Another Low Oil Pressure Query

[Compass790]

Just wanted to add I have a 1/8" NPT ss tee in our Yanmar YSM8 single cylinder sender hole. It has the sender on one end & a fitting & "rubber" hose leading to a mechanical gauge. 6+ years in use. Needs threadtape or loctite to make good seal at joint as it should be a BSP tee.
No motor vibrates more than it ( well ok I'm exaggerating but it shakes a lot)
No argument that scubaseas idea about tees is mechanically much better just saying it hasn't been an issue for us . Our sender is very small tho.

[NNBill]

As Compass stated, the Yanmar JH series engines use BSP (British Standard Pipe), 1/8 X 28, vs NPT, 1/8 X 27. The taper is different too. There are BSP (M) to NPT (F) available.

[David Mathis]

Over the years and thousands of hours of use, engines wear. The simplest approach is to try an oil with higher viscosity numbers to see if it cures the problem or at least, make it a little better. If you're using 5-30, switch to 10-40. If you're using 10-40, change to 15-50, 20-50, or a straight 40 or 50 weight. If the problem goes away, the problem may be due to normal wear. The heavier oil may give you another few years before a rebuild is needed.

[Joe Okros]

If its good while cold and drops as oil gets hot, install an oil cooler,--the older Perkins used to run both the coolant and engine oil through heat exchangers. Or go up in viscosity to get another 2 or 3 thousand before a rebuild. It may also be a worn oil pump not pumping as much when the oil is thin.

[Shaneesprit]

Engine History:
27 years since installation;
Total hours 6658
Hours powering 523
Hours charging (at anchor or sailing) 6135

While charging we run it at 2000rpm and produce approx 80 amps of 12v DC, so it has some load.

Terrible Engine history’ I am afraid 😟
523 hours powering - perfect
Unfortunately engines are in no way suitable to be left ticking over - Charging 80A is nothing.
An engine manufacturer would state that you should have at least 50% engine load to use the engine.
Do not confuse RPM with load 2000RPM while charging means your engine is just running a high idle it is cold inside over fuelling and that’s a cause of engine damage.
Not sure on your engine but if you can rebuild or replace the oil pump, change the oil regularly and use it under Load to try and clear it out.

[a64pilot]

Diesels do not have to be run under hard load to survive, far from it actually. Majority of automotive Diesels spend most of their life loafing and last for decades doing so.
Generators that never exceed 1500 RPM are never under a heavy load, because they are RPM restricted, and no they are not special engines that are specially designed for low RPM.
Secondly what is it that you think that putting it under a heavy load will “clear out” from a low oil pressure perspective?
Lastly 2000 RPM isn’t “ticking over”
What is ticketing over is a truck idling all night long, and yet many used to do that every night, for years, not so much now to save fuel and pollution, but not to save the engine.

Now I’m one to often recommend to run one hard from time to time, it’s tests your cooling system and will help keep the combustion chamber clean. But I would never, ever suggest anyone who thought they had a low oil pressure problem to go run it hard, to do so would be asking for a bearing failure.

[a64pilot]

Originally Posted by NNBill

As Compass stated, the Yanmar JH series engines use BSP (British Standard Pipe), 1/8 X 28, vs NPT, 1/8 X 27. The taper is different too. There are BSP (M) to NPT (F) available.

Would you happen to have a source for these adapters? I looked and couldn’t find one, I’d like to put open or two in spares, just cause.

[NNBill]

Originally Posted by a64pilot

Would you happen to have a source for these adapters? I looked and couldn’t find one, I’d like to put open or two in spares, just cause.

Let me dig through my paperwork and see if I can find where I got them from...

Bill.

[NNBill]

Originally Posted by a64pilot

Would you happen to have a source for these adapters? I looked and couldn’t find one, I’d like to put open or two in spares, just cause.

Here is an Amazon link:

https://www.amazon.com/Dewhel-Female...KDM2EFKDNW8QH8

[a64pilot]

Originally Posted by NNBill

Here is an Amazon link:

https://www.amazon.com/Dewhel-Female...KDM2EFKDNW8QH8

Thank you, that ought to help some that don’t want to tap their blocks, if I could have found this adapter, I wouldn’t have either.

[Compass790]

Heres a cheaper alternative if you are not in a hurry
https://www.aliexpress.com/item/4000...archweb201603_

[jimbunyard]

Originally Posted by wingssail

...After reading my update would you still recommend flushing the engine, and exactly how should I do that? and how many times do I change the oil afterwards to get the diesel and "stuff' out?

At this point no. Using diesel as a flush, I change it at least twice.

Originally Posted by Scubaseas

...It's just a redundant set up which is kinda stoopid in my opinion.

Which might show how much you know about the subject.

Umm because they work on the exact same principles regardless of the manufacturer.

Because "they work on the exact same principles" doesn't mean they perform the same function.

If you want to believe they are separate things and work differently I am not going to change your religion. If you need to be right, fine your right

I fear your use and understanding of written English is about on par with your mechanical knowledge. Not sure what my right has to do with anything, but if you mean my being right, that has nothing at all to do with it. The OP is asking questions about things he has less information about than others have. It's important to give the most accurate information possible to ensure the most complete understanding in the shortest amount of time. Inaccurate or incomplete information is at best confusing and a waste of time.

