Just a little insight into the oil side of the VRO2/OMS

[cfauvel]

actually I was thinking the same thing....the rubber check flapper could rip...so the piston would suck oil into the tiny chamber, but as the piston pushes back, it pushes the oil back into the oil-inlet tube.

then the teeny tiny check valve that is the inlet for the oil to be mixed and push up on the pin COULD get clogged by debris....it is VERY small orifice.

so on that, I acquiesce , there could be a few conditions where there would be a no-oil condition.

 

[Bosunsmate]

then the teeny tiny check valve that is the inlet for the oil to be mixed and push up on the pin COULD get clogged by debris....it is VERY small orifice.

Would the pin still activate on this or would the no oil alarm not function properly too?
Look forward to your videos on the pin etc
Off to work now for me
Happy in the knowledge the Americas Cup is now coming down here to New Zealand on thursday

 

[cfauvel]

Would the pin still activate on this or would the no oil alarm not function properly too?
Look forward to your videos on the pin etc
Off to work now for me
Happy in the knowledge the Americas Cup is now coming down here to New Zealand on thursday

the teeny tiny orifice that lets oil into the fuel chamber to be mixed is channeled up to the pin, so if there isn't enough pressure to push that pin up, it won't reset the counter and the system will reach 8192 and sound the alarm.

the oil rushes up the channel on the fuel side, pushes the pin up, then flows around the pin then mixes with the fuel....I'll take a photo of the other side of the fuel mixing area and point out the various parts.

would be cool to fashion a see through port so one could video what is going on inside in realtime.

 

[Fed]

I think a lot of people covert to pre-mix simply because VROs are so expensive then justify it by saying VROs are unreliable.
I should say if I had a VRO1 I'd go premix but with the alarms on later models I'm very comfortable.

Really looking forward to any videos & pictures etc. cfauvel.

 

[cfauvel]

Some more interesting reading from the electrical guru WernerF

http://forums.iboats.com/forum/engi.../552261-vro2-question-about-no-oil-flow-alarm

and to recap a later post by him
http://forums.iboats.com/forum/engi...47-testing-vro-alarm-without-pulling-oil-hose

We need a broken 4 wire OMS to send him so he can inspect the circuit...

 

[cfauvel]

Some more pictures of the Fuel/Oil mix side and the passage ways that let in oil and pushes reset pin.

 

[Bosunsmate]

Good pics, i see what you mean that it is a small oil inlet
If you have a picture of the pistons sometime thatd be great, especially the main one that pressuries the oil chamber

 

[cfauvel]

I can get you a pic of the main piston that draws oil in and then pushes out, but I can't take a photo of the piston that pushes the reset pin....

 

[cfauvel]

Indeed it is an OMS (hence the title) I replaced it over a decade ago...maybe even two....I'll see if can open up MS money to see if I logged the purchase.

Checked my purchase of my current pump it is from 1999, so 18 years old....

 

[cfauvel]

oh yep, i see that. So why would Q7 not be the activator? Otherwise why is it there?

got a reply from the Electrical Engineer....Q7 firing at 128 counts, is what makes the horn sound alternatively on/off and faster depending the speed. Not really understanding how that happens since you'd reach 128 pulses and not get reset.

He also said the type of circuit board they use, 'ceramic', can crack and break the circuit pathways rendering the no-oil alarm useless.

we've pointed out a couple of issues
re: oil delivery
1 - if the check valve for the oil inlet is ruptured it would allow the pressure to push the reset pin (alarm will sound)
2 - the the check valve for the oil to mixture bowl is clogged...thus doesn't push the reset pin (alarm will sound)

re: no-oil alarm
1 - the grey wire to the oil side is cut (alarm will never sound if an actual no-oil condition is present)
2 - the regulator is bad (alarm will never sound if an actual no-oil condition is present)
3 - the circuitry simply goes bad in side the oil side (alarm will never sound if an actual no-oil condition is present)
4 - the horn itself is faulty.

Every oil distribution system has it flaws and potential pitfalls.

 

[cfauvel]

Spoke with the old timer mechanic

"The biggest problems with the VRO2, that I have seen is improper rigging, and poor maintenance. Lots of bits and pieces to this system. The alarm horn was also a problem, it has logic to ID input from 4 sensors. The horns had a high rate of failure, the logic would fail setting in the parts bin. ....... Oil tank almost never serviced, filter would melt on early models, different brands of oil would not mix, the mixed oil would jell and not flow."

 

[Bosunsmate]

Whats your maintenance suggestions? It would be interesting to get hold of one or get someone to dissect one that had failed to see if it fitted with the assumptions above

 

[cfauvel]

Whats your maintenance suggestions?

I would follow the manual's suggestions; at the beginning of the season, check the oil reservoir for water and/or jelling....inspect oil filter and test out low-oil horn

then as per manual test for no-oil circuit...run on pre-mix, disconnect oil line and wait for horn

then as per manual test for oil draw, run on premix and using a clear tube full of oil verify that oil is consumed.

