'47 Farmall M Update - Still having issues

Ken Christopherson

Well-known Member
Hello all,

Well, I haven't posted much lately.. Been busy with vacations this month, and taking care of some odds and ends around the house. Last week, I got around to doing some work on the M again. Installed new brake bands and got them adjusted(which would have been easier to do without the loader on).. But I got them done. Also wired the tractor up (at least so the charging system works, and it seems like it does). Put on 17.5 miles driving it from my friends place to my place so that it was close to the show here locally (Nowthen Threshing Show) that starts tomorrow. Seemed to run pretty well.

Now, yesterday I took it to the show grounds to start setting up our spot. Seems to me that it is not hitting on cylinder 4 again. I am getting a light 'hiss-hiss' that is most noticeable at idle/low throttle. Similar to what it was doing when it dropped the valve seat out on the exhaust valve before on number 4. I pulled the spark plug wire on 4 to see what happened.. No change in running. So, we are missing on #4, most likely due to a lack of compression I would guess. I'll know more when I go up today. Going to do a compression test, check spark, and probably pull the valve cover to see where we are at with the valve(s) seating and adjustment. Not real pleased if I am having issues with the head again, especially after what I paid to have it reworked, and 'guaranteed' for life. Enclosed is Episode 20..

Also discovered that my Lift-All is leaking pretty good. Haven't taken the inspection cover off yet, though to look around in there.
a235017.jpg

1947 Farmall M Episode 20
 
Well... Looks like the valve seat dropped out on #4 exhaust again... Already drove to the machine shop. They told me to start looking for a new head and they would do another head for me no charge (but I of course have to pay for another head)...... So, now I am in search of another head.
 
There has to be a reason the seat came out. What are they telling you. Was the head previously cracked and repaired where the seat is installed. Not enough material left in combustion chamber to install oversize seat. Have seen several fall out of different engines but replacement oversize seats, with proper interference fit should not be a problem. Keeping a seat in on a welded repair can be a problem as expansion rates are different then.
 
If you take the Pushrod off that valve, and the intake valve on #4, the seat will stay in place for the trip home. Jim
 

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