Engine assembly lube - any recommendations?

[Nick Jones]

Interesting........ and strange. Your gauge test method sounds reasonable.

Dont neglect the suction side of the pump. A mate has recently travelled a similar route. Having converted his T25 camper to Subaru power recently, after initially running well it started faltering under prolonged load, then any load, then only able to run at idle.

I lent him a spare pump and a gauge with advice to fit the gauge first. His (new) pump could only manage the expected 2.5 - 3 bar at idle. My (well used) pump was the same or slightly worse. Squeezing the regulator relief line had little effect, showing it was the pump. Seemed unlikely both pumps were faulty so I got him to remove the pre-filter. Problem gone.....

In his case the tank outlet is very small and there may be another strainer in the tank (though not an intact one if the crud in the ore filter is any guide!) so I think he may need to investigate (and invest) further.

Anyway - point is that these roller cell pumps push much better than they pull and suction restrictions matter.  In my view they should only be run with a strainer on the suction side, not a full filter and it should be a big one. 
I’ve used Baldwin BF1173(3/8”) and BF7693 (1/2”) with success

[thebrookster]

As Nick says, your pressure gauge testing method is fine. 

I also agree wholeheartedly with his comments on suction side. Become the bane of my life recently with this new very low sulphur fuel that we have to use onboard, it has me completely amazed by how well it manages to choke a suction strainer! On my fuel pumps onboard a drop of 0.1 bar on the suction side can equate to up to 1.0 bar drop on discharge side! Your pressures will be nowhere as extreme, but be aware a small decrease on suction may have a profound effect!

Phil

[JohnD]

Thanks for that!  Two pro pump experts!

John

[Nick Jones]

2 hours ago, thebrookster said:

On my fuel pumps onboard a drop of 0.1 bar on the suction side can equate to up to 1.0 bar drop on discharge side!

Blimey..... what sort of pump?  Screw pump?  Gear pump?  Any strange noises?  My "main" pump type is progressive cavity.  They suck very well - will pull near full vacuum - but unless chosen very carefully will tend to start to rattle and bang at 6 - 7m lift and be trying get off their baseplates by 8 - 8.5m lift.  Cavitation.......

Seem to recall you have a swirl pot John, and I presume the HP pump draws from that?  Is there any kind of filter/strainer in there or in the suction line to the pump?

[JohnD]

There is a pre-pump filter, and a post pump.  The pre- was recommended and supplied by Prestige, and has a replacable element.    I've inspected it and it's clean as a whistle.    Can't see how that can be obstructing.

The swirl pot (it supples the pre-filter and thne pump)  is an empty container, kept full by a lifter pump, which is a red-top Facet!  The swirl pot top, so hydrostatic pressure to the pump, is about 8 " above the pump.     It all seems fool proof!   And has been!    

Carl wants me to fit the pump in the wheel arch, below the boot, for an added  'assist'.     I know that many TR6s and Pi saloons have it there, but for comopetion I'm reluctant to put it in such a vulnerable position.    maybe instead of raising the Titanic (lowering the pump) I should drain the Atlantic (raise the swirl pot)?

 

[thebrookster]

4 hours ago, Nick Jones said:

Blimey..... what sort of pump?  Screw pump?  Gear pump?  Any strange noises?  My "main" pump type is progressive cavity.  They suck very well - will pull near full vacuum - but unless chosen very carefully will tend to start to rattle and bang at 6 - 7m lift and be trying get off their baseplates by 8 - 8.5m lift.  Cavitation......

Screw type - IMO pumps Nick. Though they are now 14 years old, and taken a fair amount of abuse over those years. Def cavitation, I dread to think what it looks like inside. I am managing by cleaning the strainer on a VERY regular basis, as the powers that be have declared they don't want to overhaul the pump, we shall see how long that lasts.........

[John I]

 

9 hours ago, thebrookster said:

I am managing by cleaning the strainer on a VERY regular basis, as the powers that be have declared they don't want to overhaul the pump, we shall see how long that lasts.........

Ah I see that management have opted for that well known and useful cost saving principle often favoured by ship owners as "failure maintenance"

[Nick Jones]

Hmmmm.  The Chief Engineer should remember the MV Braer........... not strictly the same as due to sea water where it wasn't meant to be, but a reminder that getting fuel to the engines is a mission critical thing!

'Tis true though - have had some dealings with ship supply companies with most of my various employers and they really hate spending money!

Being IMO I imagine they are triple screw pumps, so there will be some wear to the screws as they drive each other directly (as opposed to twin and quad screws that have timing gears, so the screws should never actually touch) and are more sensitive to fine particulates in the pumped medium.  Trouble is, unless they are the cartridge type, if anything more than bearings and seals are needed, overhaul is usually no cheaper than outright replacement.

