8N--LOUD VIBRATION

[Clem]

I have a loud vibrating noise coming from the front of my 8n. It usually occurs when I am messing with choke or accelerating. I have not yet changed the oil and it probably needs one could this be the problem?

[Bigdog]

Perhaps a water pump bearing or maybe generator bearing?

[Clem]

Bigdog- I seem to have been picking your brain a lot. Can it be the fan out of balance? If so how do I know and fix it? I haven't ruled out burned valves/pistons, but have ruled out loose hood attach bolts. how do you test the bearings as you suggested?

[Bigdog]

Wiggle the fan, look for end play in the shafts. Loosen / remove the belts and turn the shaft. Feel for roughness as the shaft turns. You should fee no noise, looseness or grittiness as the bearing turns and there should be virtually no end play in the shafts. And definitely no side play in any of the shafts.
If you're careful you can use the poor man's engine stethoscope (long screwdriver) to help pinpoint the noise. Just be careful around moving belts, shafts and pulleys.

An out of balance fan could be a source but if the fan is truly out of balance, there will likely be some obvious play in the fan shaft from excess wear.

[DuxburyFarmall]

Bigdog,

an you explain

poor man's engine stethoscope (long screwdriver)

to me? Is it just placing it against an object and see if it vibrates?

Thank you,
Chad

[Bigdog]

Place the tip of the screwdriver at the point where you think the noise is originating. Then place your ear to the end of the screwdriver handle (direct contact). The closer you get to the source of the noise, the louder the sound will be. That's why I say be extra careful. You don't want anything to slip and end up on a moving surface. It'll ruin your day if you have to pick screwdriver out of your cranial cavity.

[DuxburyFarmall]

Ah I see now. Yes that would hurt!.

Thank you for the answer.

Chad

[Brent]

Clem,

Do you have a front end loader on it? If so check the drive shaft to the hydraulic pump. The spline on the end of mine became worn which caused a bad vibration until I replaced it.

[Clem]

I started up the 8n yesterday and ran it for awhile then drove it. It only vibrates when I accelerate beyond the 1/2 way mark on my accelerator. It doesn't seem to do it in 4th gear. I checked the fan and pulleys as suggested, they seemed okay. I have not check the bearings yet. Brent-- I do not ahve a loader on it. Also, BigDog-- it has an alternator but I'll check the waterpump bearing.

['Country' Elliott]

Hey Clem...Is your 8N using oil? If so, it sounds like it might be a main bearing with too much slop gone bad on the crankshaft.

[Clem]

I don't think I am using oil, but to be honest I haven't looked into too much since the cub engine has been seized.

[Clem]

The loud vibration was the gas tank vibrating off the hood.