Crack in block

[coakes00]

I need your gentlemen's opinions.

After buying it with a broken head bolt, having the screw extractor break off, then after getting that out have the tap snap off, I finally got the hole by the exhaust port cleared out. I know it looks a little rough around the hole but the threads from a 1/4 inch down are good. And I plan on putting head bolt sealant on when I reassemble it.

I started to clean all the grease and dirt off the block and noticed what looks to be an old crack on the fin. It barely goes into the block (see attached picture). Does this mean I need to scrap another block or it with still work to overhaul? Its a K241 that is .020 over and will only be used for mowing in a 100. Any insight is greatly appreciated.

[J-Mech]

You really need to clean it better so we can see, but it looks to me like it goes all the way to the valve seat. We're you going to overhaul it?? At .020" over already, it may or may not need more than another .010" to get a good bore. I'd say I'd junk it. That's really close to the valve.

[coakes00]

Originally Posted by J-Mech

You really need to clean it better so we can see, but it looks to me like it goes all the way to the valve seat. We're you going to overhaul it?? At .020" over already, it may or may not need more than another .010" to get a good bore. I'd say I'd junk it. That's really close to the valve.

This wasn't the original motor I was planning on overhauling. I didn't even know it was .020 over until I got it home and took the head off. When I bought it for $75 I was told it had a broken head bolt and smoked a little. I originally had a K301 that after tearing it apart, had a bad crank and needed a lot of machining so on my budget was out of the question. I'm a high school science teacher funding this my self and using it to teach a class. The school no longer has a shop program so I'm trying to incorporate some vocational aspects into a general science class for seniors. The K301 smoked bad so I figured it would be a good educational opportunity to teach my students. If this motor is too far gone too, I'm probably just going to scrap the whole idea a keep with regular classroom stuff from now on.

[Merk]

It looks like the block has a crack (possibly 2?) . The crack looks to end close to the valve seat.
Can it be fix?????? It can be fix if you know someone who knows how to weld cast iron. To do it right you need to take a grinder and grind a groove in it. Them the block needs to be warmed to a certain temp before the block is welded. After the welding is done the block needs cool down to room temp the same way the block was heated.

I had a Kohler block that the machine shop was supposed to check for cracks before they do any machine work to it. Needless to say they forgot that operation. The was found when they shaved the block. My Son was working with a machine shop that had the capability to repair cast iron blocks for racing and pulling engines.

He said he would weld the block for $20. To me it was worth the gamble.

Here is picture after the block was welded:


After machine work was done to block:



The engine is in a puller that pulls in the stock class. It seems to run ok. It has 3-4 pulls on it and the tractor was park because remodeling a house is more important. This is my Son's puller.

The block would have been scrap if the crack was found before machine work was done. There are plenty of 10-12 horse short block assemblies that can be purchase for a few $$$$. Maybe you find a bare 12 horse block for a few $$$
The carb for a 12 and 10 horse are the same.

[stimpy]

you should poor man crack check it , wash the area off with a chlorinated brake cleaner to Clean out any grease in any cracks then spray carb cleaner on it wipe quickly and dust it with baby powder and see where it sticks the crack will show up nice or buy a spot check kit ( penetrant test ) and you have another item that we use in the shop to show them , the crack can be superficial and last for many years , but if it goes to the seat scrap it or build it and run it till it pops , I have seen worse run for a long time atleast your not running into a water jacket .. ,

you do not want to spend the money to grind, weld and machine it when a new block would be cheaper .

[guido]

Originally Posted by coakes00

The school no longer has a shop program so I'm trying to incorporate some vocational aspects into a general science class for seniors.

I'll risk getting flamed on this...
It irks me to no end that school districts drop vocational classes, but will continue to fund athletic programs.

Have you had the block magnafluxed?

[coakes00]

Originally Posted by guido

Have you had the block magnafluxed?

No it hasn't. Just found the crack today and don't want to spend more on it if its not worth it.



Took some emery cloth to it and got some more pictures.

[Merk]

Originally Posted by guido

I'll risk getting flamed on this...
It irks me to no end that school districts drop vocational classes, but will continue to fund athletic programs.

Have you had the block magnafluxed?

My school system is the same way.......school board just spent $500000 on a new athletic building. Sad thing is the school sucks in sports.

[john hall]

What would scare me is what if you do nothing, put it together, and the crack continues to move--right toward the valve seat causing it to come loose. The right shop/welder can fix that crack and probably guarantee it. We had a 4 cylinder Massey Ferguson tractor block welded between the sleeves and re-machined for the sleeves--and the shop guaranteed the repair, cost wasn't that bad either. Trouble is finding a shop that will put their money where their mouth is. If it were me, I would see if I could find another block/engine since a replacement can probably be acquired for what a repair would cost