That "Opportunity Knocks" Engine

Russ/40

Russ/40

Well-known member
It's back, the disastrous opportunity I couldn't pass up.

Sent the block to have it cleaned and Mag'd because it looked so good on top end. Well it failed me again, but, not so bad. Attached photos of the crack found. Now from every other crack I've seen posted here, it looks like a perfect candidate for the JB Weld approach. Not being a pressurized system, and it looks to be away from being a fatal crack. What say there barners? What would you do?
 

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You could JB weld that crack, put the engine back together, and run it on a test stand to see if it still leaks. If it still leaks, then you won't be out all that much time.
 
A better approach is to clean well and sweat solder the crack full with TIN.



a local shop, Means Garage, does that with great success.
 
Have it properly welded! You'll sleep better!
 

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This crack is probably a result of the water in the engine freezing. This is not uncommon.


The first Model A engine I rebuilt back in the 1950's had a freeze crack in the same place. I had it pinned and that was considered a permanent repair. It never caused a problem.


I would think that JB Weld may be considered a temporary repair.


If you do use JB Weld, I would be sure the surface you are applying it to is CLEAN BRIGHT METAL, I would use a rotary file small grinder to prep the area.


I would not want to use anything that involved heat. This is not a high stress area, it is just the bottom of the water jacket.


JMO,


Chris W.
 
Shoot, that's why they invented BARRS STOP LEAK! Well, I do like the idea of solder, since it really is just a plumbing job anyway.
 
Sweat solder is not that difficult. Just tedious and time consuming, but very pernament. Done it twice. works great. kp
 
I'm no fan of JB weld that stuff never worked for me.

Do it right have it pinned and welded up. A good machine shop can help you.

I know of a Model A engine rebuilder that did the JB weld magic on an acquaintance's motor. Twice. Two different motors.

He had taken his GOOD block to be rebuilt, and the guy gave him a POS engine in return, his good engine was sent off to somebody else probably the guy's buddy. The motors he got back were cracked just like this one. He was furious wanted his original motor back and it was 'alledgedly' long-gone.

Makes Terry Burtz' project look better all the time, the newly mfg. blocks. Ours are pushing a hundred years old.
 
Jeff/Illinois said:
I'm no fan of JB weld that stuff never worked for me.

Do it right have it pinned and welded up. A good machine shop can help you.

I know of a Model A engine rebuilder that did the JB weld magic on an acquaintance's motor. Twice. Two different motors.

He had taken his GOOD block to be rebuilt, and the guy gave him a POS engine in return, his good engine was sent off to somebody else probably the guy's buddy. The motors he got back were cracked just like this one. He was furious wanted his original motor back and it was 'alledgedly' long-gone.

Makes Terry Burtz' project look better all the time, the newly mfg. blocks. Ours are pushing a hundred years old.
Click to expand...

I've heard of dud blocks being substituted for good ones by engine rebuilders. I insist in the same engine back again. I note the number and make sure the rebuilder knows I have the number. I also (maybe I'm being paranoid) make a mark somewhere else that I look for later. Last one was a centre punch mark filed flat again at the water inlet. No one would notice and it makes no difference to the block later.
As for that crack, I'd clean around it and give it a bit of a vee, then use RTV. RTV will remain flexible, unlike an epoxy like JB and with heating and cooling happening (hopefully) many many times, I fear JB will eventually give up - not that it couldn't be reapplied.
 
I ran an engine for many years with a crack in that same location. Never did anything to it. It just oozed a bit, but never leaked enough to drip. Lasted until I knocked the center main out by lugging the engine. The crack never caused a problem.

W. Michael
 
Of the responses, I'm mostly leaning toward soldering the crack, as whatever is done will be done by me. What soldering techniques are you suggesting? Brazing, Silver soldering or? The crack does leak when the block is filled with water. You can see the crack as a rust line. Will solder wick into the crack when rusted?
Might try stitching, as the area is so accessable.
 
Solder will not adhere to rust, and JB probably won't either. If it were a clean crack, I would definitely prefer solder over JB.
 
I am running my engine since more than 10000 mls with a JBwelded crack similar to yours. Important is to really find the ends of the crack; they ofte are nor really good visible. Clean the surface and widen the glue bed to ca. 1/8 or a bit less by grinding the surface with a dremel or so. Then in can´t go wrong.

Good luck!
 
If you are going to use JB weld something similar but better is Devcon.I used it to repair a rusted air compressor tank on my old Kellog compressor and that holds 175 psi. Been over 5years and still good.
 
You could always look for another block,talked to a guy in Hershey flea market who had a slew of motors and blocks he was getting rid of,I did not want to drive the 350 miles round trip to pick them up,maybe should have in retrospect.
 
Russ/40 said:
It's back, the disastrous opportunity I couldn't pass up.

Sent the block to have it cleaned and Mag'd because it looked so good on top end. Well it failed me again, but, not so bad. Attached photos of the crack found. Now from every other crack I've seen posted here, it looks like a perfect candidate for the JB Weld approach. Not being a pressurized system, and it looks to be away from being a fatal crack. What say there barners? What would you do?
Click to expand...

It is far from a fatal crack but one that will keep growing if not repaired properly. It's common for Model A' engines to crack in that spot.
I would also recommend pressure testing as there is a casting wire right above your crack that will also leak water as well. If you look close you see a small circle. This will leak also. To fix it permenantly, take it to Lock n stitch or someone who can do metal stitching properly.
I have provided examples of the before and after of the same crack in same location.

http://www.jandm-machine.com/metalStitching.html
 

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Beautiful work J and M!
Is the small circle visible in your photo or does one have to look at a real block with a loupe eyepiece? Is the circle the END of the casting wire and therefore very small? I am interested to know what to look for.
SAJ in NZ
 
SAJ said:
Beautiful work J and M!
Is the small circle visible in your photo or does one have to look at a real block with a loupe eyepiece? Is the circle the END of the casting wire and therefore very small? I am interested to know what to look for.
SAJ in NZ
Click to expand...

If you look at my photo in post #1, you can see it about center above the crack.
 
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