low hours/low oil pressure

[motthediesel]

I'm new here, but I've owned Kubota equipment for quite a few years. My current problem is not with one of my tractors, but with the Beta/Kubota engine in my boat. The boat is an older mini-trawler, an Albin 27. I recently replaced the original Lehman/Peugeot engine with a 50 hp Kubota-based engine removed from a lifeboat.

The engine had less than 10 hrs on the clock when I got it, and has about 20 on it now. It runs great, it starts instantly, runs smooth, and has no worrying mechanical noises. The problem is that while it shows about 50 psi oil pressure cold, that drops down to about 15 psi when at operating temperature.

This is a V2203 engine (coincidentally, the same as in my L4310) and I've done a good bit of research -- I'm wondering if this could be the camshaft plug issue, or perhaps the relief valve? I would really appreciate any ideas I could get from this forum.

I can't work on the front of the engine as it is in the boat, but I can use my home-built gantry to hoist it up into the cockpit to give me access. I'd just like to have a little better idea of what I'm looking for though before I dive in to that step.

Thanks in advance,

Tom

 

[MapleLeafFarmer]

The problem is that while it shows about 50 psi oil pressure cold, that drops down to about 15 psi when at operating temperature.

Thanks in advance,

Tom

At what rpm are you seeing the 15psi

Maybe test the oil sending unit first?

 

[motthediesel]

At what rpm are you seeing the 15psi

Maybe test the oil sending unit first?

That’s 15psi at cruising speed, about 1900 rpm, it drops to 10 or so at idle.

I went all through the sender/gauge thing last year — those readings are pretty accurate I’m sure.

 

[GeoHorn]

WHY was it “removed from a lifeboat”..?

 

[motthediesel]

WHY was it “removed from a lifeboat”..?

The ship the lifeboat was on was torn down/wrecked in India, so all associated equipment is then typically sold off by the wreckers. As for buying it, and having it shipped to the US, that's a story for another time.

I have family in the maritime trades, and I'm told that lifeboat engines are, as a matter of regulation, run every month by the 3rd mate, with the test logged. They are only run for 5 mins or so, accounting for the low total hours seen. Operated like that, of course, the the low pressure at operating temps problem I see now would never even show up.

 

[GeoHorn]

I’m not meaning to cast dispersion on your choice to re-dedicate this engine… But I would surmise that an engine which is started only once-a-month and run for only 5 mins…. is undergoing the Highest Wear periods an engine can suffer…. and doing so repeatedly month after month … might not have the service-history we’d prefer.

Low operating hours are much less important than how those hours were spent, IMO.

Low oil pressure at warm operating temps are indicative of worn main bearings (excessive clearances)…. which is common for bearings which were abused with frequent starting and lack of proper warm-up. We’ve all know the warm-up of our engines is the high-wear part of their lives.

You might make some attempts to drop the sump, pull main caps, and check with plasti-gage for excessive clearances.

On the bright-side… only ten psi of pressure is actually required to allow an engine to operate well. It’s an imagined farce that higher oil pressures are better than lower… All that is necessary is that each wear-surface receive a good supply….and ten psi is likely just fine. (provided that each area gets that 10 psi….and it’s not being sensed Only at the sending-unit….and dumped prior to reaching the mains, rods, wrists, cams, lifters, etc. THAT determination will likely show up fairly soon however with evidence in the filters and noise.)

 

[TheOldHokie]

I know nothing about marine engines.

But engine oil pressure has nothing to do with oil film thickness inside the main and rod bearings. You just need enough to keep them supplied with makeup oil. Journal bearings will work perfectly at "zero" oil pressure.

Engine oil pressure plays a much larger role in keeping spray lunricated parts like cylinder walls lubricated. The pressure and volumes needed varies greatly by design and application.

Before I would want to speculate on bearing wear on a engine with those hours I would want to know what new oil pressure was. Has there been any drop in the last 10? If not you may be looking at perfectly normal pressure. Keep an eye on it. If theres a problem you will see it start to fall off.

Dan

 

[D2Cat]

When Caterpillar first came out with the small D2's they were marketed to farmers who were use to gasoline powered tractors. Selling points were less compaction and able to work fields earlier.

