Engine Trials.

[Guest catweazle (Banned Member)]

In this first section we concentrate on exhaust and turbo boost.

lots of indicators of problems how many can you see.

Richard you may need Clives magic glasses.

Turn up the volume in sterio.

[Richard Farrant]

In this first section we concentrate on exhaust and turbo boost.

lots of indicators of problems how many can you see.

Richard you may need Clives magic glasses.

Turn up the volume in sterio.

 

 

 

CW,

 

Port engine sounds a bit down on power. Magic glasses got misted up, will have to play it again :confused:

[Guest catweazle (Banned Member)]

The boost gauge ,only temporary,has reflected light on it but if you look carefully you can see a difference to the starboard one.It may not be down on power,just working harder to make up for the other one,or maybe not.:whistle:

[Richard Farrant]

The boost gauge ,only temporary,has reflected light on it but if you look carefully you can see a difference to the starboard one.It may not be down on power,just working harder to make up for the other one,or maybe not.:whistle:

 

 

I did notice that on the guages. Is this recently, after you repaired the engine?

[Guest catweazle (Banned Member)]

I did notice that on the guages. Is this recently, after you repaired the engine?

This was after the previous disasater,havnt been down for a while,lost interest a bit with the weather etc,allthough the heaters are on its probably warmer than home.Try and get down this wk end and make a start .Watching the vids gets me going again. moorings due end of the month:shocked::shocked:

[N.O.S.]

Well call me a landlubber, but I couldn't make out anything untoward, other than the plastic on the stern ladder must be causing a lot of drag, and the door surround to the engine room looks like it has been in a fire.....:confused:

 

How on earth do you balance the output from a pair of engines? If one is working harder at a given speed, it suggests that either

 

1) the other is running at lower rpm or

 

2) the propeller of the lazier engine is not converting the revs into the same amount of work :cool2:

[Guest catweazle (Banned Member)]

Hi Tony.you must try harder check the exhausts again,Vacum gauges tell a story,the port one is difficult to see but it shows approx i bar more at full throttle.We havnt got a stern ladder.The balance is feel really,its obvious after a while,I kept telling Andy the engineer it wasnt right ,but because it was something you couldnt explain,it just felt flat.The first time we went out and it was fixed and i opened the throttles he knew straight away what i meant,he could feel it,It wasnt a huge difference but enough for 6knts.:-D

One of them is running slower ,but which one.?

Edited January 6, 2009 by catweazle (Banned Member)

[Degsy]

I assume from your comments that you haven't got tachometers but I'm a bit surprised that you couldn't feel it on the wheel, ie having to exert slight pressure to balance the rev difference.

[Guest catweazle (Banned Member)]

We have tachos ,on next clip.The boat did pull one side at the lower rev range.:idea:

[Degsy]

We have tachos ,on next clip.The boat did pull one side at the lower rev range.:idea:

So you know which engine is down and you are just winding us up.:argh:

Richard will be calling round to give you a:n00b:

[Richard Farrant]

Richard will be calling round to give you a :n00b:

 

 

 

:-D :-D :rofl:

[Chrisg]

So you know which engine is down and you are just winding us up.:argh:

Richard will be calling round to give you a:n00b:

 

PW will :n00b::n00b: for us

[Richard Farrant]

PW will :n00b::n00b: for us

 

 

Good thinking Chris, that will save me a journey :tup::

[Guest catweazle (Banned Member)]

So you know which engine is down and you are just winding us up.:argh:

Richard will be calling round to give you a:n00b:

Just testing your observational skills,a lot of time and thought went into trying to solve the problem,and the answer came about by accident.

would you agree there is more smoke from the starboard exhaust.?

[Richard Farrant]

would you agree there is more smoke from the starboard exhaust.?

 

Yes I noticed that, and was that the engine with the damaged piston? Looks like it might have been overfuelling, which was a suggestion re. the piston damage I think :confused:

[Guest catweazle (Banned Member)]

At this stage Richard we are post port engine rebuild,The boat had laid over the winter.It wasnt as bad when we left it.A lot of unburnt fuel in exhaust at the top end.Any attempt to push the port revs up early also made that one smoke.

The governor has an extra fuel device operated by boost pressure,it is adjustable,

lots of fiddling with it just produced more smoke or less power.The governors were swapped pump to pump but that didnt transfer the problem to the port engine.:confused: this starboard engine hadnt given any problems ever,it was however changed early in its life due to a catostrophic failure during race trials,the racks had been ground off to allow extra fuel,fuel timing had been incresed by 6degrees,with an xtra 100 horsepower between the two one went bang.with only 36 hours till the start,Peter thorneycroft robbed an engine from one of the gunboats

they were bldng which used three.:cool2:

[N.O.S.]

But didn't you do the fuel metering tests and found no significant difference? :confused:

 

Surely the engine governor will push fuel in until the speed matches the demand and then find a balance. In which case the only way you get too much smoke (from all cylinders) is if the engine is struggling to make the power output asked of it. So is one cylinder still overfuelling?

 

You have got the normal constant speed governors and nothing fancy?

 

And of course you checked the air filters - DIDN'T YOU CW? :whistle:

[Guest catweazle (Banned Member)]

Fuel metering was set up by CAT when pump was o/hauled,new injectors.

We dont run air cleaners:shocked:

All cyls overfueling,or should we say unable to cope with what there getting.so yes i supose the engine is struggling to make the power asked of it.There is a hydraulic advance and retard unit for timing which is quite complicated,we were at one time suspicious that it may of been that,we swapped them about,these jobs take a long time ,it wasnt that.:argh:

[N.O.S.]

We dont run air cleaners:shocked:

 

 

That's it then, a flying fish stuck in the air intake pipe....

Invoice is in the post.

[Guest catweazle (Banned Member)]

That's it then, a flying fish stuck in the air intake pipe....

Invoice is in the post.

:rofl::rofl::rofl::n00b: Funny enough the shape of a fish and the flow over it

has a lot to do with it.:-D

[N.O.S.]

From www.paxmanhistory.org.uk (see 'regulateurs europa') comes the following:

 

Engine governing is, of course, much more sophisticated than the above introduction may suggest. For instance in a turbocharged diesel the rate at which fuelling is increased during acceleration needs to be controlled. When accelerating there is a time lag between the injection of additional fuel and the turbocharger(s) increasing speed and charge air boost pressure. If too much extra fuel is injected before there is sufficient additional air to ensure its full combustion the results are emission of partially burnt fuel (in the form of smoke), fuel wastage, and potential engine damage. A properly designed governor will limit the rate of increased fuel injection to match the air available for combustion. This is just one example of the various refinements incorporated in modern governors.

 

I've highlighted a bit that I hadn't really appreciated before. Some interesting stuff on this site.

[Degsy]

Rather than being a fuel problem is it an airflow problem causing an incorrect fuel to air ratio which in turn causes overfuelling. A damaged air intake pipe perhaps?

[Degsy]

Hadn't seen NOS's post when I replied.

[N.O.S.]

Hadn't seen NOS's post when I replied.

 

The one about the fish? :cool2:

[Richard Farrant]

I used to go to truck racing when it was in its early days and those with low budgets for tuning were noted as opening to fuel up so much that the engine could become swamped with dense clouds of black smoke. There is an optimum point of fuel quantity or flow and perhaps you are getting too much, have you tried cutting it right back? Something not at all right there somewhere, do you know more than you are telling? I suspect this is another CW guessing game :rofl: