1950 Cub Clicking

[drmathieu]

Hi all!

I do not know what happened. Cub was running fine and then started clicking one day. I checked the oil and I was a little low. I topped off oil and still clicking. Any help would be appreciated.

I uploaded a video of the clicking if that would help anyone.

https://youtu.be/Gn2nZhmJR8w


Thanks in advance.

[inairam]

did you look around the fan for a stick or if the drain line is hitting the fan?

Does the pitch change with engine speed?

You can make a stethoscope out of the screwdriver buy touching a location with the tip and holding your ear to the handle end.

I would check the distributor/governor area with the stethoscope if the fan area is clear.

[coppersmythe]

first thought , it sounds a little like the fan blade hitting something . not a lot of space in there , shroud has to be tight and " just right " . coppersmythe...............................EDIT : beat by a few seconds

[tst]

that is not a happy noise, I would remove the belts 1st and run it just to make sure the noise is not coming from the fan or generator, suspect a bearing knock

[Gary Dotson]

I agree with Tim, eliminate accy's first, but it sounds like a rod bearing. Does it carry good oil pressure?

[Eugene]

https://www.youtube.com/watch?v=4wie5Y_FWL0

Above link, how to check for bad rod bearing. You can also disconnect one spark plug wire at a time with the engine running to help determine which cylinder.

Check the easy stuff first, the items the guys have suggested. Also check the ignition system for a miss or cross firing.

[SONNY]

Got the same thing in my 185 lo-boy!!! lol!! been doing that for 6 years now and still runnin! ---oil light goes out as soon as motor starts up. I assume rod bearings are shot.

[Mac AR]

Mine makes a similar sound at higher rpm. The oil pressure looks good too, between the I and L when hot. If you throttle down or put it under a load does it go away? Mine stops when you do either one so I just live with it. It runs so smoothly the rain-cap doesn't move. Even wide open its smooth. I guess if it ventilates the block one day we'll know what the problem was!

Mac

[SONNY]

The 185 only has a light---no gauge so I dont know how much pressure it actually has. The noise in mine is always there but a bit louder for a few seconds at the end of a high rev then quick idle, neighbor cant hear it but I do!-- just like the knock in my 7.3 that nobody else can hear! lol!!
I was going to try putting new bearings in it but probably easier to take motor out of the parts tractor, OR one out of one of the regular cubs and put in it.

[Glen]

Hi,
You can probably hear better what the noise is, since you are there.

If it is a knocking sound, and is lower down in the engine, it could be worn connecting rod, or crankshaft bearings, like they said above.
If that is what the noise is, it's better to repair it before running it more. Running the engine with knocking crankshaft bearings can damage the crankshaft.
Replacing the crankshaft adds more to the cost of repair.

[tst]

just put bearings in a cub the other day, after pulling down the old ones the crank was perfect, whole job only took a couple hours

[Gary Dotson]

Last one I did had to have the crank replaced.

[SONNY]

185 is a bear to get under! lol!

[drmathieu]

Thank you for all of the replies. After further investigation, I have come to the conclusion that the bearings need to be replaced. Are there any how-to videos on this?

[Glen]

Hi,
Below is the Cub and LoBoy service manual. It has lots of info. I would read the engine section, section 1, before beginning the work.
It explains about using Plastigauge to check bearing clearances.
Plastigauge is sold at auto parts stores, like NAPA.

http://farmallcub.com/rudi_cub/www.clea ... index.html

The crankshaft journals, where the bearings run on, have to be in good condition, and smooth, not grooved or rough.
Also, the crankshaft journals can get flat in places, from bearings being loose, and the knocking happening over time.
Since it has been knocking from worn bearings, you should use plastigauge in 2 positions on each journal, to see if the crankshaft is out of round, I think it explains that in the manual.

If any of them look bad, the crankshaft should be removed, and an automotive engine shop can regrind the crankshaft so all the journals are smooth, unless the crankshaft is too bad.
After regrinding, the engine would need undersize crankshaft bearings, which are made to fit the reground crankshaft.

Below are pics from TM Tractor of a Cub crankshaft, and some of the journals, in the 2nd pic.
The crankshaft is a used one, but still in ok condition.
Newly reground journals look better than the ones in the pics.