Farymann K34 oil pressure

[JordanH]

Hi All,
I'm looking for the actual or 'real world' oil pressures for a Farymann K34 diesel circa ~1983.

You may have read my story from last week regarding low oil pressure in my new-to-me Contessa 26 so I'll spare you the long version.

Presently, the oil pressure is around 10psi at idle and 15-18psi when running full bore and hot. The previous owner claims that's "normal". The oil pressure light starts blinking around 18psi and is on solid red around 15psi and the previous owner claims that's because he installed the incorrect oil pressure light. He tells me I, "just don't know the engine and it's fine to run at those pressures."

I've found conflicting information about what the actual pressure is supposed to be; I have a physical manual for an 18W (similar engine) which states 7psi at idle and 22psi when running at full revs. However, this link from Farymann contradicts the manual and states that 1.8bar (14.5psi) is the minimum ( http://tinyurl.com/5tgnu9u ). However, the latter link looks incorrect as it states the K34 is a 5.8hp engine, not the correct 7hp engine that I know it is.

So... for you folks that own them, have owned them or work on them. I would like to know what ACTUAL oil pressure you see at idle as well as what the oil pressure is when you run at full rev's.

I'll be calling Farymann as well as two knowledgeable mechanics tomorrow and will post the results.

Thanks,
J.

[johnnyandjebus]

Jordon

My shop manual says
The oil pressure at idle speed should be at least 0.5 bar(7PSI). At full load (2850 rpm and 100 degrees C oil temperature) it should be at least 1.6 bar (23 PSI)


John

p.s my shop manual is for the K34 but does not state a year, I doubt, but do not know, that the engine changed much over its life.

[JordanH]

Thanks John,
I think I may be looking at the same (or similar) shop manual.

This tech data PDF ( http://www.farymann.com/technical_da...after-1981.pdf ) seems to contradict that, does it not? What am I missing?

Now to convince the seller that 15-18psi at running revs is not good enough.

[johnnyandjebus]

Jordan

The PDF you linked to sure does contradict the manual, Although it does group the K34 with several other engines....

As to the previous owner, no advice for you there, but I do have a couple thoughts;
Would the viscosity of the engine oil have an impact on oil pressure at the rated temperature? I assume that it would. Are you running with the recommended oil?
You mentioned running hot, My engine does not have an oil temperature gauge so do you know what the oil temp is when you measured the PSI?

Not suggesting you do or don't have a problem just some things to consider.

John

[JordanH]

I'm running SAE 30 which, I believe, is in spec. I'll go back and take a look, but if I recall correctly the docs say SAE 20 for colder temps and SAE30 for higher temps. It's new, clean and not dropping in volume.

When I mentioned "running hot", I meant while the engine is at temperature. For the first 30-40 minutes, the oil pressure starts around 80psi and falls to its eventual state below 20psi. I didn't mean to imply it was a particular temperature.

I'm attempting to track down some other Contessa owners to see what they run at.

[JordanH]

Just a quick update.
I haven't heard from Farymann themselves yet; However, I did speak to Entec West who was recommended to me by a variety of sources as being "the" best source for information on Farymann engines. The fellow I spoke with was very helpful and gave me a whole history lesson on the company, engine and details. He sounds more than qualified to answer this simple question.

He tells me that the original K34's had an oil pressure release valve that was set extremely low and would quite happily run on oil pressures down low into the 3-5psi range and that I shouldn't worry. He didn't see the technical numbers on the Farymann website but he suggested that they are not applicable to my engine as I described. Although the manual states the pressure should be 23psi, he tells me that I'm perfectly fine to be running in the 15-18psi range.

The quality and content of that message makes me feel quite a bit relieved. Apparently the previous owner is correct and that I should be ok... although I should replace the idiot light so that it is not always "on".

Incidentally, the mechanic suggested that the only reason this vintage of raw-water cooled Farymann was still running is that it's been kept in fresh water all these years. I may not get to snorkel in reef's on a daily basis like you guys in the islands, but at least this cold water has preserved my engine. :-)

This answers my question, but I'll update this thread if I receive more information.

[celenoglu]

The oil pressure release valve of Farymann is a simple device and normally keeps the pressure stable. In my case a small piece from the oil filter was broken and that small piece find a good place to hold the release valve forever meaning low oil pressure. I donot know the exact figures bu a decrease in pressure is not good.

[JordanH]

Resolved! Whoo-hoo.
Well, we pulled the engine and replaced the oil pressure pump. The engine runs well now and keeps the oil pressure around 21-22psi under revs and around 12psi at idle. Not too shabby for a 27 year old lump.

I had it out for 2 test runs, one 40 minute run in dense fog (oops, forgot the GPS, thank goodness for radar!) and the second was a sunset cruise for an hour of motoring. It all looks and runs well at this point.

I think what was happening was that the oil pressure valve was stuck 'closed' before. On startup, it would raise to 80 then 90+psi (which I'm told is abnormal and way too high) and then poof, it would start it's sharp decline. So perhaps that 90+psi pushes the pressure valve open and then never reseats properly allowing oil to continuously leak out. I took a look at the device and it's simply a spring loaded "flap" like valve; As celenoglu says, a simple device.

Nothing more to see here.