One problem Cat received was farmers reporting low oil pressure. Many farmers insisted there was engine problems just waiting to happen, and insisted on updating, fixing, or finding a solution of some kind.

The solution was a change in the oil pressure gauge! They took the numbers off the gauge and used colors to indicate proper oil pressure. This is an aftermarket gauge, but this was the solution. Cat had used a low pressure, high volume pump to facilitate engine lubrication when at different operating angles.

I'd be sure what the specs were when new before too much concern.

 

[North Idaho Wolfman]

It's not very likely any cam plug or such, these engines changed the way they do it.

There are several different variations of the V2203, and each one is different.
Get me a picture of the top of the engine and the oil filter area.

Was the original oil pan and pick up used?

 

[#40Fan]

An oil sample would tell you a lot about the engine.

Being it came from India, I can only think of it being pulled out of a boat at some point and rebuilt on the ground near some disgusting waterway. Then sold to you as a low hour engine.

I guess I watch too much YouTube.

 

[GeoHorn]

I like what Dan posted…but will add that “spray” on cylinder walls are usually adequate from “sling” off the crankshaft and big-end of the conn-rod….as long as the engine isn’t forced to “idle” at very low speeds for long periods.

 

[motthediesel]

Well, I don't see anything on this engine to make me think it was ever opened up. The paint on all the boltheads and nuts is undisturbed. And as for the cold start issue, sure this thing was probably given 12 cold starts a year for 15 to 20 years, so maybe 240 total? In regular use, a tractor would always get one cold start a day, so you could easily get that many in one year -- I don't think that's the problem.

Was the original oil pan and pick up used?

I believe the oil pan is specific to the marine (Beta Marine UK) conversion.

Here's an image of the engine tag on the valve cover if that helps:





I have tried several different electrical oil pressure gauges, and I also tried different senders. I also plumbed in a manual gauge, and the results are always just about the same. I get that oil pressure beyond a certain point is not really needed, but I just get the willies when I look at that gauge, I can't help myself.

I have ordered the parts and gaskets I need to take off the front timing case and take a look at things in there. I want to check the relief valve, and to see with my own eyes that there are no obvious plugs missing. That's a big job, because in the engine room, there's very little access to the front of the motor. I'll have to set up my little gantry, pull in out and set it up on blocks in the cockpit. Not a job I relish, but I just can't enjoy the boat as is.

 

[Firefight100]

So to be accurate, here are the pressure specs for a 2203. For the Kubota V2203 diesel engine, the factory oil pressure specification is 7 psi (49 kPa) minimum at idle speed, and 43 to 64 psi (294 to 441 kPa) at rated full speed. The absolute minimum allowable limit at rated speed before mechanical inspection is 36 psi.
Yours is low. I would send off for an oil sample to get a feeling to igf it is shedding bearing material first, Then fresh oil fill and filter.

 

[TheOldHokie]

So to be accurate, here are the pressure specs for a 2203. For the Kubota V2203 diesel engine, the factory oil pressure specification is 7 psi (49 kPa) minimum at idle speed, and 43 to 64 psi (294 to 441 kPa) at rated full speed. The absolute minimum allowable limit at rated speed before mechanical inspection is 36 psi.
Yours is low. I would send off for an oil sample to get a feeling to igf it is shedding bearing material first, Then fresh oil fill and filter.

Your cold oil pressure is 50 PSI so its not your relief valve.

Dan

 

[North Idaho Wolfman]

Pulling the gear case is a 100% waste of time.
There is no plug (in the front) in the cam shaft.
you would need to pull the engine out and remove the sealing plug at the rear to see if the plug cam out.
And because the cavity that the plug would be in is sealed there wouldn't be a oil pressure issue because of this.
Also the plug being out will cause a consistent low oil pressure condition not a loss while getting heated.


The oil pressure relief valve is accessible from the outside again zero benefit to pulling the gear case.

If i was investigating this issue I would be pulling the oil pan and inspecting the pick up screen and pick up O-ring.
And you could inspect the rod bearings, you can not inspect the main bearings without taking the crack out of the engine.