It would be interesting to get hold of one or get someone to dissect one that had failed to see if it fitted with the assumptions above

I've seen the following on youtube.
1 - the air motor diaphragm has rips
2 - the o-ring (small) between the two halves of the air motor is ripped, thus not pumping fuel.
3 - the o-ring and diaphragm on the fuel pump side ripped

4 - fuel leaking from the below pic.



I suspect you could epoxy the seam if it leaking fuel...maybe even super glue would seal it up.

(UPDATE: 07/05/2017 - note i think that if the seal mentioned above is leaking that oil would still be mixed in....
But I will say that if it is leaking fuel there, then on the draw stroke it would suck air, and aerate the fuel/oil mix....that's probably not great)

 

[cfauvel]

refer to following VRO parts blowout

 

[Bosunsmate]

This is a good morning read, ta. It made me think about a couple of questions,
1) Do you think if that spring with the piston that resets the counter fails, that a low pressure oil situation would mean that the alarm does not activate?
Ie the spring isnt pushing down on the piston so the piston is instead activating very easily (Also considering this spring must act with every oil injection is it a replacement item in the service packs?)

2) i cant tell from that diagram but does the oil reset piston have its own chamber or is it pressurised from the mixed fuel area? (What im getting at is would a failure in the outlet of that chamber mean only raw fuel would get to the engine yet the oil pressure chamber would still be pressurised meaning the alarm wouldnt sound however no oil would be making it into the mixing chamber)

 

[cfauvel]

This is a good morning read, ta. It made me think about a couple of questions,
1) Do you think if that spring with the piston that resets the counter fails, that a low pressure oil situation would mean that the alarm does not activate?
Ie the spring isnt pushing down on the piston so the piston is instead activating very easily (Also considering this spring must act with every oil injection is it a replacement item in the service packs?)

the oil reset piston that pushes up the tail end of the reset pin, is not replaceable or serviceable , BUT if the pressure gets too low it won't push up on the tail end of the reset pin,thus NOT resetting the counter and alarm sounds.

2) i cant tell from that diagram but does the oil reset piston have its own chamber or is it pressurised from the mixed fuel area?

it does have it's own chamber, but the cap is sealed at the factory and not serviceable...the piston rises with the pulse of the oil-piston pushing into the oil-chamber

(What im getting at is would a failure in the outlet of that chamber mean only raw fuel would get to the engine yet the oil pressure chamber would still be pressurised meaning the alarm wouldnt sound however no oil would be making it into the mixing chamber)

don't quite follow you, but if anything prevents the reset pin from closing the contacts the horn will sound after 8192 pulses...1365 revs (assuming the tach feed is working)....without the tach feed it isn't going to tell you that there is a bad condition.

 

[cfauvel]

Update:
ok took some videos of some various things...I'll be posting to utube and sharing a link here.

the following was done whilst running on 50:1 premix

1 - With pigtail unplugged - with the oil chamber/electronics off, and a piece of metal to hold in the reset pin took video of engine running so one could see the oil piston going in and out.
(without the oil chamber the piston can travel too far out letting out gas.


2- with pig tail PLUGGED in, oil chamber back on, cover to reset pin OFF, and a foot length of clear vinyl 1/4 ID tube full of oil to the oil inlet, videoed the consumption of the oil with every oil-piston cycle and videoed the reset pin coming down to reset the counter.... hee hee

3 - with the reset pin cover back on and everything back on as it supposed to be, disconnected the oil-inlet tube (clear vinyl tube) and waited for no-oil. After five minuted still no sound....ran jumpers between the two ends of the pig tail and DVA back pin tested the tach voltage and got 10-11v....
By serendipity I climbed into the boat and saw the tach was reading 0 even though the engine was running.....that would explain the no horn for no-oil condition....had a spare regulator and quickly put that in and got a tach reading and better re-charge voltage....but alas it started raining so couldn't test the no-oil condition again


Tomorrow I have to re-do the regulator as it is leaking water around the seal....

 

[cfauvel]

Here is the oil chamber off so one can see the oil piston working.
https://youtu.be/qy4P_u913vE

The vro pumping oil.
https://youtu.be/5MMMHztPvhU

The counter reset pin working
https://youtu.be/gV7zKuVQaD8

 

[Bosunsmate]

Great videos, best trilogy ive watched in a while.
What i was contemplating was if the outlet of the oil chamber where the reset piston is located is blocked then oil wouldnt get to the mixing fuel area and the alarm wouldnt sound as the oil pressure would still be high from the main piston still pressurising the oil chambers.

And what i was wondering about the spring (bear with me) was that when the oil reset piston goes up and hits the counter reset lever then something must be pushing that lever back down so that it can then be hit by the reset piston when it comes back up again, if that thing that does that (which i assume is a spring) failed then it would seem the alarm wouldnt go on as the lever would drop on the electronic end and so be in a constant activated (resetting state). Since you say thats a sealed unit then i guess theres no way that the kits provide a replacement spring for whats under there)

And struth what a conincidence regarding your tach failing. That confirms the no tach no horn theory!

 

[Bosunsmate]

That main piston that pressurises the oil chamber, that is doing its business in the video, do you know if that has rings on it or is it just a snug fit in that bore?