Anyone Use Oil In Their Pump?

[robertg]

I am cleaning my Skat Trak pump on my Superjet and I am thinking of putting oil it it, instead of grease. In my opinion oil is a better lubricant. Has anyone tried this?

[Matt_E]

Whenever I get smart ideas like that, I can't help but wonder why the manufacturer didn't think of that.

[robertg]

The only disadvantage I can see is the oil will leak out easier. I have my pump out a few times a year so it would be easy to check. There must be other reasons why Yamaha uses grease.

[Jr.]

It's not the oil getting out, but the water in! I tried it. works great short term,nice performance improvment.
down side is, no matter what I did, I always had water in only a ride or two. I changed seals & o-rings, no differance. With grease & the same o-rings & seals, no problem. Never did figure out why?
The oil I used was the Klotz jet pump lube.

[2XLR8]

A nice performance improvement? You would have to feel the performance for it to be considered an improvement. I just can't see how you could notice an improvement by just switching to oil over the grease in the bearings.
Have others seen similar gains? with this mod? Someone has to do a before and after test within an hour or so to be able to tell if there is a gain.

[Idok]

the lesson to be learned is that whenever cracking open a new/strange pump to you always do it over the garbage can as you never know if the guy BEFORE yoiu put in oil or grease....

[crammit442]

well, its obviously something you can feel if its a performance improvment. otherwise, it wouldnt really be an improvment.


You can easily turn a superjet drive shaft with 2 fingers with new bearings/seals. We're talking about a few inch lbs required to turn the shaft at most. You really think you could actually feel the very slight reduction in friction? How much less friction are we really talking about anyway.:rolleyes:

Charles

[crammit442]

just take any bearing and wash all the grease out of it and pour in some oil and turn it by hand. youll feel the difference. it will "coast" quite noticably longer. now translate that your pump bearings. nobody said it was "big performance gains". collectively, between things like billet kawi style couplers, lightened flywheels, titanium/lightended shafts.... and oil in the pump instead of grease, youll gain performance due to less mass and/or less resistance. personally, i dont like doing it just for the reason that paul stated.... water seeps in.... just like on a POS seapoo pump that need to be rebuilt every other ride. its not rocket science.... or prosthetic surgery:rolleyes: :rolleyes: :biggthumpup:


I don't claim it's NOT a difference. I'm just not sure I believe it can be felt as a modification by itself. If a given setup makes 50 ft lbs of torque(600 in lbs) you're telling me you can FEEL a reduction of a couple of in lbs?:rolleyes:

Charles

[crammit442]

how many rpms can you spin a pump at w/ your fingers? the engine turns the pump at a much higher rpm than you can achieve with your fingers, or else youd be a porn star. the resistance created by pump is multiplied at higher rpms just like its easier to walk through peanut butter than it is to run through peanut butter. replace that peanut butter with oil and then youll see where im coming from with this highly scientific analogy.


Do you actually have experience with walking and running through peanut butter? Where'd you ever get such a quantity of peanut butter?:haha: Seriously, how do you quantify such a small "improvement"?:rolleyes:

Charles

[Matt_E]

Thanks for a good Saturday night laugh.

Now excuse me...but the Peanut butter store just called.:biggrin:

[2XLR8]

I don't think you can feel any performance gain. If you did it would be more of a placebo effect. If you figure a certain engine combo is delivering 145 horsepower and you are going 63.5 mph on a particular hull.How much slower would you go with one horsepower less? And could you even feel one hosepower less. I dont think you can. Now if we use a 1/8 (or less) horsepower electric motor and we gear it accordingly we can spin that driveshaft way faster that that engine ever will. Im not saying that it wouldn't go faster if the bearings had oil instead of grease just that it takes so little horsepower (or fraction of one), to be of any significance

[Mile9c1]

You'll never see a difference, the grease melts when the pump is running so after a few minutes the difference would go away even if there was a difference to begin with (which I don't think there would be).

The grese from the factory is not very thick at all.

[jura]

This is the third season I have ATF oil in my superjetpump, no problems at all.
No water in the pump and no oil-leaks.

Greetz from Belgium.

[2XLR8]

There are lots of opinions on the gease melting or not inside the pump in watercraft. On cars the wheel bearings will heat up to melt the grease. the pump has a cooling effect of the water running through the pump on an aluminum housing to dissipate heat. There is also a whole lot less load on the pump bearings. In my own personal opinion I don't think it does. I base this on the solidified grease pattern you see on the inside of the rear cone. If it was liquid and then cooled down you would see clearly a level where the grease hardened during the cooling period. Every time I look at pump bearings there is always solid grease around and near the outer race of the bearing.

[Mile9c1]

Every time I look at pump bearings there is always solid grease around and near the outer race of the bearing.

True, I see that too. There was a discussion a few years ago on the old board about how much bearings heat up and the I didn't think they'd get too hot because of the cooling water, but some peeps said they got pretty hot (enough to breakdown the clear PPG pump cones).

Either way, so little of the grease stays on the bearings that it wouldn't "waste power" IMO. Npw sealed bearings are a different story.