There is a crack in the block between cyl 2 and 3 - closer to 2 - of my rebuilt motor.
There were numerous recommendations to try a block sealer -Alumina seal, etc. - so I went to Autozone.
Boy was I surprised at the choices - good old Alumina seal was there for $2.99 and there were others that went as high as $20.

One even said that it was perfect for Nano cracks.
At first I was excited because this had to be Mork and Mindy's secret brew. Nano-Nano!
When I read the label it said that it was specially formulated for nano cracks i.e. small cracks.
Since I have a big crack - my motor has a big crack - I decided to stay with the cheep stuff.

I am driving with the valve cover off so I can see what's happening and have the return holes blocked.
I have driven about 15 miles and it hasn't stopped leaking yet.
I'll give it a bit more time tomorrow but don't think it will be enough.

I checked the oil and it so far it looks as if the head gasket is OK,

GUYS THANK YOU THANK YOU for telling me to look at the block before doing the head gasket again. Nano Nano!!

Almost forgot - During the first 5 mile drive the started to sputter and then stopped running.

Like dead! No go!

Yep I had Steve's problem - Fuel Starvation - But in my case it ran out of gas!

Thank God for cell phones. 20 minutes later my wife showed up laughing with gasoline and off I went.
In between I met some people in the sub division - I wish the car had been running so I could off them a ride.
I even got to tell one couple who my son is working for, but i won't mention the name at this time because I don't want to turn this into political discussion.

Fred the stuff that I have used I bought at Walmart and it cost about 8 dollars for a 16 oz bottle , I put the whole bottle in. I usually drain the radiator and fill with water before putting the sealer in then I drive it around it may take several drives to get it sealing you may even add another bottle but once it's sealed drain half the water and fill back above the baffles with the coolant of your choice. I really hope this works for you. PS, have a full take of gas before you drive off.

JB weld.

I had the same problem. Here's how I fixed it several years ago with JB Weld. It is still fine today.

Link:
http://www.mtfca.com/discus/messages/257047/270852.html

Mark beat me to it. Devcon what you can see. Chemiweld what you can't.

I had a crack in my Model A block that I couldn't get to with the stitch screws. I flushed the block several times with water, unhooked the radiator, and hooked up an air hose with a regulator and pressure gauge that could read under 10psi. Then using a mixture of water glass and water, plugged the top outlet, started the engine and ran the air pressure up to about 7psi. As the engine warmed up the crack sizzled and leaked and finally stopped leaking. I stopped the engine, but left the air pressure on. Letting the air pressure off would have lowered the boiling point of the water and caused the mixture to turn to steam and expand very quickly. Be careful not to let the engine run too long and get too hot, just enough to get the crack to expand enough to open so the water glass can get in and seal. After cooling down I cleaned the area with a small grinding wheel, you need really clean bare metal, and used JB weld to cover. Today you cannot find any trace of the repair.

This is a no-brainer, but always run a newly repoured/repaired engine with plain water until you are satisfied it has no leaks. Don't assume all is well and dump in the 50-50 mix from the get-go. It's pretty tough to clean antifreeze out completely so that repairs can be made. As in most cases, I had to learn the hard way.

I forgot to add be sure to flush all traces of the water glass out before adding antifreeze. Water glass and antifreeze mixed together makes a really nice hard jello like compound. I disconnected the radiator before doing the repair because I didn't know if it could take the pressure and didn't want to take the chance of having the water glass plugging it.

I have a small crack in my 26 engine in the #4 valve galley, I use a JB weld product called Perm-O- Seal it has worked well for years, it is organic and can be used over and over, when you drain the system just pour it back in and the leaks stop in just a few minutes. The part number is Ds114, the phone number for JB Weld information is1-800-529-3530 if you have any questions, it says it can be used on large cracks.

Rick

Think I found the latest leak. It is just inside the flange where the cover attaches. The guy that sold me the motor missed spreading JB weld in that area, but did not miss the valve springs.

I cleaned the area and spread a bit more JB. Now my fingers are crossed hopping that this will allow me to drive the T a bit before winter.

I contacted the guy that sold me the motor and he offered to exchange it for another. Since the one I have has new aluminum pistons, SS valves, Kevlar bands etc I asked what was in the one he was offering but he hasn't replied.

I still am not happy with the sloppy JB weld work or block finish that might be causing another leak but need to find a reasonable solution. Pictures of the JB weld are in the I think I need to remove my motor thread.

I think you need to talk to the seller. Sounds like he will stand behind his work. Is it practical see him face to face and check out his other engine?

Ted you are right.
Unfortunately I have limited time to do a face to face but hope he will do the right thing

I am still trying to figure out that the second motor is ok and has the same upgrades because I ultimately want to sell it when/if I get the original one rebuilt.

Call me old fashioned but I value my integrity as most of the T guys do and don't want to pass on a problem
I make mistakes but will not take advantage of any one on purpose.

My wife teaches ethics at a local college and I fully subscribe to doing the ethical thing.
In her first class of each semester she talks about not wanting to hear anyone using the f word.
They are supposed the think instead of feel.

Also I am very happy that my 40 year old son gets it because he has been hired by a prominent presidential candidate, but that is way off topic and I don't want to get my post booted again
.

It is happening.
Nothing worked to stop the leak so I am pulling the motor.
The guy that sold it to me is willing to swap it for another.

It should take a lot less time to change because I know where the bolts and nuts are.

I hope I can get it done before the season in New England ends and we can do the traditional Thanksgiving ride.

Fred,

I kinda thought this would be the case. That's a bad area to have a crack. My buddy had the same trouble. He was lucky to find a good block with std. bores & mains with good original babbitt. We reused all his engine parts, (added new rings), and had a really nice running motor. Good that your engine guy stands by his work. Too bad he tried to slip through this "repair" however.

Hope it all works out o.k. for you.