Farm Equipment - 3750 cracked block fix?

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3750 cracked block fix?

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=44046
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Topic: 3750 cracked block fix?

Posted By: DarrylinWA
Subject: 3750 cracked block fix?
Date Posted: 18 Jan 2012 at 7:45pm

I am looking at this 7080 maroon belly tractor. Good tires and sheet metal. Torque limiter needs repaired. Anyways, the salesman said that there is a crack that weeps water when the engine is warm. It is about 3 inches long max It is right above the injuection pump almost right on the edge of the round. It looks like next to the main water passage way on the engine. (KevininWA) said this.

Question, What would it take to fix this. I know the right way is tear down the engine and fix and reassemble. Tractor is not worth that.

Is there anything out there to use and v out and fix. The guy tried a gray JB weld and did not work.

My gut says to pass on this and keep searching.

Any thought good and bad or if someone knows of a good way to fix this with a material out there.

Thanks in advanced, Darryl

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B 10 Custom. Serial # 1001 D21, First D21 built 69 #4498 and Last D 21 Built #4609. 1946 MM UTU. And 2000, 2005 Pete's. AC custom Hauling.

Replies:

Posted By: jnicol6600
Date Posted: 18 Jan 2012 at 7:55pm

This seems to work for some people but I have no experience with it myself.

http://www.locknstitch.com/

Posted By: DrAllis
Date Posted: 18 Jan 2012 at 8:26pm

I had a 220 like that years ago. I took a flat plate (3/16" if I remember right) larger than the cracked area and drilled and tapped holes into the block with 1/4" Gr8 bolts (1 inch apart) and then cleaned off the block area with a grinder and got it as flat as possible and used Black Max RTV and bolted the plate right to the block with much RTV squeezing out from under the carefully fitted plate. I even had to attach the plate at the bottom with four or five bolts, then heat the plate red hot and form it around the shape of the block to get the fit just right. Injection pump was removed. I spent a few hrs doing this, but it looked good and never leaked and was way better than any in-chassis welding could ever be, as the bolts and plate tied the crack/block together.

Posted By: DrAllis
Date Posted: 18 Jan 2012 at 8:27pm

More I think about it, the plate was 1/8" thick.

Posted By: Unit3
Date Posted: 18 Jan 2012 at 9:53pm

I have been wondering about the stuff on TV, Flex Seal. They claim it is rubber in a can. I have a plate behind the starter on my 7080. It seems like the engine blowby in coming up and into the cab.

Posted By: Amos
Date Posted: 18 Jan 2012 at 10:42pm

I had a 170 that had water in it in the winter sitting at a dealer, I bought it and then found the crack behind the starter. It had a new water pump on it when I bought it,should have told me something...anyway the crack was drilled , starting at the ends working towards the center with 3/32 tap sized drill and trapped with set screws put in. Each hole drilled so as to be as close to the one next to it and drilled into it in some cases,put locktite on each set screw and then when you meet the center weld over top all of them with a nickle welding rod. Never had trouble with the crack for about 3500 hrs after before the tractor left mt place to a different dealer many years after this. Bot sure what it cost as the dealer paid for the repair, but it took and afternoon.

Posted By: skipwelte
Date Posted: 19 Jan 2012 at 10:12am

Ive done the method that Amos has, with the overlapping setscrews. Worked real good, although we didnt weld over the top. Each set screw was overlapped with the one next to it and we started at one end and ended at the other end. Each set screw was loctited in and RTV was used to hide the set screws then painted over. Good luck.

Posted By: Clay
Date Posted: 19 Jan 2012 at 11:24am

Contact your Belzona distributor or consultant. They have a product called Super Metal (1111). It WORKS!!!!!!!!!!! Not surprised the JB Weld failed. I have used Belzona Super Metal since the mid 80's and have fixed numerous engines and other castings.
You will also need to lock down and stabilize the crack. Locknstich, overlaping setscrews and the plate method work great.
Wish you were closer, I would be happy teach you how to do this repair.
http://www.belzona.com" rel="nofollow - http://www.belzona.com

Posted By: bakwoodsfarm
Date Posted: 19 Jan 2012 at 5:55pm

Just weld it. Take a stick welder with nickel rod and weld about a half-inch then stop, leave it for about an hour or so and weld another half-inch. I have fixed a lot of cracked blocks this way, the trick is to not let it get to hot. If the metal gets red hot then you can forget it, it will just crack beside the weld as it cools. I know there are 4 Olivers, 7 A/C's, 2 John Deeres, and 15+ boats out there that I have welded and none have come back with leaks yet. If you want it to look real nice when your done, just put some jb weld over your weld when your done.

Posted By: darrel in ND
Date Posted: 19 Jan 2012 at 10:20pm

I'd go along with the belzona idea; I've had good success with it. Darrel