Mabel is sick I think

Well YIPPEE today was the first time I could play with Mabel (my '48 8N) I changed the oil this morning and I decided to run some 15W40. To my surprise there wasn't even an oil filter in the canister :shock:. I got her all back together and decided I would pull the 4ft box blade for a while. She did good for about 15 minutes then all of a sudden she started skipping (sounded like I lost a cylinder) and wouldn't pull the box blade. So I parked her back under the shed and pulled the plug wires off one by one while running. #3 didn't change the tone of the motor, and #4 barely did. All 4 had spark to the plugs. Hmm, so I pulled out my compression tester and here are the results. Engine at operating temp. #1-105psi, #2-100psi, #3- just a tick over 75psi, #4-80 psi. I put all the plugs back in and fired it up, 10 psi oil pressure at idle and just 20 psi with throttle bumped to half way. She has 30 psi when cold, which is understandable, but I guess the real tell tale is when they are up to temp. I guess when buying an 8N don't run out and get all excited (like me) because she's pretty. Pretty sells, running good, doesn't. On another note though, the hydraulics are rock solid, no issues whatsoever. Will hold the HD box blade up for longer than I wanted to stand there and wait with the engine off. So I guess, Ole Mable is going to get a fresh engine. Heck she probably deserves it.

I think I'd just soak the rings in 3 & 4. That's a bit cheaper than an engine rebuild.
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deerslayer303,Did the #3 plug have oil on it and fouled out.Is is smoking bad.It could have some stuck rings on #3 and #4 so don't jump into to a rebuild just yet.You could try a ATF or Marvel soak on the rings for a week and see if that helps,or even a couple anti foulers on #3 and #4 and it might run a long time for you.So many N's get tore down for a rebuild that don't really need it no more than they get used.That's why the rings stick on some of them from setting unused.

(quoted from post at 14:37:13 04/29/17) deerslayer303,Did the #3 plug have oil on it and fouled out.Is is smoking bad.It could have some stuck rings on #3 and #4 so don't jump into to a rebuild just yet.You could try a ATF or Marvel soak on the rings for a week and see if that helps,or even a couple anti foulers on #3 and #4 and it might run a long time for you.So many N's get tore down for a rebuild that don't really need it no more than they get used.That's why the rings stick on some of them from setting unused.

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I did notice a little smoke while pulling the box blade, but I mean very little. The plugs are dark on 3 and 4 not really oil soaked. I will put some Marvel on 3 and 4 when she's cooled off good amd let it sit till next weekend. That low oil pressure has me worried though.

You need to tell us what the oil pressure is
when it's at idle and at 3/4 throttle after
its at operating temperature.
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Two adjacent cylinders being low often means a head gasket leak between the two. While the compression on the other two is not great, it is OK. As already said, try unsticking rings first, if not successful, most likely just a head gasket will make her able to do whatever you want from her for the next twenty years.

Deerslayer,You should have used some 20w50 oil in it /next time! Castrol GTX 20w50 is all I use in the south summer and winter.

I'll check the oil psi at a little higher throttle setting. Today I got 10 at idle and 20 at about half throttle.

Hot?

It has to be hot to mean anything.
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I would put tranny fluid (seems I always have extra around here) into three and four and, as said, let it sit for a couple of weeks. Whirl the engine over without the plugs in it to remove most of the ATF. Put the plugs in and work it until it gets to operating temperature, then take it back to the shed, put a gauge on it and then check the oil pressure idling at curb idle. When you have your oil pressure reading, shut it off and take the plugs out of 3 and 4 and retest.

(quoted from post at 03:36:26 04/30/17) Hot?

It has to be hot to mean anything.
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Yeah, it was at operating temp.

Well I let it sit for a week with MMO in the cylinders. I removed the plugs and blew out all the oil. Then reinstalled the plugs and cranked it up to burn all the mystery oil out. I shut it down and pulled a compression test with WOT this time I got 90, 90, 90, 75. Reinstalled the plugs amd fired it up and let it run for 20 minutes it never stopped smoking. And it was blowing oil out the exhaust pipe, alot of oil.