Is the strainer clogging a general characteristic of low sulphur oil in your experience Phil or is this a mucky batch?  Needs a duplex strainer arrangement with D.P sensors and auto-changeover.......

[thebrookster]

16 minutes ago, Nick Jones said:

Hmmmm.  The Chief Engineer should remember the MV Braer........... not strictly the same as due to sea water where it wasn't meant to be, but a reminder that getting fuel to the engines is a mission critical thing!

'Tis true though - have had some dealings with ship supply companies with most of my various employers and they really hate spending money!

Being IMO I imagine they are triple screw pumps, so there will be some wear to the screws as they drive each other directly (as opposed to twin and quad screws that have timing gears, so the screws should never actually touch) and are more sensitive to fine particulates in the pumped medium.  Trouble is, unless they are the cartridge type, if anything more than bearings and seals are needed, overhaul is usually no cheaper than outright replacement.

24 minutes ago, Nick Jones said:

 

 

Ahhhh, but we monitor everything with vibration analysis which shows the pumps to be fine! The fact we only take the vibration data after filter cleaning is a small detail.

They are triple screw pumps, and given the age I rather suspect the casing is as much at fault as the screws. However, this vessel only has just under 12 months life left with us before going back to owners, so the onus is very much on not spend money!

18 minutes ago, Nick Jones said:

Is the strainer clogging a general characteristic of low sulphur oil in your experience Phil or is this a mucky batch?

Fuel - yeah, seems to be a general characteristic, I suspect down to the refining process. There also seems to be a wild variety in how it comes, sometimes we get what is essentially black diesel, then next batch is much more fuel oil like. But very little warning when the strainer goes, it can be fine one moment, then 10 mins later your standby pumps are suddenly kicking in.

25 minutes ago, Nick Jones said:

Needs a duplex strainer arrangement with D.P sensors and auto-changeover.......

Inline strainers only on fuel systems, we do have duplex on each Diesel Generator (after everything else of course), and Boilers also have them. D.P sensors, nope. We do have auto-changover on the pumps though, via discharge pressure switch.

[JohnD]

Makes my probs with a little Bosch pump pale in significance!

[John I]

Hi Phil, what are you burning.

On the steam ships we used 380cst which was like treacle and needed plenty of heat to even get it near to liquid and that was before the pumps were made to suffer in an effort to move it.

[thebrookster]

17 hours ago, John I said:

Hi Phil, what are you burning.

On the steam ships we used 380cst which was like treacle and needed plenty of heat to even get it near to liquid and that was before the pumps were made to suffer in an effort to move it.

On this ship the fuel is roughly in the region of 180cst, requires heating of between 85 and 125 degrees to reach the required 15cst.

However this ship, and her sister vessel are the only two ships we have burning this VLSFO, all the others have Exhaust Gas Scrubbers and EGR fitted so they are still using HFO380, or MGO when required.

[JohnD]

That this thread has segued (cegyed?) over into a discussion of ship fuel is an example of the universal knowledge available in the Common Room at the Unversity of Sideways!

Thank you guys, I don't feel I know any more, but I feel more educated (an educated man is one who knows where to look up something!)

Edited April 9, 2020 by JohnD

[thebrookster]

2 hours ago, JohnD said:

That this thread has segued (cegyed?) over into a discussion of ship fuel is an example of the universal knowledge available in the Common Room at the Unversity of Sideways!

Thank you guys, I don't feel I know any more, but I feel more educated (an educated man is one who knows where to look up something!)

My apologies for the thread drift John, however does go to show that your problems with the Bosch pump are really not so different to larger scale pumps! Any further fuel comments etc can happily migrate to my tanker thread, as a more suitable location for such topics, leaving this thread clear for any further developments with your pump.

[Nick Jones]

4 hours ago, JohnD said:

an educated man is one who knows where to look up something!

When you reach that magical point of knowing just enough to  realise you know nothing.........  Far too many in this world who never reach that point, but are blissfully unaware.  Arrogance is the enemy of learning.

[JohnD]

OK, it's the gauge, or the sender.

 

Fuel pump returned, tested, and passed AOK, and I'm all set to put it all back together.     But first, let's check the fuel pressure gauge.      Punched out a rubber disk that'll sit in the female connector, and which I can jam the air line up against.     Turn the car on, fuel gauge lights up, air pressure at 80psi    -    and the gauge shows anything up to, Ooooh, 20, and then nothing.    Almost exactly what it did when facing the puel pump.     Could be the gauge, I suppose, but a new sensor is much cheaper.    So ordered one from the US.

