1941 9N Head

[Bman0612]

Hello All, I am new to this forum. Hoping I can gather some of your collective wisdom on a 1941 Ford 9n that I took off a guys lawn recently. Hadn’t run in 10 years, previous owner replaced the spark plugs annd rebuilt carb and the plugs fouled inside 4 hours according to him. I started going through this unit but something that was initially alarming was that I got coolant plus some oil out of the radiator when I drained it. My initial suspicion is that the oil rings on the pistons is shot and that I should rebuild the top end. To be clear, I have never done this before on a 9N. I am hoping you can look at the photos and help with the below questions:

1. Why do 2 of the spark plugs have inserts and look raised compared to the other 2?
2. The head gasket looks like it’s a firm rubber with metallic rim around the pistons…never seen this before. All the rebuild kits I see have a form of paper so curious if anyone has seen this previously.
3. The valves on the ends look more worn than the others. Normal?
4. I have a variety of cleaning tools, any recommendations on best cleaner to go through this unit especially with the knowledge that oil got in the coolant lines?
5. Do you see anything in the photos that should be a question that I didn’t list (observations welcome)? Some studs came out with nut when opening is why you don’t see them all.

 

[Non-farmer]

1. The inserts are a bandaid intended to help prevent fouling.

Edit: sorry, I see you're new so welcome to YT lol was the first thing I read and promptly forgot it. My memory is not improving with age.

 

[Sean in PA]

If the oil rings are shot, then oil would be getting in to the cylinders, but I don't see how that could get oil into the radiator. The valves that look burnt appear to have the valves stuck open slightly, not closing all of the way.

 

[Hobo,NC]

Hello All, I am new to this forum. Hoping I can gather some of your collective wisdom on a 1941 Ford 9n that I took off a guys lawn recently. Hadn’t run in 10 years, previous owner replaced the spark plugs annd rebuilt carb and the plugs fouled inside 4 hours according to him. I started going through this unit but something that was initially alarming was that I got coolant plus some oil out of the radiator when I drained it. My initial suspicion is that the oil rings on the pistons is shot and that I should rebuild the top end. To be clear, I have never done this before on a 9N. I am hoping you can look at the photos and help with the below questions:

1. Why do 2 of the spark plugs have inserts and look raised compared to the other 2?
2. The head gasket looks like it’s a firm rubber with metallic rim around the pistons…never seen this before. All the rebuild kits I see have a form of paper so curious if anyone has seen this previously.
3. The valves on the ends look more worn than the others. Normal?
4. I have a variety of cleaning tools, any recommendations on best cleaner to go through this unit especially with the knowledge that oil got in the coolant lines?
5. Do you see anything in the photos that should be a question that I didn’t list (observations welcome)? Some studs came out with nut when opening is why you don’t see them all. View attachment 124294View attachment 124295View attachment 124296View attachment 124297

Its common on a worn out tired Flathead,,, Years of heat cycles and combustion pressure bypasses the head gasket... You can re-torque but the fix is to re-place... re-torque is only a short term patch...

Pre-test,, you could have pressurized the cooling system but at low pressure the head gasket would hold,,, the next test that would have told the story would to have pressurized the cylinders at 100 PSI... I do this to prove to myself its a head gasket issue then Re-torque to confirm then re-place so I can sleep well at night (I am a overpaid wrench but earn my keep in the real world)... As much as i disapprove of folks jumping the gun and replacing a head gasket in the dark,,, head gaskets on a Flathead don't last forever... Every time I have seen this issue the engine really needed to be rebuilt cuzz the rings and cylinders were worn out enough to let excessive oil into the combustion chamber,,, that's were the nasty sticky black gooey crud came from in yer coolant...

 

[SkipperII]

The two that extend outward were sold as temporary cure for oil fouling sparkplugs.

 

[Eman85]

You've leaped before you looked and you are about to go on an adventure. I don't know what you're attempting to fix unless you are going to remove and completely rebuild the engine.

 

[Bman0612]

You've leaped before you looked and you are about to go on an adventure. I don't know what you're attempting to fix unless you are going to remove and completely rebuild the engine.

She is getting new pistons and valves and gaskets but I am curious what your approach would have been? Sounds like a different opinion on what the problem is or could be?

 

[Eman85]

Pistons means sleeves and bearings and possibly oil pump which means align bore and of course splitting and then a clutch and transmission out put shaft seal and on and on and we never diagnosed how oil got in the radiator or why the plug anti foulers.

 

[Bman0612]

Pistons means sleeves and bearings and possibly oil pump which means align bore and of course splitting and then a clutch and transmission out put shaft seal and on and on and we never diagnosed how oil got in the radiator or why the plug anti foulers.

What if I changed out pistons without splitting it? I was thinking I would use an overhead hoist to support the weight while I drop the oil pan using a motorcycle lift and then once that was removed insert jacks in the front to additionally lightly support that weight so the 5 remaining bolts in the back don’t take too much pressure. I don’t own an engine stand so getting creative in approach.

As a learning side note for me: customer states new plugs fouled in 4 hours even with two crutch inserts to prevent it and you find oil in the radiator coolant. Where would you have started or assumed the issue was?

 

[Jim L WA]

I would think there are at least two problem areas. One, the rings are letting oil into the combustion chambers. Two, the head gasket probably failed and let that oil get into the water.
You have no idea about the bottom end. Was there good oil pressure when it ran?
Like Non Farmer said, welcome to the forum. Just a side note, but the forum just below this one is for the N tractors like yours.

 

[Bman0612]

Appreciate the welcomes Jim and Non-Farmer! I think this is going to be a very good forum (even better when I get questions into the right one). Most of the comments agree with most of the fixes I will apply, probably less so on the how but sometimes all we can do is improvise when we aren’t made of money.

Will continue to post questions as they come up!

 

[Non-farmer]

No need for a hoist to do an in-frame rebuild. Main thing is to support the trans. I didn't touch my crank or oil pump because my oil pressure was fine - what is the pressure in this one? I just put in new sleeves, pistons (edit: and rings of course), and rod bearings. I have a hoist, but not in my machine shed - it's in my garage. I didn't use it, and I don't have an engine stand either.

 

[Eman85]

Did the tractor overheat at all when used? Oil pressure? Have you drained the oil and if so how was it?

 

[Bman0612]

Did the tractor overheat at all when used? Oil pressure? Have you drained the oil and if so how was it?

I bought it from an old farmer who let it sit for over 10 years so not able to answer most of those questions. He said he rebuilt the carb and put new plugs in and they fouled inside 4 hours which led him to park it and buy a replacement. The oil is drained and to my eye it looks like standard 10w30 or so (no metal filings/water/etc). The metal filter around the drain plug was slightly more thick/sludge like but not terrible. Know more when I drop the oil pan next weekend. Having sat as long as she did, a lot of parts needed replacing so I just jumped right into it.