Thread: SHO Engine...wet sump design !
09-11-2007, 02:38 PM #1
SHO Engine...wet sump design !
I just noticed in the spec chart, that the new Yammi 1812cc SHO engine has a "wet sump" design. That means it has a conventional oil pan like most automobiles . The other Yammi 4 strokes, including the HO engines, all have a "dry sump". Dry sumps have the oil stored in a separate container and the oil is pumped to the vital engine parts via oil pumps. I can't believe Yamaha made a PWC specific engine and then used old technology lubrication...wet sumps are not efficient for rough water and high cornering G force use. Honda as well as SD use dry sump designs. Kawasaki's 4 strokes have a "semi dry sump". Unless it is a misprint in the Yamaha literature, IMO, the new 1812cc engine might have a serious performance and reliability issue.
What do YOU think about this ??
09-11-2007, 02:45 PM #2
the Yamaha engineers are smart dudes - if they did this they did it intentionally
09-11-2007, 02:47 PM #3
I don't think it will be that big of an issue. Look at cars like my 2004 Z06, they pull over 1g of lateral acceleration in stock form. This doesn't even count what it will pull through a corner or what it can pull in both if modded.
I don't think rough water will make a bit of difference. Look at boats.....
Besides a dry sump system weighs more.
09-11-2007, 02:58 PM #4
Most race cars including the current generation Z06 Vette use dry sumps. Dry sumps might weigh a bit more but they allow for an lower engine height= lower center of gravity. Maybe thats why the deck in the SHO is so high ?
09-11-2007, 03:59 PM #5
It will be an issue, if it's a wet sump, AND you wanted to drop this down in a gpr...
09-11-2007, 04:25 PM #6
- Join Date
- Jul 2007
- Ponte Vedra Beach, FL
That can't be right, I mean if you flip the ski, wouldn't all the oil go straight to the heads and combustion chamber? Restarting that thing would be nearly impossible with all the oil that would coat the plugs.
Maybe they have some serious windage tray design that would prevent this???
NM, I got some info off google
Scavenger Pump Assisted Wet Sump: A completely new lubrication system has been developed by combining a compact air-liquid separation chamber and a scavenging pump to achieve and unprecedented reduction in engine size while providing the lubrication function necessary to accommodate a PWC's rugged use conditions.
And Yamaha's site
Wet Sump Lubrication: Uses two engine oil pumps to deliver lubricated oil to each moving part with water-jacketed sump and oil backflow protection.
It looks like they took the time to engineer a new oil system, which means it probably won't have the problems of older wet sumps.
Last edited by GP1300RnPVB; 09-11-2007 at 04:29 PM.
09-11-2007, 04:31 PM #7
I guess I didn't think about it flipping upside down! Lol!
I know what the current gen Z06 is. I know LSx motors like the back of my hand. I was just making a point that there are and have been a ton of corvettes that race with a wet sump system.
09-11-2007, 04:39 PM #8
Hope the pan has a few baffles in it to boot!!
09-11-2007, 05:34 PM #9
i hope there's a plug in the bottom of the hull to drain the oil for easy oil changes
09-11-2007, 11:19 PM #10
Easy fix !!! Depending on the oil pan design poss build a low cut pan and convert to dry sump... We do it on race bikes all the time,there will be a way around it i would think......However,i am sure that yami has it well designed like everything else they build.....
Last edited by james k; 09-11-2007 at 11:30 PM.
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