Ye gods, what a perfomance!

JOhn

[JohnD]

While I'm waiting for the American Pony Express to haul ass to right outside my door and deliver the new pressure sensor,  I've been reassembling the Turkish Distillery in my boot.     Not to make it look like this:

But like this:

 

I've changed all the hoses to Official Highly Expensive Alcohol Resistant Hosing.     Which needed more than I had before, because this stuff has a softer, thinner(?) wall than the old stuff and kinks more easily on a small radius.  Hence the big loops, that used up more hose than I expected, and made it even more Officially Expensive.

And, digging around in my boxes of bits, I found a box containing a brand new, never used, pressure regulating valve, with integral pressure gauge!   See top left.    Wow!  Where did that come from - I have no memory of ever buying it!    Some fettling by replacing the connectors, so that it fits the old Lucas PRV T-piece, and making a new bracket and new feed tube towards the engine (extra turn for anti-vibration!) and it all goes together.   It sits on the back of the T-piece, and I've braced it ro the tunnel over the axle, as it's a bit heavier than the OE PRV.

However, turning the pumps on (fill the swirl pot, then run the main) and several leaky connections showed themselves.      Run!  Grab the FIA cut-out handle!   Phew!     I gave up while all that spilt fuel evaporated, and made up a spark-proof container for an old pull switch to insert into the electricity supply to the main pump.    Just for once, a victory for my policy of wiring all electrical components with multiway connectors, that just plug together and unplug!   The container is 'spark-proofish', a small cardboard box, sealed all around with duct tape.     Anyway, it means that I can turn on the main pump, and turn it off again, before the boot floods with fuel.  

Several iterations of this, with spannering to re-tighten various joints and the system is fuel tight!     Now, adjust the PRV!    The adjustment screw takes an Allen key, which makes it very easy.    2psi - 20 - 60 - 80 -100 Pounds per square inch!!   We have lift off!     And sure enough, the old sensor on the bulkhead registers - Zero.

What a performance, weeks - months! - of delay, and all because I didn't trust my main pump!  I should have checked the sensor first of all.

I'll able to start on this, before the new front sensor arrives, and once I've bled through to the injectors.  WooHoo!

John

Edited May 3, 2020 by JohnD

[JohnD]

The best-laid schemes o' mice an' men
Gang aft agley,
An' lea'e us nought but grief an' pain,
For promis'd joy!

O, Rabbie, if only you knew!     My Pi continues to give me Pian!

Fuel pump system working again - it probably always was, but the pressure gauge wasn't - and I have 'proper' gauge on the PRV showing upto 120psi (I've not left it there)

So it's on to check that all the injectors work, and stap me vittles, no they don't.    I've made up a rack with a trough where I can test them:

And 1 and 4 don't work at all, 3, 5 &6 do and 2 dribbles.  All the hoses 'pulse' and if I pull on the needle on the non-firing injectors, I get a spray of fuel.  I've replaced each non-firing injector with a 'known-good' spare. without improvement.    So I presume that fuel is getting to them all, just not at sufficient pressure to fire them.    Which seems to be related to the port, not the injector.

Eventually, I inverted each injector.  This would make it spray everywhere, so I confied it in a length of tubing, longer that the spray cone could reach, tapped on the base as I ran the engine (three hands helps here) and Lo!    The laggards started spraying.  It must have been air bubbles in the hoses and injectors.    Compressible air will stop the pressure risng high enough to open the pintles!

But it all took so long that I have to break off and return to it tomorrow.  Fingers crossed!

John

[Nick Jones]

2 hours ago, JohnD said:

It must have been air bubbles in the hoses and injectors.    Compressible air will stop the pressure rising high enough to open the pintles!

Just so. Air (or vapour) is the enemy of PI injectors.  Sometimes even "air up" mid flight.  Same injector tech is used in Bosch K-jet but doesn't suffer the same way as they inject continuously.

Best of luck for tomorrow 

[JohnD]

Indeed, Nick!   In 'Can I get this to work' mode and feeling cautious, I was thinking, Metering unit gummed up, not been used for ages, Did I fit it right?, do I have to send that off for testing now?     So mightily relievd to find a simple solution to a simple problem.

Pi does NOT like air in the lines.   When I first fitted it, it would cut out on every corner, just when you wanted power after the apex, as the pump sucked air due to surge in the tank.   But it would start again shortly after, no doubt as the overrun dragged the angine around and the bubbles through.     It was that quick!  This wasn't!

JOhn