Oil Sump Size is small Great?

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In the UOA section the Nissen 1.8L has a 2 3/4 quart capacity. This got me thinking. Would this be a real plus as the oil gets to operating temp very quick and stays there. UOA have been very good on these cars. Both my older cars have 6 quart capacities. My new Miata has a 4 quart which seems to do well. Is this a trend? Is this why we are seeing smaller oil filters? My old 1952 Jaguar took 18 quarts. Things are sure changing.
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There are space constraints that restrict how large the filter & pan/sump can be, considering the same engine is often used in various vehicles. The shape & size of the pan may also be dictated by lubrication needs - too small and there might be too much oil frothing. Generally speaking, though, higher-capacity systems are more desirable, if for no other reason then that there is greater reserve capacity for heavy-duty and extreme use, and greater safety for low oil conditions.

Smaller oil capacities isn't necessarily the trend. My 2.7L car engine has a 7.3 quart capacity, for instance. Some cars & trucks go to 12 quarts or more.
 
It might get up to temp quicker, but that doesn't really make it better. It will also cool off faster, so if you're in the store for, say, half an hour, the engine is going to be cooler than if you had 6 quarts. Also it's going to stay cleaner and have more reserve as williar said. I'm going to be installing dual remote filters on my cherokee soon, hoping to add at least 2 quarts to the total capacity.
 
Small is bad. The oil won't get to temperature until the water temp is up. This engine has the smallest sump in any small 2L engine. On the plus side this engine seems to do well in terms of durability and oil analysis. I would make sure the oil level is always toped off.
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Although it takes a bit longer to warm up (a bad thing), I'd think that less sump capacity is NOT a good thing, simply because the oil will contaminate faster. As for ever-smaller sump capacities, I suspect the following:

1. As we'd all figure, smaller engines require smaller sumps -- no surprise there.
2. Smaller cars mean smaller engine compartments, meaning smaller sumps and smaller everything.
3. Newer engines tend to contaminate their oils less due to more sophisticated sealing, somewhat tighter tolerances, and longer overall engine life.
4. Newer oil base stocks and additive packages are better able to cope with contamination, therefore requiring less oil to accomplish same.
5. Typical oil filters have gone from 35-40 micron filtration of two decades past to about 25 micron today, better keeping particulates out of oil.
6. As mentioned before, we're seeing good UOAs and engines lasting longer in spite of this, so none of this is detrimental in the big picture.
 
quote:

Originally posted by TC:

3. Newer engines tend to contaminate their oils less due to more sophisticated sealing, somewhat tighter tolerances, and longer overall engine life.


IMO they contaminate their oils less predominantly due to far finer fuel mixture control and unleaded fuel compared to older carbureted engines.

In the '60's many US built V8 engines held 5 quarts with filter. Today's 4 cyl 4 quart capcities using unleaded fuel, lower fuel burn rate, and fuel injection must be very easy on the oil by comparison.

I appreciate larger pan capacities. More oil to dilute the blow by products. My PSD engine holds 15 quarts and once you're under the truck anyway might as well change a LOT of oil.
 
my dad has a 03 nissan sentra 1.8 L 27k miles. everytime he goes to walmart to change oil. they always overfill and put 3.5 quarts in there.
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quote:

Originally posted by Cutehumor:
my dad has a 03 nissan sentra 1.8 L 27k miles. everytime he goes to walmart to change oil. they always overfill and put 3.5 quarts in there.
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Yeah overfilling does not make for the best UOA's in some cases that's for sure . This is but one of the variables that we see as inconsistency of engine oils used here .

I like the small sumps on both my Son's and my own Miata's . 3.5 quarts fills them exact and my Wifes little commuter " Kia Cinco " gets 3 quarts at oil change but it's a dino killing little fella in summer
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as opposed to the Miata's " same engine block " that have different cam timing and run a tad cooler with a more open engine bay and no automatic transmission that increases demand on the motor .

If a guy was so inclined he could install a Fumoto Drain Valve and drain off a quart of low cost dino per month or more and extend full drain intervals with filter change for a period simalar to synlubes at much less cost ....
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New idea? My 1968 VW 1500 has a 2.5 sump and no oil filter. The engine displacement is small by todays standards, but with a carb and loose clearances due to air cooling, there is a lot of blowby contamination. These things seldom lasted more than 60-80,000 miles between overhauls.
 
TC probably did the best job itemizing why we are seeing this ... and why it's an OK trend (in general).

Also, some car companies seem to be really thrilled with a low "cost of maintenance" so we see longer recommended drain intervals along with the reduced sump sizes. In the grand scheme of things, I don't see this as significant in the real world.

And I wouldn't be surprised if there weren't some "green" aspects to this trend as well. Less oil in the sump = less used oil to deal with.

Me? I want a 5+ quart sump even on a small 4-cyl engine ... and while you're at it gimme an oil filter the size of a coffee can jam packed with an ultra-dense filtration media.
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--- Bror Jace
 
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