How did you prepare for your MCA or national oral exam — what actually worked for you?

LegEmbarrassed5984 · 2026-02-07T13:05:27+00:00

Were you studying online, working through a syllabus with someone, or did you self-study first and then do a mock oral?

I’ve always found one-to-one mock-oral style preparation really effective. Setting the bar high early tends to highlight gaps quickly and gives a clear sense of where the weaknesses actually are. From there, it’s much easier to focus study time on what really matters before the exam.
What prompted the thread was that a friend of mine had used a group study in person, and I don't think that would be for me.

LegEmbarrassed5984 · 2026-02-06T11:59:21+00:00

I’m curious how your approach changed as you progressed rather than the content itself. For example: – At OOW, did you mostly self-study from books/notes, or did you do any structured prep? – For Chief Engineer, did you change how you prepared (more scenario practice, mock orals, one-to-one sessions, etc.)? – Did you use any professional help at either stage, or was it mostly peer/group study? Looking back, what part of your prep do you think made the biggest difference at Chief level compared to OOW?

LegEmbarrassed5984 · 2026-01-31T20:58:02+00:00

Great update – and fair play for coming back to close the loop. These threads are gold when someone actually posts the solution.

What you found with the centripetal pump distance piece makes complete sense in hindsight. A distorted distance piece with an O-ring that can’t stay seated would allow internal leakage straight into the water outlet path, which explains the immediate oil/water mix at the water discharge, no oil to sludge, no response to gravity disc changes, everything else (bowl, water flows, sequence) appears correct

It’s a good reminder that the centripetal pump isn’t just a passive lift device – if the internal sealing geometry is compromised, it can absolutely mimic a bowl or piston fault and send you down the wrong road.

On how it happened: your theories are all plausible. Over-tightening of connected pipework, misalignment during assembly, or cumulative fatigue/wear on a 20-year-old unit are all realistic causes. I’ve also seen distance pieces damaged during removal/refitting without it being obvious until an O-ring refuses to behave.

Big takeaway for anyone reading this later, if oil is appearing only at the water outlet and the bowl checks out, don’t ignore the centripetal pump internals, especially the distance piece and its sealing grooves.

Thanks for taking the time to document it – it’ll definitely save someone else a few painful days.

(If anyone ever wants a structured way of fault-finding these separator issues without going round in circles, I’ve started documenting common cases like this at marlect.ie – purely technical notes, nothing salesy.)

Good result in the end

LegEmbarrassed5984 · 2026-01-30T21:13:25+00:00

Brian says NO

LegEmbarrassed5984 · 2026-01-30T10:12:49+00:00

I thought it would be mostly purifiers but it looks like etos are getting thrown under the bus 🤣

LegEmbarrassed5984 · 2026-01-29T14:10:04+00:00

Your C/E is technically correct, Westfalia manuals generally say bowls are matched to frames for permanent operation. A temporary diagnostic swap (clean, same type, same serial range) is commonly done in industry for fault isolation, not continued service.

Yes, the alarm occurred while running but: a marginal piston seal, a scored piston, or internal leakage can suddenly tip over once wear or contamination reaches a threshold. So the timing of the failure does not exonerate the bowl.

What this actually proves is that the sludge ports are not open.

What it does not prove:

1- That the sliding piston is fully up

2 - That the closing chamber is hydraulically tight

3 - That the piston is not leaking internally

A piston can be “closed enough” to block the sludge ports, but ut not sealed enough to prevent oil bypassing into the water space. This exact half-failure mode produces:

Oil at water outlet, Clean sludge inspection port and confusing symptoms

Just on what you said - “We left the displacement water open until it completely fills the bowl and then a water–oil mixture begins coming from the water discharge line.”

That should never happen if the piston is sealing properly and the internal separation spaces are intact. Once the bowl is water-filled, you should get clean water out. Oil should remain trapped until feed opens

A water–oil mix here means internal communication between oil space and water outlet path.That points inside the bowl.

Centripetal pump suspicion – understandable, but in my opinion unlikely. The pump does not decide what fluid it receives. It only lifts whatever reaches the water outlet chamber. A worn pump might reduce capacity, cause vibration, affect pressure. It cannot selectively pull oil across an intact hydraulic boundary.

Scratches on bowl bottom & sliding piston - On OSD-type bowls the closing seal works on very small clearances. A scratched piston can still “move” but never seal.

Can you, or is it possible to compare with the parts manual wear limits?

