Oil Level Check

[Pete]

On our 48 LRC we have DD 453N power. My question is what is the accurate process to check the oil level using the dip sticks. I would like a cold engine procedure as I usually check the oil prior to departure. Currently, if I check the oil cold after the engines have sat for 24 hours or more I will get about two quarts more than if I check it within an hour of stopping them. No doubt it has to do with an inverted high mounted filter and a high mounted cooler. The Velvet Drive 72C transmissions have the same problem, but I understand that they are to be checked after filling the cooler and before any drain down.

Today I start the engines for two or three minutes to fill everything full of oil, shut the engines down, wait about five minutes and check all the fluids. When I confirm the proper procedure, I will top everything off to the proper level and then remark the dip sticks for the cold/no start equivalent reading.

Pete Drez

 

[Genesis]

The BEST way is to ENTIRELY drain the system, refill with the specified amount "to capacity", run, let sit for whatever period (e.g. overnight) and then check it.

 

[MikeP]

Re oil levels: It's worth noting that many engines will tend to use a bit more oil if kept filled to the dipstick full mark as opposed to the add mark.

This occurs because as the oil level is raised, it is more exposed to crankshaft windage which will literally gather a blanket of oil mist around the spinning crank. The oil mist then adds additional vapor to the crankcase ventilation system and can be ingested into the intake system.

The windage is NOT caused by the crank dipping into the actual liquid oil which can destroy an engine and never happens unless someone has GROSSLY overfilled the oil. Windage is unavoidable and caused by the crankshaft turbulence forming a minature tornado within the oil pan. Performance engines use baffled oil pans, windage trays, and knife-edged cranks to reduce this. Tests on windage tray design in the 70's showed that crank windage in a non-windage tray equipped 426 CID engine at 7000 RPM actually caused a GALLON of oil to be wrapped around the crankshaft in a spinning cloud! Obviously, our DDs don't hit 7000 RPM - well, not more than once, anyway!

I can easily see the difference in my 8V71TIs' oil use based on filling to full or to add. If filled to full, the oil level will drop to a bit above "add" fairly quickly. But they will hold just above the add level for quite a long time. Consequently, I do what they tell me they prefer - I don't fill them beyond a touch above "add."

 

[REBrueckner]

Mike, thats an interesting comment on your TI's using a bit more oil when full. I never noticed that on mine (same engines) , but never thought to look closely either. What RPM are you running when you notice that effect?

I often run at only 1500 RPM and have on occassion filled my engines slightly above full...maybe two or three quarts. I did that that on a long run from Maine to Nova Scotia, about 13 or 14 hours. When I checked the oil after arrival it was still quite high as I remember....I did not add oil again for several weeks. So of course I did not bother "overfilling" on the return trip.

Anybody know typical oil consumption for 8V71TI's at, say, 1800 RPM? How about 1500 RPM? I think I usually add maybe 3 quarts at 20 or 22 hour intervals running at 1500 RPM, but don't take that as gospel...I'll have to reread my logs when I get aboard...

I also remember reading a DD engine manual, may have been 53 series, which stated that different installations use different dipstick markings...basically depending on the engine installation angle (incline). I'd hope that in a production boat, especially hatteras, they are marked correctly.

Regarding Genesis suggestion, which sounds logical, how does one know the "standard" engine manual recommended oil amount is right for a particular installation...installation angles differ...do oil pans also??

 

[captddis]

Generally running on boost about 1 1/2 to 2 qt every ten hours is normal. A tired engine may use a qt a hour!

 

[MikeP]

The critical issues with oiling systems is that the pickup ALWAYs be immersed and that the oil level not be so high that the crank can actually hit the liquid oil. Obviously, mounting angle and operational angle-changing have to be considered. Without proper baffling, windage trays, and hinged oil pickups, competition cars can easily move the oil in an oil pan to where it is not accessable to the pickup.

