What effects the engine oil capacity?

[Clement]

In looking at another thread: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=010671 where a poster asked if his engine would be hard on oil, I got to thinking about my cars. '94 Merc Sable 3.0L - 6cyl - 4.5 qts '87 Bonniville 3.8L - 6cyl - 4.0 qts '02 Accent 1.6L - 4cyl - 3.5 qts I always thought my Accent should hold more oil than it does, but looking at the above cars there is more oil/cylinder or per Litre than the two v6's. However, the 4-cyl runs a lot faster, about 3000rpm at 65 as opposed to the 6cyl's at a little over 2000 rpm at 65. I would think that the higher operating speed of the 4cyl would be harder on the oil and would require a larger capacity/litre than a 6cyl. Is this why as in the other post, I believe a Nissan 3.0L - 6cyl holds only 3.5quarts? Expected lower overall operating speed? That is a truck engine also, it just doesn't seem right.

 

[ALS]

Volvo recommends 4.3 quarts for my 1987 2.3 liter Turbo. The 1997 2.9 liter NA motor calls for 5.9 quarts. The Turbo 4 cylinder gets 1.87 quarts per liter while the 6 cylinder NA gets 2.03 quarts per liter. I guess they are working on the 2.0 quarts per liter with their motors. They also recommend 5K mile OCI's in both motors.

 

[John K]

A good question. I suspect that the designers do not really try to obtain a certain capacity on the drawing board, and that often it is changed as needed to get the engine into a certain space. That may be short sighted, but .... It certainly would be convenient if it came out to full quarts, but my Odyssey is listed at 4.6 qts. Why not 5??? If a manufacturer finds out that having a lower oil capacity has a negative impact on engine life over time you would expect them to take it into account for future designs, but somehow I don't think it works that way. Maybe I'm just being negative, that is what my wife would say.

 

[John K]

ALS - My Ody would be 1.3 QPL.........

 

[gudmund]

when doing a little math you will find that your Accent does have more oil in it per litre than the other two cars you listed in relation to engine size. 1.6Litre 3.5qts= 2.19qts per litre / 3.8Litre 4.0qts= 1.05qts per litre / 3.0litre 4.5qts= 1.50qts per litre / probaly does not mean much.

 

[jtantare]

quote:

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Originally posted by ALS: Volvo recommends 4.3 quarts for my 1987 2.3 liter Turbo. The 1997 2.9 liter NA motor calls for 5.9 quarts. The Turbo 4 cylinder gets 1.87 quarts per liter while the 6 cylinder NA gets 2.03 quarts per liter. I guess they are working on the 2.0 quarts per liter with their motors. They also recommend 5K mile OCI's in both motors.

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My 94 2.9 litre 960 also calls for 5.9 quarts but it always takes 6.5 quarts with oil filter change This engine turns 2100 rpm at 65mph.