What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

What is correct oil level to calibrate dipstick ?

Larry DeCamp

Well Known Member
I had to shorten the fill tube to clear the James cowl with my Superior -360 engine. I need to reposition the dipstick ( with the tail down of course).

I have concluded that the oil measured in the sump is the quantity available to maintain supply at the pump intake, and minimums are suggested by the manufacturers.

I have observed that filters are check valved and do not drain back to sump nor does the oil cooler. So why not put 4 quarts in the sump, or 6 and set the dipstick mark that corresponds ? You want to know how much is available to the pump no matter where the rest of the oil in the system resides after start-up. Yes/No ?
 
I have an IO-360 that I want to add at 5 quarts. At oil change I drain oil and change filter. Then I add 5 qts start, warm up and check for leaks. I let it sit overnight on the tailwheel and check it just like I would do before a first flight in the morning. I mark that level as 5 qts and then add one more and mark that level as 6qts, my add and full lines.
 
IMHO, a dipstick with actual qty markings should show sump volume, not system volume. What is in the rest of the system is not relevant when checking a sump, as it's purpose is to know the reserve capacity in the sump. If someone is doing an oil change and filling based upon the sump volume only (i.e. not considering the volume needed for things like filters) really shouldn't be doing oil changes by themselves. I calibrated the stick on my 540, as I had to shave down the tube and re-thread due to wear (started with a core). After an oil change, I just added a quart then marked the stick. rinse and repeat up to 6 quarts. Then engrave the stick accordingly. You need to engrave right away, as the oil will tend to make the sharpie marking disappear.

Larry
 
Last edited:
Back
Top