Virtually every car I owned - at least through the 80's, did this oil level thing. I always ran them "a quart low." Also, for reasons I've never understood, some engines of the same model seem to exhibit it more than others. We had a pair of high performance Mopar 340 engines built absolutely identically. You could fill them both with oil to the full mark. two weeks later, engine A would be nearly at "add" while engine B would be still "full." Burning oil! you say? Nope! Two months later, A was still nearly at add and B was still full. We used to joke that "A" was "hiding" oil in case it couldn't find any during the winter! None of us could figure it out.

I know this may sound stupid but I'm totally convinced that individual engines have personalities just like people. They will "tell" you what works best if you are listening. And yes, even stupider as this sounds, I have sat and "communed" with my hands on an engine for several minutes on many occasions before starting work. It seems to help. Is it a real "communication" or just some sort of mental adjusment on my part? I'm sure everyone would say it's the latter.

Re the oil usage on my 71s - I noticed it with the DDs when we ran at 1700 RPM quite a bit. But it didn't surprise me at all based on past experience. I run now typically at 1500 or less and have not actually checked again - I just never fill them to full. I check them twice daily when we're out and about, morning before starting and eve several hours after shutdown. Also kind of dumb, I guess. If I check them before starting why bother checking them after shutdown since the before-starting check will do the same thing? I don't know, I just do! And I can tell my engines like the attention!

 

[Pete]

REB, you hit on one of my concerns, the angle of installation. This combined with the design of the engine, where the oil pump is on the front of the crankshaft, with the pickup at least 2/3 forward in the pan and forward of a center baffle, leads me to want to be sure it does not run low on oil. At present I have 15 quarts of Texaco Ursa Extra Duty in each engine, and the dip sticks read full five or ten minutes after shut down. Anyone know what the spec is for oil capacity on 1976 453N with cast iron oil pans?

Pete Drez

 

[luckydave215]

As long as the oil level isn't high enough to be sucked up into a writhing alien by the crank, more oil volume is better. Remember, our (any) engines have a two stage cooling system. The hot parts first transfer their heat to the oil, which is then transferred to the water. (or air, in an air cooled design) Less oil volume can result in the oil having less "dwell' time in the system, thus not being cooled as much before once again coming in contact with the hot parts it's trying to cool. It only takes about a cup of oil to lubricate the engine, the rest is for cooling.

 

[REBrueckner]

".....I'm totally convinced that individual engines have personalities just like people. ... I have sat and "communed" with my hands on an engine for several minutes on many occasions before starting work. It seems to help."

C'mon Mike!!!! Does that help you or the engines? In any case, that is really WEIRD!! Get real!!!!

If anyone suggests that from time to time I may comment to my "babies" I'll DENY it. I will also DENY that it's most likely that I may utter a word of encouragement in their direction when wind and seas and fog and other adversities increase. Finally, after a harrowing experience I may utter a word of thanks/praise/to those "beasts of burden", but I will also DENY that.

I do not talk to mechanial devices..except to cuss; That's my story and I'm sticking to it.

I do acknowledge that I talk with my Yorkie when we cruise; that's bad enough!!!

 

[Nonchalant1]

I know this may sound stupid but I'm totally convinced that individual engines have personalities just like people. They will "tell" you what works best if you are listening.
Re the oil usage on my 71s - I noticed it with the DDs when we ran at 1700 RPM quite a bit. But it didn't surprise me at all based on past experience. I run now typically at 1500 or less and have not actually checked again

Mike,
I don't commune with mine but it definitely kicked my ass and laughed at me when I dropped that pipe plug into the oil pan.

Re: running at 1500 is really expensive for not much speed gain on my 53MY NMPG charts. I go 1300 or 1950 after I measured NMPG for each RPM in 100 increments last year. The result was an eye-opener.

 

[MikeP]

Well REB, as you correctly pointed out and I had temporarily forgotten, there is no shame in talking to engines; there is shame in ADMITTING you talk to engines!