Originally Posted by wingssail

OK, I'm taking this all on board and I'm glad to have experienced people giving me the benefit of your experience. On this topic I have little.

OK I've probably not got an oil pressure problem except remaining concern about the oil supply to the rockers. I'm going to pull the rocker cover off, (I've done it before to replace ahead bolt) and observe the oil flow all along the rocker shaft.

I will add an engine flush product and follow the directions in the hope that the passage to the rockers will open up. I will change the oil at 100 hours (or there abouts).

I will not add a T, (very good points on that, thanks) and I will get properly sized yanmar sending units (it just means waiting, importing in Mexico is slow).

An with that I will end this thread so as not to bore you all with what might well have been a false alarm.

Thanks Again

(Now I have to go replace my 10 year old blown up charger/inverter. Do projects ever end?)

As others have noted, the oil supply to the rocker shaft is important, so perhaps it is good to go into it in a little detail. The oil supplied to the shaft oils the interfaces between the rocker arm bushings and the shaft, the valve tip and the rocker arm, the pushrod and the rocker arm, the pushrod and the lifter (tappet), the lifter and it's bore, and in most cases a percentage of the interface between the cam lobe and the lifter face. (The rest is supplied by 'splash' from below.)

So adequate supply is important.

I think your idea of running the engine without the valve cover on is good. If at idle things get messy pretty quickly you're probably good. If you don't see oil quickly, rev it up and see if the flow improves. If it does there may be a restriction somewhere, there could be wear (but I'd bet against it, based on the pressure you're seeing), or it could be an artefact of the engine's design (well that's helpful). If you see a good flow above idle, I wouldn't worry about it.

If you don't see a good flow above idle, we're kinda back to square one, and I'd either remove and clean the regulating valve or do the engine flush, probably under the 'whichever is easiest' guideline.

As for flushing, follow the instructions supplied by the manuacturer of the product you select. I don't think any of them will recommend running the flush for 100 hours, if that's what you intend, though I assume you mean you'll change the engine oil at 100 hours after the engine flush procedure is completed. My suggestion of using diesel was made because that's what I do and I know it works. There is the problem of disposal though, which I solve by putting it off; it goes into a plastic 55 gallon drum reserved for the purpose.

[Scubaseas]

jimbunyard. Sorry if I offended you. I am an retired ASE certified master mechanic with over 50 years experience, ran a very busy foreign car repair shop for 38 years, am a former ABYC member and have a background in mechanical engineering. I have been repairing boats for about 30 years. And you're right, I'm not a good writer. Your bone fides are?


If I could have found find a discourse on Yanmar's dual spring oil systems I would have used that as an example. Same operating mechanism and principle as the VW from what I can tell. As in a second regulation of oil pressure down stream of the pump. Is a pressure relief valve used as a method of pressure regulation or does a pressure regulation valve offer pressure relief? Is an ignition coil technically a solenoid?



The dual spring and piston system is either there to bypass the filter or to regulate the pressure to the oil cooler and turbo (if fitted). Your theory of dual spring regulation is?


If you don't like what I have to say or how I say it maybe don't read it. Sorry if I disagree with you. But I respect your right to say it.

[skipperpete]

Thanks wingssail, good threads are made by good OP’s just as much as all the interesting and well thought out responses, good feedback and a happy result.
Pete.
I learn something new each time I visit the forum[emoji41]

[wingssail]

Originally Posted by jimbunyard

At this point no. Using diesel as a flush, I change it at least twice.
…
As others have noted, the oil supply to the rocker shaft is important, so perhaps it is good to go into it in a little detail. The oil supplied to the shaft oils the interfaces between the rocker arm bushings and the shaft, the valve tip and the rocker arm, the pushrod and the rocker arm, the pushrod and the lifter (tappet), the lifter and it's bore, and in most cases a percentage of the interface between the cam lobe and the lifter face. (The rest is supplied by 'splash' from below.)

So adequate supply is important.

I think your idea of running the engine without the valve cover on is good. If at idle things get messy pretty quickly you're probably good. If you don't see oil quickly, rev it up and see if the flow improves. If it does there may be a restriction somewhere, there could be wear (but I'd bet against it, based on the pressure you're seeing), or it could be an artefact of the engine's design (well that's helpful). If you see a good flow above idle, I wouldn't worry about it.

If you don't see a good flow above idle, we're kinda back to square one, and I'd either remove and clean the regulating valve or do the engine flush, probably under the 'whichever is easiest' guideline.

As for flushing, follow the instructions supplied by the manuacturer of the product you select. I don't think any of them will recommend running the flush for 100 hours, if that's what you intend, though I assume you mean you'll change the engine oil at 100 hours after the engine flush procedure is completed. My suggestion of using diesel was made because that's what I do and I know it works. There is the problem of disposal though, which I solve by putting it off; it goes into a plastic 55 gallon drum reserved for the purpose.

Thanks again, as usual, I find your advice thoughtful and thorough.