Does a dry sump engine have two oil pumps?

[75450]

Does a dry sump engine have two oil pumps? One to force oil thru the engine and a second to scavenge the sump oil over to the external oil tank?

[jstrube]

Does a dry sump engine have two oil pumps? One to force oil thru the engine and a second to scavenge the sump oil over to the external oil tank?

Or more...

https://www.knowyourparts.com/techni...m-differences/

Pretty interesting stuff.

[AlanColes]

Does a dry sump engine have two oil pumps? One to force oil thru the engine and a second to scavenge the sump oil over to the external oil tank?

No need for more than one.

Every pump I can think of quickly does both functions (sucks and blows) so it is simply a matter of what the specific application requires. You can run a dry sump with just one oil pump or multiple, however, each additional pump adds an additional, potential failure point and wear point.

Here is a diagram of the oil lines, etc., for my Norton Commandos:
Oil lines - Norton Commando.jpg

Blue lines are the feed lines and run from the oil tank (sump tank) to the oil pump (lower right).

Red lines are the return lines and scavenge oil from the crankcase, etc.

Think blue = cold oil and red = hot oil.

The transmission of a "unit" construction so separate from the engine and has it's own oil with no pump so as you can see there are no feed or return lines to it.

[75450]

Thanks for the responses.

This is interesting: https://en.wikipedia.org/wiki/Dry_sump

A dry-sump system is a method to manage the lubricating motor oil in four-stroke and large two-stroke piston driven internal combustion engines. The dry-sump system uses two or more oil pumps and a separate oil reservoir, as opposed to a conventional wet-sump system, which uses only the main sump (U.S.: oil pan) below the engine and a single pump.

The Norton pump may actually consist of two pumps ????

[PoorUB]

I have no idea how it can be done without two oil pumps. The two pumps might be in one housing, like a Harley. I know when you shop for a Harley oil pump it is one pump but it has two sets of gears.

[PGlaves]

I have no idea how it can be done without two oil pumps. The two pumps might be in one housing, like a Harley. I know when you shop for a Harley oil pump it is one pump but it has two sets of gears.

The Oilheads have a double chamber pump. High volume low pressure for cooling and high pressure low volume for lubrication.

[lupinblue]

I had a YamahaTZR250 two stroke that had two oil pumps: one for engine oil feed, one to pressurize the gearshafts in the gearbox. I think the TZ series race bikes had the same setup. Irrelevant, but interesting!

[75450]

. . . one to pressurize the gearshafts in the gearbox.

Interesting. Just curious . . . what does this mean? Why is it done?

[lupinblue]

I understand the reason was to use lighter components/reduce drag in the gearbox. It seemed to work - the bike was a little rocket if you didn’t mind no power until 7,500 rpm then a mighty rush as it came on the pipe!

[lupinblue]

Here’s a picture: