The component in the photo that is close to the sensor wire is an aluminum carb heat or cabin heat muff. The aluminum muff won’t be hot enough to damage the wire if it is secured per normal practice. In many such installations a bypass valve is used so the muff is continuously cooled by internal airflow even when heated air is valved ‘off’ by the pilot, making the aluminum muff the same temperature as the air flowing out of it. That helps the muff last longer.
Silvaire if you zoom in properly on the photo you’ll see the drain plug is close to the heat muff but even closer to the unadulterated and uncooled exhaust pipe.
Shorrick_Mk2 wrote:
The fact that we run an engine with 12 (twelve) quarts of oil when in fact it is perfectly happy with three gives you an idea of the (allegedly) yet unsurpassed design quality and job adequacy.
That’s not quite accurate as the 9-12 quarts is a company requirement, not an AFM requirement.
Peter wrote:
so nobody should fill above 9 anyway,
This would normally only happen during scheduled maintenance. Normal day-to-day flying it’s kept up at 9.
Peter wrote:
The other is that the airworthiness limit is 1 quart per hour (!!) so filling to 9, or even 12, is necessary if you fill up your plane to full fuel but want to arrive with just enough oil in the engine.
I had a look and yes I do have a spare drain plug location on the RHS of the engine bottom/
Is this a minor mod?
It would be really good to have.
This week there was an emergency of a piston PA46 with a ferry tank installation on a world circumnavigation. The pilot lost oil pressure at FL100 after takeoff.
As part of the ferry tank installation, they also installed an additional oil reservoir to comply with the 1 quart per hour max allowable consumption figure. If you increase the endurance, you also have to increase the sump size. Unfortunately the installation was very badly done and the oil line from the extra reservoir ruptured and the engine threw all its oil overboard.
My airplane also has an unnecessarily large sump because it carries oil for 7 hours. I never fill in the 9qt it is supposed to get but do 6qt instead as it will throw it overboard anyway in not much time. I do not see a lot of failure modes where an engine would suddenly increase its oil consumption from 0.05qt/h to 1qt/h — I see a lot more scenarios where the oil consumption would go to 1qt per minute…
Yes and that is where a level indicator would give you perhaps enough of a warning to land somewhere, rather than have no warning till the EDM700 starts flashing that the CHTs have hit 500F and then the engine makes a funny noise and stops.
My airplane also has an unnecessarily large sump because it carries oil for 7 hours. I never fill in the 9qt it is supposed to get but do 6qt instead as it will throw it overboard anyway in not much time. I do not see a lot of failure modes where an engine would suddenly increase its oil consumption from 0.05qt/h to 1qt/h — I see a lot more scenarios where the oil consumption would go to 1qt per minute…
Like many people I run my Lycoming a quart below maximum for the same reasons. However I can conceive of failure mechanisms that would somewhat increase oil consumption without affecting the engine too much otherwise. I think a cracked oil ring on one piston might well do that. However, I don’t think it’s likely enough to carry around excess oil.
I am investigating that oil level sensor and will report on what I find.
Update: a US engine shop has measured the space in the sump on an IO540 and says it will fit, so I am going to order one.
The consensus is that it is a Minor Alteration.
What are the rules for a separate CB? The current would be something like 50mA (just the LED).
Peter wrote:
a US engine shop has measured the space in the sump on an IO540 and says it will fit
I hope the shop was “most reputable” 
I am very sceptical about such things. It’s a rare modification. What if the sensor breaks, starts to leak, etc. and you lose all your oil in one go? That’s a risk and there is almost no benefit. Is the LED illuminated all the time and would go off when the level is below? If an indication is PROB80 a sensor fault, would it do much good? You are flying over Lampukistan, get the indication and land at the Lampukistan airforce base where you get thrown into jail. All for an obscure sensor that failed…
