
DAKA
Well-Known Member
I think you are reading the May 2010 , you need the Nov 2010 recall.[/QUOTE]
They can be used to increase torque at low revs.
The turbo isnt going to give much pressure at low revs so the pressure can be enhanced with exhaust pressure.
We are getting side tracked.
There must be someone reading this who has had a recall letter.
After Volvo HO agree to issue how long does it take for letters to go out ?
rafiki_
Well-Known Member
This generally happens when the engine is cold, and running rich to ease starting and cold running. The mix is too rich for all the fuel to combust in time, hence unburnt fuel washes down the bore into the sump. This is not really an issue for modern metered engines, but used to happen a lot before clever fuelling systems, which is partly why modern car petrol/diesels will run 20,000 miles between oil change when synthetic oils are used.
ulyden
Well-Known Member
Im afraid im outdated on modern diesel engines. EGR increasing torque? It might be true but I dont think so. Must be that it lowers the max temperature in comb. chamber but this is normaly at maximum torque.
If you do so uoy have to add more oksygen as vell. Then you need more boost and so on.
A diesel burning rich when cold? It depends of how you define rich. My world Lambda <1 . That is black smoke on a diesel.
But i have heard that post injektions are increasing oil consumtion. So that shuld lower the oil level. But this was stated 10years ago by a man from MTU.
If you do so uoy have to add more oksygen as vell. Then you need more boost and so on.
A diesel burning rich when cold? It depends of how you define rich. My world Lambda <1 . That is black smoke on a diesel.
But i have heard that post injektions are increasing oil consumtion. So that shuld lower the oil level. But this was stated 10years ago by a man from MTU.
DAKA
Well-Known Member
a faster EGR valve controller has a significant effect on torque
This report is over 10 years old, the technology has moved on since and is in use .
http://www.mechadyne-int.com/vva-re...esel-engine-with-variable-valve-actuation.pdf
.
ulyden
Well-Known Member
Mabye I stupid but im not reading the article like you do.
They close the EGR valve fast to get more oksygen to combustion. EGR is not helping giving more power or torque. But it might be my englich.
On large engines with high efficiesy turbos you bypass air from compressor direct to turbine inlet to speed up turbo charger. I have tried it. It helps.
They close the EGR valve fast to get more oksygen to combustion. EGR is not helping giving more power or torque. But it might be my englich.
On large engines with high efficiesy turbos you bypass air from compressor direct to turbine inlet to speed up turbo charger. I have tried it. It helps.
DAKA
Well-Known Member
It looked far too long and boring so I didnt read it at all
I just assumed it would back up my current understanding
I'll have a gander this evening and I'll be back
DAKA
Well-Known Member
The phrase EGR wasnt introduced by me on this forum, it has been used loosely for the ease of forum understanding.
I made a statement that exhaust gases can be reintroduced into the intake manifold as a way to boost turbo pressure that is otherwise poor at low revs.
I stand by this and after reading the above report deduce that an increased efficiency of 10% is available by messing with the EGR valve.
The technicalities are irrelevant, the important fact to bear in mind is that pots, sumps, and fuel supply chambers are deliberately opened simultaneously which allows a *theoretical* opportunity for overflowing sump oil to cause runaways. Now the *theoretical* opening isnt really theoretical is it, it does actually exist for a fraction of time, too small to allow much fuel in however these openings happen many thousands of times a minute .
It would appear that diesel used to evaporate as the engine heated but it would appear the Bio diesel doesnt evaporate in the heat and starts to build up increasing in the sump.
On this thread this is a crazy digression and irrelevant to the subject of
overfull sumps from bio diesel causing runaways.
I will close with a simple statement
Anyone with a Volvo D5 reading this may want to check with their main agent to see if a recall affects them.
Anyone else is free to decide if they want to run on Full dipstick , or just off full.
I do not intend to be so keen to keep my oil level at max, my boat rarely needs a topup between changes and I cant see any harm is running on 2/3 dipstick level.
I made a statement that exhaust gases can be reintroduced into the intake manifold as a way to boost turbo pressure that is otherwise poor at low revs.
I stand by this and after reading the above report deduce that an increased efficiency of 10% is available by messing with the EGR valve.
The technicalities are irrelevant, the important fact to bear in mind is that pots, sumps, and fuel supply chambers are deliberately opened simultaneously which allows a *theoretical* opportunity for overflowing sump oil to cause runaways. Now the *theoretical* opening isnt really theoretical is it, it does actually exist for a fraction of time, too small to allow much fuel in however these openings happen many thousands of times a minute .
It would appear that diesel used to evaporate as the engine heated but it would appear the Bio diesel doesnt evaporate in the heat and starts to build up increasing in the sump.
On this thread this is a crazy digression and irrelevant to the subject of
overfull sumps from bio diesel causing runaways.
I will close with a simple statement
Anyone with a Volvo D5 reading this may want to check with their main agent to see if a recall affects them.
Anyone else is free to decide if they want to run on Full dipstick , or just off full.
I do not intend to be so keen to keep my oil level at max, my boat rarely needs a topup between changes and I cant see any harm is running on 2/3 dipstick level.
rafiki_
Well-Known Member
ulyden
Well-Known Member
In racing they are setting the timing exsteme late during gear shift. They also have a bypass valve on compressor (Pop of?) to avoid surge and speed loss on turbo shaft. All this gives bostpressure back much faster.
Elektric turbos are not common. To give a 2 liter engine a bost of 10-15psi you need 8-10hp. that gives lots of amps in your batteri cables. A belt driven compressor is more common. Shaft power on turbos are above 30% of engine power on modern large diesel engines.
Elektric turbos are not common. To give a 2 liter engine a bost of 10-15psi you need 8-10hp. that gives lots of amps in your batteri cables. A belt driven compressor is more common. Shaft power on turbos are above 30% of engine power on modern large diesel engines.