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repairing an engine block

mattyt1984

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Jun 5, 2011
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336
Location
New York
I have an engine that froze and leaks coolant out of block I have 2 rows of hair line cracks about 4 inches long. What is best way to repair. Weld braze solder JB weld. I have run engine and does not leak into oil and runs as it should I just need to seal up the external leak.
 

Ronsii

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Jun 26, 2011
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Western Washington
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s/e Heavy equipment operator
We talking small engine like lawnmower of something like a D8 cat? if its a thin aluminum type block I would go with JBweld or the low temp aluminum weld sticks... if you're talking cast iron block then I have seen regular brazing work... they also have a drill tap plug system that appears to work good.. I think it's called stitch lock or something like that...
 

check

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Apr 1, 2012
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in the mail
. they also have a drill tap plug system that appears to work good.. I think it's called stitch lock or something like that...
They use that inside combustion chambers. The head on my Ford tractor is done that way and works fine. I think it would be too much (overkill) work to do that for a simple external water jacket crack that never has more than 20 PSI on it.
 

funwithfuel

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Mar 7, 2017
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Will county Illinois
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Mechanic
They use it on Cummins "53" blocks with common coolant passage cracks. Cummins also recommends this procedure for deck repair iirc. If it will survive external and deck surface, it will work. But, BUT! It has to be done properly.
 

td25c

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Feb 14, 2009
Messages
5,250
Location
indiana
Then there's the " Drill , Tap & patch " system .

Have seen it done on water jackets on the outside of the block .

Drill & tap for studs and drop some rubber gasket material between the block & patch plate .

Ran into something similar on an 8-V-71 block repair . We just had to deal with crankcase oil on that round . Connecting rod decided it needed more room to swing .

LOL ! :DBlair's pictures 367[1].JPG Blair's pictures 369[1].JPG

And back to the race track . :)
 

Ronsii

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Yeah td25c!!!, Have done a few similar things myself :) where there's a will there's a way.


And of course there are always the emergency/get it working repairs... might not be permanent or last long but whatever it takes to get the job done ;)
flexseal.jpg
 

Truck Shop

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Dec 7, 2015
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WWW.
Find the starts and stops of the cracks using a torch on low flame. Drill the ends of the crack and install a solid 1/8" pin with sealer. Then add KD block sealer
to cooling system. The early Power Strokes had a problem with stress cracks at left and right rear of blocks caused by as Ford tells it {head bolt stress}.
I repaired two that way, both with a little over 100K at the time. Both ran over 250K died in a scrap yard and never had any problems with leaks.
 

Ronsii

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Jun 26, 2011
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3,464
Location
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s/e Heavy equipment operator
Then there's the " Drill , Tap & patch " system .

Have seen it done on water jackets on the outside of the block .

Drill & tap for studs and drop some rubber gasket material between the block & patch plate .

Ran into something similar on an 8-V-71 block repair . We just had to deal with crankcase oil on that round . Connecting rod decided it needed more room to swing .

LOL ! :DView attachment 197146 View attachment 197147

And back to the race track . :)
I was under a friends house a couple weeks ago fixing a pressure leak.. with a similar procedure... cut a piece of rubber bungee strap then pop a hose clamp around it and done!!!

before:traci-pipeleak.jpg
After:traci-pipeleak-fix.jpg
 

td25c

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Joined
Feb 14, 2009
Messages
5,250
Location
indiana
I was under a friends house a couple weeks ago fixing a pressure leak.. with a similar procedure... cut a piece of rubber bungee strap then pop a hose clamp around it and done!!!

before:View attachment 197153
After:View attachment 197154

I like it ! :cool:

Reminds me of a saying an old truck driver tolled me years ago …..

" There's what you want to do and what you can do at the time ".

Focus on the " Can Do " with readily material's first .

Hey , sometimes you have to throw the book out the window and do what ya gotta do . :)

And keep a stiff upper lip Bro !

 

DMiller

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Feb 21, 2010
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Hermann, Missouri
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Cheap "old" Geezer
A slight caution with expectation. Engine block in my donor tractor had a hair line freeze crack, the previous owner sealed the Outer crack was Not aware it had also cracked inward. Chased phantoms of water in oil and oil in water pulling head, oil cooler, and dismissed the repaired block. As I tore it down to dispose of the junk the water jacket had also cracked a oil gallery in the expansion process, was not ever going to eliminate that problem without a block change.
 

Old Doug

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Oct 16, 2013
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Mo
We talking small engine like lawnmower of something like a D8 cat?
I started working at a place one fall and they had a guy check the antfreze in every thing he missed a D8 that they had worked on that summer i dont know what had happen to it but it had new heads and i found out later it had a bent rod. It cracked every wear even the pony motor. We pulled the heads and sent them off i spent alot of my winter mig welding crackes then i heated the weld and rubed a stick of some thing over it that melted and got hard. It worked i presser tested it and we ran it some but they took it out on a job and a rod went throw the block. I found out they had straitend the rod and it did work.
Mild steel ER70S-6 Mig wire.
 
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