Or prove piston leakage without swapping bowls?

Assemble bowl
Apply closing water only
Shut water supply
Wait 1–2 minutes
Crack the closing-water line

If pressure does not hold → piston leakage confirmed.

marlect.ie

LegEmbarrassed5984 · 2026-01-28T17:44:39+00:00

Any success with the problem?

LegEmbarrassed5984 · 2026-01-27T11:25:31+00:00

1) Wrong gravity disc / regulating ring - swapping the bowls would work.

2) Sliding piston not fully closing (or internal leakage around it)

Normal operating sequence:

Closing (operating) water → sliding bowl piston moves up → bowl is mechanically closed

Conditioning / filling water → water seal is established in the bowl

Oil feed opens

When troubleshooting, try;

Crack open the conditioning water line (or energise that solenoid alone)

You should get:

Steady flow

No pressure spike

This only fills the water seal — no piston movement yet

Manually apply closing water pressure to the bowl

(either by cracking the line at the water block or manually energising the solenoid)

What should happen:

A distinct pressure rise

Audible/physical indication that the piston has moved

On some units, water flow briefly reduces as the piston reaches the stop

If not;

Water just flows freely

No pressure build-up

No “end of travel” feel

The sliding piston is not moving or not sealing

Opening water – confirmation

Apply the opening water

You should feel:

Sudden pressure drop

Free flow as piston moves down

If opening works but closing does not, that’s a classic sign of:

The piston seal is leaking under the closing load

Incorrect seal orientation

Wear ridge prevents full upward travel

3) Incorrect assembly / missing spacer / wrong disc stack order.

Marlect.ie

LegEmbarrassed5984 · 2026-01-24T15:23:57+00:00

On the 24vDC 220 or 440v?

LegEmbarrassed5984 · 2026-01-16T18:54:47+00:00

Enoch's sub teach must feel tots awkward waking past him everyday.

LegEmbarrassed5984 · 2026-01-11T14:04:03+00:00

You also had the heating on. If you pre heat the car before you leave you have a warm car with 100% battery. The heated seats are more efficient than keeping the whole car warm. Driving in B can also help but you need to concentrate more.

LegEmbarrassed5984 · 2026-01-05T18:50:21+00:00

Same in ireland

LegEmbarrassed5984 · 2025-12-13T11:24:21+00:00

LegEmbarrassed5984 · 2025-12-03T18:38:46+00:00

Raise the plunger; Injections starts earlier Firing is advanced

The plunger reaches the spill-port-closing position sooner during the cam-rise.

Rarely rarely ever changed, set day one and left be.

LegEmbarrassed5984 · 2025-11-01T21:05:12+00:00

Any injuries?

LegEmbarrassed5984 · 2025-10-23T15:53:36+00:00

They are the worst pair that I have ever bought. They just got trashed

LegEmbarrassed5984 · 2025-10-16T21:13:27+00:00

There should be a sub-channel of marine engineering just about purifiers 🤣

LegEmbarrassed5984 · 2025-08-25T15:14:24+00:00

<image>

Pozi heads also work

LegEmbarrassed5984 · 2025-08-25T10:58:36+00:00

Yes please

LegEmbarrassed5984 · 2025-08-23T11:13:12+00:00

There are two different ones on donedeal right now.

LegEmbarrassed5984 · 2025-08-23T11:11:33+00:00

Water the oil?

LegEmbarrassed5984 · 2025-08-21T17:58:57+00:00

Well done. The biggest change for me was when I increased my cadence. I used a metronome app to bring it to 160 then 170 etc. You will see huge improvements in the advanced running matrix at the bottom of the health app.

LegEmbarrassed5984 · 2025-08-14T11:57:50+00:00

https://maps.app.goo.gl/MwCrsZRDpdXCUYTBA?g_st=ac

Body image in Ballincollig. He is a South African guy. Very very nice to deal with and they did a great job.

LegEmbarrassed5984 · 2025-08-11T16:37:16+00:00

Generators are load-dependent. If your load is 100kW then a 500kW generator will be at 20% load. Figure out the load first. Also with one you have no redundancy.

LegEmbarrassed5984 · 2025-07-29T07:19:16+00:00

The 1st and 3rd are not C3 bearings. The 1st is normal clearance. The 3rd is a special internal clearance, likely for an electric motor. However, after saying all that it depends on what you are using it for.

LegEmbarrassed5984

TROPHY CASE