Engine Bearing Grease

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Engine Bearing Grease

Postby Bailey » Sun Feb 13, 2022 3:59 pm

Hi
I am getting everything together to assemble my 55st engine and I am wondering what kind of grease is recommended for the engine bearings.My engine has the grease nipple to grease the bearings but I am going to pack them before assembly.
Thanks
Bailey
 
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Re: Engine Bearing Grease

Postby Mutt » Sun Feb 13, 2022 4:22 pm

dint use the grease fittings. It was a fad that didnt last long (about 5 years) the bearings will get plenty of oil from the gas mix.
Mutt
 
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Re: Engine Bearing Grease

Postby Bailey » Sun Feb 13, 2022 5:26 pm

Does that mean that the bearings shouldn't be packed with grease before assembly?
Bailey
 
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Re: Engine Bearing Grease

Postby pumpguy » Sun Feb 13, 2022 8:13 pm

I can remember one instance back in the day where a 165 got its crankcase flooded with pre-mix fuel and in the process of kicking it over to clear it out, the pre-mix came squirting out of the grease nipples.

Of course that means if fuel can come out, air can get in which is something that should not happen.

Lesson: Make sure those grease nipples are sealed off in one way or another so there is no chance of air leaking in.
pumpguy
 

Re: Engine Bearing Grease

Postby pumpguy » Sun Feb 13, 2022 8:17 pm

Bailey wrote:Does that mean that the bearings shouldn't be packed with grease before assembly?


Certainly wouldn't hurt, but the pre-mix fuel will wash the grease out anyway. If you do add grease to the bearings, pay attention to the formulation. Some greases have additives that could cause problems.

Have no first hand experience with this; just say'n.
pumpguy
 

Re: Engine Bearing Grease

Postby Bailey » Sun Feb 13, 2022 8:51 pm

Thanks for the input. I had put a grease gun to it to make sure it was clear but now that I found out I don't need to grease it it raises another question, is it sealed off to air. The nipple doesn't have a hex head so I don't know if it is pressed in of if its threaded.any ideas?
Thanks
Bailey
 
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Joined: Sun Dec 12, 2021 12:13 am

Re: Engine Bearing Grease

Postby Mutt » Sun Feb 13, 2022 10:33 pm

crank it up and spray some soapy water on them. If the bubble, they leak.
Mutt
 
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Re: Engine Bearing Grease

Postby pumpguy » Mon Feb 14, 2022 12:44 pm

Do some online research on PRESSURE TESTING 2 STROKE ENGINES. This is also frequently described as LEAK DOWN TESTING.

While I must admit I've never done this, this is the surest way to learn how pressure tight and how free from air leaks your engine is.
pumpguy
 

Re: Engine Bearing Grease

Postby Bailey » Mon Feb 14, 2022 2:49 pm

Hi
A friend of mine does a vacuum test on his engines. He plugs the carb inlet and exhaust out and draws a small vacuum with a hand pump. If it holds that will tell you if is all sealed up good.
Bailey
 
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Re: Engine Bearing Grease

Postby Mutt » Mon Feb 14, 2022 3:28 pm

I have done this, even spent some time to build a rester. Dont let it fool ya. I was pulling my hair out one day when I rebuilt a motor and it would not fire. I did a pressure test and the new left seal leaked pretty good. I tore the whole new motor down, installed another new seal. Still leaked, but not as bad. Shaft was in excellent condition, no pitting or grooving. So then I dedided to try and start it anyway. It fired right up and runs like a champ and it still blows bubbles.
I got to thimking about the shaft and seal. The seal that is very commonly used and has been for the last 30 years is an INCH seal.Foor an 11/16" (.688") shaft, but the shaft diameter is 17mm (smaller. 669") SO I looked near and far and finally found some metric seals with the same o.d. and thickness, but for a 17mm shaft !!! They work perfectly.
Test this: get a new common 6816 sprocket seal and a new shaft (or even a good used shaft). Slide teh seal on. It has little to no resistance. Then get the correct seal for the gen/mag shaft and slide it over the sprocket shaft You have to force it on, because it's gonna seal. So happy I found some 17mm seals !!!!
Mutt
 
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