need advice on a crack in engine block

[Ncirelli]

hi im a senior in high school and in my ag mechanics class i am building a farmall cub starting completely from parts. i just finished installing all the pistons, crankshaft, camshaft, and valves, and now i found a crack in the engine block. there was a student last year working on this tractor so i assumed it was already checked for cracks and things of that nature. the crack goes through a bolt hole on the timing cover side of the block and goes down into where the gears are and also up towards the head but not very far in either direction. crack is very thin and hard to follow. im looking for advice on what should be done to fix this or if we should just get a new block and start over. i hope i posted my picture correctly, in the picture the engine is upsideown on a stand so the top of the picture is towards the oil pan and the bottom is towards the head. PLEASE HELP!!

[Bigdog]

Your picture data string is incorrect so your picture didn't post. From your description I believe you are describing the common front corner crack that occurs on many cubs. There are some work-arounds for this problem. There are several styles of re-enforcing brackets that have been designed and built by members of this forum. Welding the crack is always an option but usually ends up in a messy looking repair that is questionable at best. If this tractor is going to be a working tractor I would suggest replacing the block. Why put a lot of money into a cracked block?

[48Beacon]

I do not have the experience to answer your question on your block. If it were me and it was going to be my tractor when it was done, I would get a new block. If it is just for the grade, I would inform the instructor of your findings to show him that you have a keen eye for details and get his advice as to whether you spend the money for a new block. The reason I posted was to inform you that I was not able to see your attached photo. You may wish for the real experts on this forum to see your pic. We all love pics. When you pull up the website there is a How To button. Select it and down at the bottom there is a How to Manipulate Pictures topic.

[48Beacon]

Actually you have to select the How To button first,then go to Using the Form and then Manipulate Pic....

[Eugene]

OH, wow. There are financial considerations, no matter which method you, your instructor, and the tractor owner decide.

Attempt to patch the crack and purchase the brace, which may be the less expensive route. The brace functions well.

2nd consideration is that if you purchase another block, you could find out that it needs machine work and that your current pistons do not fit the cylinder bores.

3rd option is to purchase a running engine.

If you search this site you will find photos of the brace(s) and of the crack. The brace may make an excellent shop project.

[Stanton]

First off, welcome to the forum! Good to hear that your school has a Vo-Tech class on mechanics. Wish I had taken one at my school.

Secondly, when we speak of getting a "new" block, in reality, we mean finding a used block in good condition without cracks. There are numerous sources for this.

If this was my Cub, I would replace the block. Magnaflux or use another accepted method to verify block condition.

BTW: Whenever posting pics, use the Preview button first (next to the Submit button), if your pics are properly linked, they'll show up just as they will in the post/thread.

[John *.?-!.* cub owner]

Nicrelli, welcome to the forum. You will get all kinds of advice here, some of it may even be right. If you are having trouble posting your picture email it to me at ejpuckett@centurytel.net and I will add it to the thread for you.

[Barnyard]

there was a student last year working on this tractor so i assumed it was already checked for cracks and things of that nature.

There is a possibility the instructor already knows about the crack and is just testing you. If it is just used to test a students abilities and will be dismantled for next years class, never be used for actual work, the crack may be meaningless. Definitely inform the instructor as it may be good for extra points and take it from there.

[Ncirelli]

So my plan is to look into braces and talk with my teacher about them, the tractor is being built for the superintendent of my school he plans on only using it to plow snow. The tractor doesn't even have a pto shaft in it. It's a one time build, my teacher knows just as much about it ad I do.

[ScottyD'sdad]

I'd run the options mentioned above, by the owner, and him decide. If it were mine, I'd replace the block.
Ed

[Ncirelli]

Here's some pics of the crack.the hole bolt hole is part of the timing cover bolt holes and it is closer to the head of the engine.

[Barnyard]

Braces won't help that one. I was thinking it was the corner at first also.

[John *.?-!.* cub owner]

I see Nic got his pictures posted. He sent them to me to post, and here are the ones he sent me that I rotated to give a better perspective (they were upside down when I opened them ).




The crack is just above the governor idler gear. The braces will not help that crack any. I have never seen a crack there before, but if it were mine I would remove the idler gear and take the block to a good welding/machine shop that is used to working with cast iron and see what they say. I have one that had a crack on the rear of the block (weeping coolant) that started close to the center and went to the left and inside the oil pump. I took it to a local machinist who welded it up and milled the weld smooth under the oil pump, and I have been using it for 12 years or better. Inless that crack goes further than it appears to I think it can be satisfactorily repaired since it is not in a high stress location.

[Eugene]

Agree with John, have a professional welding shop take a look at the crack. Would be easier if the welder stopped by the school to evaluate the engine block.

Just a thought considering the crack location. Depending on technique and (rod) material used, brazing can achieve up to 70,000 psi tensile strength.

[Jim Becker]

That is a very unusual location for a crack to show up. I wonder if it was caused by freezing. I would inspect it closely to see how far the cracks go and where they stop. If they go nowhere, I would consider drilling a stop hole and maybe a stitch repair. If they stop in the water jacket, I might do nothing then add some stop leak to the coolant. If on the other hand, they go to a head bolt hole, it needs some closer inspection and a more involved fix.

You also need to closely inspect the rest of the block for freeze damage. Pay particular attention to the right side of the block in the area ahead of the oil filter. Look inside the oil filter housing as well.