Grease vs. Oil

[midpw]

When is the decision made by the made by a manufacturer to use a grease cup for a bearing point vs. an oiler? On my engines the crank bearings are greased and the faster parts are oiled.......

My questions comes up from a "water motor" that is now in my shop. This thing is powered by a flow of water and has an output shaft on either side. It turns at a relatively high speed (guessing 3-400 rpm) with a garden hose supply to the inlet. I want to power it with a smaller (1 3/4 hp Nelson brothers) hit and miss and a rotary vane water pump. that I have rebuilt.

ANYWAY..........the water motor had what appeared to be grease cups on both bearings but the caps are gone and there is a "steel wool" material shoved in the cup(s).

Should I grease these bearings or use oil??

This water motor thing is kinda neat, anybody seen one?

 

[Jim Tremble]

My questions comes up from a "water motor"

Is that a Pelton Wheel ?? Can you post a photo for us ?? If not, send me a photo and I will post it for you.

Thanks,

Jim

 

[Steve Barr]

Here is a Chicago Water Motor

and a larger Backus Water Motor

and an earlier Backus Water Motor.

 

[Steve Barr]

Here is a pic I found of a Pelton Water Moter...it has oil wells instead of grease cups.

This was shown at the Coolsprings Power Museum Fall Show '04

 

[midpw]

So anyway...................

What about the grease or oil thing?

Is oil for higher speed bearings? Or does it really matter? This water motor that I am restoring is given to me on the condition that I don't goof it up and that I never sell it.

So I wanna do it right ya know?

 

[CharlieBiler]

So anyway...................

What about the grease or oil thing?

Is oil for higher speed bearings? Or does it really matter? This water motor that I am restoring is given to me on the condition that I don't goof it up and that I never sell it.

So I wanna do it right ya know?

So you want someone else's opinion, even a dumb one? Use Lithium 'cup grease'. I reccomend Century ST-80 part#157621 . It will stick to everything, has excellent lubricants, and it gives a good film. Do not use plain white grease. A good second choice is Kendall 427 super blue. It is an excellent lube but it is a little thick. It was developed for high temps in wheel bearings, but it is engineered with a little extra 'tackiness' for things like fifth wheels and distributor cams. It sticks like crazy and turns your hands a pretty blue.

You are correct. Oils are for higher speeds and grease is for slower speeds and cool temps. Grease is a combination of soap and oils, and sometimes a filler like graphite, sulphur, moly, teflon, or something else. I am not talking about Grandma's lye soap. I am talking about lithium soap, aluminim soap, and other soaps. If you are going to use oil, DO NOT USE ENGINE OIL. Use type SB oil for lubrication.

Sometimes they use grease because there is a need to prevent 'washout' in bearings and friction points. Some engineers do not seal with seals or slingers and oil might be washed out with water. Have I throughly confused you? Good.

 

[Jebaroni]

I used to work at a grist mill and we used regular grease gun grease to lube the water wheel bearings. As others have said, it works good in a low speed, low temp environment. I would personally feel more comfortable using grease instead of oil as I would fear wash-out with the oil unless I took the whole thing apart and personally examined the seals at the bearings (if there are any). It's hard to wash out grease.

 

[Andrew Mackey]

Grease as made in the 'old days' was a mixture of either heavy distillates or had a parafin (wax) base. Greases were for slow speed bearings, and in the case of the water motors and 2 cycle engines was also used to seal the bearings from transfer (water or air) from the outside of the cases to the inside. Plumbers water pump grease had a parafin base, and did not wash out or dilute with water. Engine greases were heavy distillates, more closely related to tar, and would run out of the bearings if they got too hot. These greases had a good 'stick to-it-ness' (adhesion) that was lost with heat. Ever hear of a 'hot box' in train lingo? It was a wheel truck bearing that got too hot from lack of grease. Anyways, DO NOT use soap based greases on the water motors of 2 cycle engines!!! On the water motors, it will degrade and wash out of the bearings, causing excess wear and leakage. On the 2 cycle engines, gasoline or oils will cause a chemical reaction within the grease, it will turn into a corrosive goop that will promote electrolytic reactions between the crankshaft and the bearing metal - be it bronze or babbitt or what ever, it will cause major damage! Also when the grease degrades, it will allow air to infiltrate the bearing, which will cause the fuel-air mixture to be leaned out. This lean out will make the engine idle poorly, and cause a loss of power. Also, the degraded grease will not lubricate either, even though it still looks good. I almost ruined a 1909 Detroit engine works stationary engine by using a soap based grease on the engine mains. Although fuel in this engine never gets in the crankcase on this engine (it has a fuel injecter, the oil from the piston and crank throw bearings was, and this oil degraded the grease. A parafin based grease would eventually be diluted by the crankcase oil as well, but it still lubricated the bearings! The new soap based greases become erosive when contaminated by oils. READ THE LABELS !!! Som soap based greases actually have a warning on the labels about this incompatability. It will probably say somthing like 'be sure to remove all old grease before installing this product'. It is a warning that should be heeded
Andrew

 

[BillsToys]

As a chemist I agree with what Andrew has said. I may be lucky but have had good success by going to a boat store and using a marine grease for my water pump.
Bill

 

[Jim Hunter]

I'm not saying that somebody didn't change them before I got them but both my oil field engines came with oilers on crank bearings and zerk or greaser on rod bearing. Unless I'm mistaken these both will be turning at same speed. Should I change one or the other. Have the one running and it seemed to work ok, but I'm new to this ! Also why not motor oil in these bearings? Jim

 

[Andrew Mackey]

Older grease fittings were Alemite. Later Zirc fittings were faster to use, but if the check ball hung up you had a mess! Oilers on mains have to be monitered, as oil flow will change with temperature. Grease just hangs in there. As far as an oiler on the crank-pin throw, the oil would be thrown off by centrifugal force. Unless you have a closed crankcase, an oiled crankpin can get real messy. Some engines had an oiled crankpin, Reid for instance, where the oiler was mounted on a pedistal, with a wick that allowed the oil to be wiped off the wick, by the connecting rod. This system though did not favor bearing life, however, as any airborn dirt, dust. or bugs that settled on the wick, usually ended up in the bearing!
Andrew

 

[midpw]

Once again you guys amaze me with your helpfulness and knowledge. I'm gonna go with grease cups with the lithium cup grease. Makes perfect sense.

BTW, I'm gonna drive a blackhawk rotary vane pump with a Nelson 1 3/4 that will supply the water motor and make it spin........the opposite end of the water motor shaft will be v-belted to some sort of whirligig for the kids to watch.

Cool enough?

 

[CharlieBiler]

I'm not saying that somebody didn't change them before I got them but both my oil field engines came with oilers on crank bearings and zerk or greaser on rod bearing. Unless I'm mistaken these both will be turning at same speed. Should I change one or the other. Have the one running and it seemed to work ok, but I'm new to this ! Also why not motor oil in these bearings? Jim

Sorry, but I just got this.
Auto engine oil has a detergent that washes out and keeps skungies, sludge, and carbon from building up in crankcases. Type SB oil has about triple the 'slipperiness' of engine oil. Take a screwdriver and dip it iengine oil. Now pinch it between your thumb and pointing finger, and pull on it. Repeat the test with crankcase oil. Everyone sees the difference immediately. Auto engines were once destroyed by the buildup of deposits. It is a classic tradeoff.

 

[TomFrampton]

Do you still have this water motor?