8N exhaust leak

I know this has been discussed before. My 8N motor rebuilt with new manifold the 70's. It is leaking around the back #4 cylinder. before I pull the manifold, I'm wondering what the are best gaskets available? Any with additional material that will better seal the surface. As I remember the block surface was OK 40 years age. Tractor only gets light use. There was some discussion about sealing or filling pits in the block surface?? JB weld?

If the block is badly pitted, (usually around # 4) you will have problems; get out the hi-temp metal epoxy. (Not JB Weld) VersaChem's exhaust manifold repair, or ThermoSteel, is said to be good to 2000 degrees. Clean the area real well with brake cleaner, put a little epoxy on it, put some wax paper over it and bolt down the manifold. After it dries take off the manifold and take a die grinder and clean the epoxy that might squish into the port. Look at the manifold, again around # 4. If it?s pitted & burned, it isn?t going to seal. Time to surface it or get a new one. Do not double the gaskets! The gasket has two pieces, left & right (or front & back.....whatever) Use hi-temp Permatex or even Copper coat. Make sure the surface is squeaky clean!
75 Tips

There is a high-temp epoxy that I have used in a situation like you have. I don't remember the name on the stuff though. It is sold in a clear plastic tube about 6" long. The epoxy stick in that tube is about 11/16" in diameter and made of epoxy resin and hardener. One compound on the inside and the other rapped around that. You tear what you need of the stick and kneed the two parts together. Then pack it around the leak. It won't stick to the manifold and head while you're putting it in place, but it will once it hardens. Press it into place as best you can and walk away from it. The next day it will be as hard as the cast manifold and your leak will be fixed. I wish I could remember the name of the stuff.

This must be what I used. I see JB Weld makes some like it too.

http://www.ebay.com/itm/Permatex-84...07&hash=item4409257d75:g:j4kAAOSw74NZjXFq

I spent 37 years in manufacturing, the heavy duty truck, auto, and machine tool industry, starting as a basic machinist working up to mfg. engineer when I retired. One thing I learned was based on the Dr. Demming philosophy of 'Do It Right The First Time'. I've been working on these old N's since I was 8. As with any project, I learned that a band-aid fix job is just that. Don't expect it last to long and be a cure-all. Pulling the manifold is not that difficult, it is just time consuming because of all that has to be done with the carb, air cleaner, draining coolant, and surface prep, etc. Sometimes we have to do what we have to do in an emergency, but to me, since the task involves a lot of time and work, I'd just as soon do it right the first time, get a new manifold, gaskets, hardware, and be done with it. There's always the unexpected problems that arise as well. For example, often, if the carb has not been removed in a long time, the rubber hose connector to the air cleaner becomes hard, old, and brittle and is stuck to the carb inlet port and the air cleaner tube that takes additional time to remove and if it is bad shape, will need to be replaced with a new one too -another unforeseen added expense. Just my opinion... so your mileage may vary...

[i:654c4848f0][b:654c4848f0]<font size="4">Tim *PloughNman* Daley(MI)</font>[/b:654c4848f0][/i:654c4848f0]<table width="100" border="1" cellpadding="0" cellspacing="0" bordercolor="#000000"><tr><td height="25" colspan="2" bgcolor="#CC0000"></td></tr><tr><td> </td><td></td></tr></table>

I'll 2nd Bruce - that process worked for me and like you I'm light use - mowing maybe 30+ hr/year . .. and also what Tim says . . . lots of little extras that can/will take time. My mission creep was the vertical exhaust refitting! Search the forum for all previous posts - past knowledge/experiences are very useful.

When it is the exhaust manifold that is pitted or worn away, I take the exhaust manifold and on a flat surface I sand it down until I have a flat surface over the entire manifold surface where the gasket fits.

If it is on the block that is a different subject.