'41 9n No Compression, What to do?

RobBruno

Member
I posted a while back that I had picked up a non-running '41 9N that had no compression. I checked with a compression gauge both dry and wet and very light compression. I pulled the valve cover and manifold to check the valves. When I spin the motor over a very slight puff is heard from the exhaust valves so it has a very tiny bit of compression. I compressed air into the each spark plug and don't hear any coming from the valves so I think they are seating ok. I pulled the head and don't see any major issues with cylinders. Meaning I didn't see any cracks or anything like that. I have soak the rings for days and multiple times and didn't get any change in the compression. When I took the head off, I put MM oil in each cylinder and covered the entire piston. Within 15mins, it had all drained through the cylinder.

So my dilemma is if I want to tear the motor down and rebuild. I got a couple implements with the tractor and have sold one which basically covered what I paid for the tractor. The other implements I use on a regular basis. I figure I am at ground zero as far as investment in this tractor. Were I am in MD, a 9n/8n can go from a conservative $1000 to a high side of $1500. There are exceptions of course, but that is the general amount. I figure I will spend an easy 300 to maybe 500 on the rebuild of the motor. I can do most of it myself and worked at a machine shop to get through college and a while after so I have some help in that regard as well.

I am trying to decide if I should just part this tractor out and if I did, could I get 800 in parts which is what I figured I would net if I invested in the motor and sold the tractor as a running tractor. This tractor was very well maintained before I got it. The PO had maintenance receipts for years. The sheet metal is in excellent shape (way better then my 8N) and the tires and rims are also excellent. It has replacement loop rims that have no signs of rust. The PO told me the hydraulics worked fine although I have not been able to test them myself. He was honest about everything else, so I have no reason to believe that the hydraulics do not work. Everything on this tractor looks to be in great shape except the compression.

What are your thoughts on how much the tires rims, sheet metal etc would be worth for this tractor? Part of me doesn't want to part it out because I will still be left with something to take to the scrap yard. But like many here, I am trying to balance my time and work to invest in a tractor that I am ultimately planning to sell anyway. I don't need a second N tractor. If I could get close to what I would net for the tractor if I fixed it, I would strongly consider parting it out. Just not sure of the value of some of the parts to people.
 
I can not understand why people always pull
the heads off of these things.
Now you have no way to test it.
Remember: an engine Can Not run itself into
a zero compression situation. Not possible.
You have open valves.
Have you spun it over and watched to see if
the valves are moving? It only takes a
little bit of valve opening to lose all
compression. Flood the valve stems with
MMO. Get them moving so you Know they are
seating. Then put the head back on and test
it again.
If you go down the rebuild/tires/paint
route you will quickly have the equivalent
$ as you would if you buy a decent
600,800,2000,3000 or 4000 - any of which
will have WAY more features and options
than an N.
 
Rob, you asked what we thought. My opinion is, if you don't really want the tractor, put the head back on and sell it "as is". Steve sent a link showing how to test the hydraulics, so You can do that. There's probably someone out there looking for a project like that.
 
Ultradog, yes, I watched the valves and they were all moving. They would bottom out on the lifter. Now, I understand that just cause they bottom out on the lifter, that doesn't mean they are sealing. I will try the test from the links that were posted. I pulled the head because I could see the valves moving with the valve cover removed. I really was expecting something catastrophic the cylinders.

I wouldn't need to invest in tires, paint, etc because other then the motor, this tractor is in great shape. Doesn't need anything except getting the motor running.

I will also try the trick from Kirk on youtube for checking the hydraulics.

Meanwhile, if anyone is interested in a project let me know.
 
if it were mine and since you have the head off I would just buy a set of rings, complete gasket set (setis almost as cheap as a head and pan gasket ) and install them and go to a straight 30 weight oil. feel your cylinder walls. if there good and smooth then just clean them but do not hone them. you can buy the parts from ebay for less than 100 bucks. that's what I did. parting a tractor out means you will have a lot of parts laying around. some things will sell but a lot wont. by the way did you do a compression test on each cylinder before you removed the head.
 
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