Another 8N front pulley question

[Crinton]

I've read a few posts about crankshaft pulley wobble and related problems. The pulley on my 1949 8N wobbles and I have a knocking noise coming from the engine. I have the hood lifted clear and can get to the engine. After reading posts, I figured the knocking was probably associated with the pulley. Crank handle type nut on end of shaft appears tight; when tried with pry bar, pulley does not move up and down and there is no detecteble front/back motion. Pulley appears tight. Have slacked off and cleared belt and run engine briefly. Pulley wobbles (or may be bent); again, nut appears tight, no apparent pulley movement up/down or front/back, knocking more pronounced especially from front of rad and to left side of rad. This 8N has a loader and removal of front gear to get to pulley will be quite a job; have bucket off but frame for loader will have to be stripped at front before getting to actual tractor parts. Checked front housing right behind running pulley with stethoscope and running seems smooth, no knocks detected on other areas of engine either but the noise is persistent externally.

Tractor not running too smoothly; governor pretty worn; fitted new carb since old seats, etc. chewed up and engine wouldn't run right; had fitted new plugs earlier but #2 had failed, just found and replaced and engine runs better; tested spark with old plug gapped at 3/16" and spark seemed fine. Have adjusted timing a bit and have mostly got rid of hesitation on acceleration but governor could be an issue.

Any thoughts on pulley condition and knock? Know pulley removal/tightening/fixing will be a bit involved but would a bent pulley be the problem.

 

[Soundguy]

old pulley were sheet metal and would / could bend. repos are billet and won't bend. your call on that one.

as for the knock.. have you checked the fan and water pump?

 

[Crinton]

Thanks, Soundguy. This is the old style sheet metal pulley and it could well be bent. I have briefly run engine with fan belt off and no water pump/fan in loop; wobble is worse and knock is worse. Checked pulley with pry bar and no up/down or front/back movement of pulley felt or visible. Put pry bar end on tang of starting handle nut and tapped bar with hammer to see if nut would tighten - no rotation of nut, all seems good and tight.

 

[Soundguy]

probably just a bent pully. as far as the knock. is the pully rubbing?

 

[Crinton]

Is a bent pulley, of itself, a balance problem that could cause a knock? I read somewhere that a loose pulley could cause main bearing problems. Pulley is not rubbing as far as I can tell and the knock is a pretty hard sounding knock, not a rubbing. That said, I don't pick the knock up with a stethoscope on the front bearing area or anywhere else on the engine body; weird or what?

 

[Soundguy]

i doubt that sheet metal pulley being bent is throwing the engine out of ballance.

ty this. run her with no belt, kill 1 cyl at a time, then skip back to another.

IE. kill one, listen, reattach 1, then kill 2.. etc.

IE. only 1 cyl down at a time. see if the knock is tied to a particular cyl.

 

[oldpilgrim]

or it could be worn timing gears. Is it a 'puckada puckada' type knock or is it a 'hard' metallic knock? The timing gears make a puckada type knock.

 

[Crinton]

Thanks for the input. 8N battery went dead so having to recharge and also dealing with glow plug problem on B275 (maybe a new thread coming! Raining today so no progress on 8N. Soundguy, will try individual cylinder checks tomorrow. Attached videos on Youtube, not sure which link will work best (new to this stuff); if link is not hyperactive you may have to paste into explorer or chrome or whatever you use. This will give you a visual and audio on the pulley problem.


https://www.youtube.com/watch?v=xXrPhOrxPD4&feature=youtu.be

https://www.youtube.com/watch?v=ifD2r8peuq0&feature=youtu.be


http://youtu.be/ifD2r8peuq0

http://youtu.be/xXrPhOrxPD4

 

[Crinton]

Ran engine with belt off bottom pulley and removed plug leads one at a time. No change to knock.

 

[Soundguy]

hmm.. if it is a knock, then it must not be something directly related to firing chamber.

is it a metalic knock?

ever have the head off?