Got the B put together and started it...

[arlen]

Good news is it started right up and runs good
Bad news is it's leaking antifreeze from the rear of the block at the head gasket. There was a rather large "imperfection" in the casting that I was a little worried about. Right where the mold would have split. It's been there since the tractor was made, so I figured the head gasket would seal it. Kinda sucks
I plan on taking the head off of course and hoping to get some clues from looking at the head gasket exactly where its leaking. I will try and get a better quality gasket and a different gasket goop. Worse case, I will have to tear it all apart again and take the block to a machine shop I suppose.

The other problem is that it didn't build any oil pressure at all. Not sure what the deal with that is...Maybe I put the relief piston in backward???
Anyway not a good day so far

[outdoors4evr]

We'll take the good news!
Was the block / head pitted or did it have a raised imperfection? Raised might be able to be block sanded down using aluminum oxide sandpaper.
- Does the B have plugs behind the front cover like the cub? Maybe one was left out?

[Gary Dotson]

I'm glad you got it running but I'd waste no time, figuring out the oil pressure issue. You have far too much invested in this rebuild to risk it.

[arlen]

I'm glad you got it running but I'd waste no time, figuring out the oil pressure issue. You have far too much invested in this rebuild to risk it.

That's for sure! I only ran it 2-3 minutes waiting for it to come up, then I shut it down and won't run it again till I figure it out.
I'm hoping I put the piston/spring in backwards in the oil pump.
If it's not that, I'm not sure what it could be. I'm 100% certain that all 5 plugs are in the oil galleries, and all the bearings are new, and the crank is ground. The only other place I suppose is the cam journal clearance. There are no bearings to replace as the cam just rides in the block. The old timers here locally tell me that they are seldom a problem as the cam spins 1/2 the speed and doesn't have much of a load on it.

I will pull the oil pan off and take a look at the oil pump. It is moving oil somewhat at least. It did fill the oil filter, and does puke oil out of the gauge port when I spin the starter over. So it primed OK.

For the head...
I'm looking for recommendations on a brand of head gasket. The one I used was just part of the gasket kit from Yesterday's Tractors. I should have been smart enough to know that all the paper gaskets in the kit are fine, but I should have got a quality head gasket separately.
Also looking for sealant recommendations.
Of the 2 local old timers, 1 says to use aviation sealant (which I did).
The other says to use Napa yellow weather strip/gasket cement. Seems crazy, but he says he uses it even on diesels that have imperfections on the block/head.
From internet research, several coats of aluminum paint seems common.

[arlen]

We'll take the good news!
Was the block / head pitted or did it have a raised imperfection? Raised might be able to be block sanded down using aluminum oxide sandpaper.
- Does the B have plugs behind the front cover like the cub? Maybe one was left out?

It's what I would call a defect in the casting. There is a rather sharp dip right in the seem where the mold would have split. It is pronounced at the rear of the block.
I'm certain all 5 oil gallery plugs are in place.
Here is a picture of the the block after the initial disassembly. The very rear is where its leaking and you can see how there isn't allot of good gasket surface there. No pitting, just a dip. You can also see the dip between cylinder 3 and 4, but I wasn't to worried there because the sleeves protrude up to seal.
I'm wondering about troweling on some JB Weld back there at the rear, or just getting a better gasket and sealer, or the shotgun approach, and do all of the above. It started leaking about an hour after I filled it. About a drip every 5 seconds, so not a good seal at all.

[Gary Dotson]

I have no idea what brand head gasket might have been in your gasket set but Felpro is pretty much the industry leader in such things. Generally, we recommend Permatex Copper spray on sealant for head gaskets and have good success with it. The metal style gasket gets sprayed on both sides, some of the newer Felpro head gaskets are metal on one side, composition on the other, do not spray the composition side. If you have divots on your block surface that you feel are causing the leakage, a little carefully applied J B Weld may be the solution.

[arlen]

It’s definitive. Piston/spring in oil pump was in backwards. I’m pretty happy it is that instead of a bad cam bearing!
No on to the head gasket.

[Gary Dotson]

I'm happy for you as well! I've chased frustrating oil pressure problems before, had me pulling my hair out! It's a long story!

[arlen]

I have no idea what brand head gasket might have been in your gasket set but Felpro is pretty much the industry leader in such things. Generally, we recommend Permatex Copper spray on sealant for head gaskets and have good success with it. The metal style gasket gets sprayed on both sides, some of the newer Felpro head gaskets are metal on one side, composition on the other, do not spray the composition side. If you have divots on your block surface that you feel are causing the leakage, a little carefully applied J B Weld may be the solution.

Got the head removed and got all the gasket surfaces cleaned up.
Started checking the rear of the block where it was leaking.
I found that in addition to the void in the casting at the very rear, the whole area along the casting seem was about .050-.060 low around that coolant passage. I troweled in a couple layers of JB weld, and screeded it with a steel scale after removing a couple studs to get a nice flat surface. Then I used a wide flat file and got it nice and smooth, and even with the block surface.
I got a Felpro gasket coming from Napa, and I'll use the copper spray.
I'm reasonably confident that it will seal.
Here are the before and after pictures.

[Gary Dotson]

Wow, that was ugly! I sincerely hope the J.B. does the trick, your procedure in applying it sounds spot on. Obviously, decking the block would be the desirable fix but that would also involve re-cutting the steps for the sleeve register. A very expensive procedure!