Cracked Block :-(

gt4play

Member
Well, I decided to actually have a go at the infamous JB Weld approach. I've read a number of success stories with this stuff - if I can get this to last me through the summer, all the better!

Oh, and btw, there's more than one crack in the vicinity. Despite my good intentions, it certainly appears I did a crap job at making sure my car had the proper coolant mixture when it sat for a while.. :(

Pulled basically everything I could in the front to minimize the amount of swearing and acrobatics to get the job done
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You can see the one crack at the top of the freeze plug cavity - it extends further up about halfway to the mating surface. The other, longer crack is off to the left, kinda horizontal...you can see the dark line from moisture seeping through.
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My attempt at tracing the crack and 'starter' holes to prevent the crack from spreading
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A rough surface is recommended for proper adhesion. In addition to this, I went at this with 120grit sandpaper (not pictured). Rough enough?
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JB Weld applied. I placed a thin piece of clear plastic over the freeze plug area to keep this stuff from oozing south. I'll go in there with the dremel and clean it up a bit so I can at least get that piece removed. Considering this entire area is pretty stress-free, I'm optimistic this approach will work, at least through the summer. Anybody wanna start placing bets? ;)
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Mafix

New member
are we only betting on this summer? or until next summer.
this summer, 20 bucks says it holds.
next summer, 50 bucks says it leaks.
 

WarTowels

Active member
Frightening! I think it would hold for a short time, but kinda scary either way. I love JB weld, but I don't have all that much trust in it.

Hope you find a new block soon, I never did end up finding where I thought I had seen them for sale - new.

-Towels
 

UtahSleeper

Active member
With how many alltracs have the motors swapped, I would think a matching alltrac would be the rarest of all cars lol.

I think it will hold and hope it lasts long enough for the motor to actually die from a standard bearing or piston failure, something worthy of replacing a block lol.
 

gt4play

Member
Well, so far the patched area is holding well - but only to see other leaks spring up from what appears to be behind the block. :-( I guess it's not much of a surprise if the original damage is truly attributed to freezing/expansion.

In a last ditch act of desperation, I added some of that Bars stop-leak. I know, I know...prob a bad idea. But at this point, I already knew the block was shot. My radiator is an aftermarket one that doesn't look long for this world. What's left? The head and heater core - the head can always be tanked. The heater core, well, will see if this stuff affects it much. I don't drive the car in the winter anyway - as soon as salt hits the road, the car stays indoors.

At any rate, I managed to get the car to the OC All Wheel Drive meet with a few other fellow members (literally hit the road 6 hours after I added this stuff). Despite the heat, the ol girl made it there no problems. It wasn't until I made it back to Annapolis that I ran into an overheating issue. About 1 gal of coolant had pushed out the reservoir overflow. Fortunately, it was a good stopping point for dinner anyway. And even more fortunate, after topping back off with coolant (a shout out to Eric and Willy for jumping in to help), the trac made it the rest of the way to Mt Airy without issue. :)

Not positive why I lost the coolant. Prob didn't help that I pressed my luck with my driving habits on the way back (no thanks to Willy and Eric... ;-) ). But all is well - she's safe n sound in the garage (still no leaks!). I'll likely limp along, keeping my drives local for the summer. In the meantime, I'll source a decent shortblock and have the machine shop go over it. Maybe I'll pull the head from the old MR2 GenII so I can have a full longblock on the stand before I start transferring components.

If anything, my baby is going to come out looking even cleaner than it already does. That engine bay is gonna be immaculate. :)
 

gt4play

Member
Well, after much discouragement between the two downed cars, I've finally mustered up the motivation I need to get things back on track. I sourced a full shortblock in VA for $100 over the weekend (head is still attached, seller will get it from me at a later time). It appears to be in great shape, but I'll probably still tear it down and have it tanked and inspected for good measure. It came out of a MR2 that received a Gen3 swap (engine was good before it was pulled).

Once I have a good base to work with, I'll just start transferring everything over piece by piece. Realistically, this probably won't be done until Spring. But I have the 165 to help ease the pain for a while. :D

Pless, if you're reading this, this will be a good time for me to see what you have left over for HPC coated goodies you may want to offload.

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bridge47

New member
Okay, some truth is needed in this thread.

-JB weld does not seal against pressure. Ever.
-JB weld is good for oil pans, etc where there is no pressure

When your block starts leaking again(and it will), find an old guy who has had experience welding small block chevy heads with high nickel content rod. This is a walk in the park for these guys.

Oh, and it's not 'freeze' plugs. It's core plugs. Don't count on cold temps to push them out. Not what they were designed for.
 

gt4play

Member
Some added clarification:

bridge47":3q98fdk3 said:
-JB weld does not seal against pressure. Ever.
Although logic might dictate your statement to be 100% correct, there are proven instances where it actually has worked for others - for years on end. Regardless, my little JB Weld approach was not intended to act as a permanent solution, nor did I expect it would/could serve as such. It was indeed intended to be temporary just to get me through the summer (maybe a little longer if I was lucky).

bridge47":3q98fdk3 said:
When your block starts leaking again(and it will),
It did - but not in the JB Weld patched area. The patch actually built pressure back into the coolant chambers, ultimately revealing even more fractures in the back of the block. I cannot say specifically where - at this point it didn't much matter to me anymore. I decided to take 'er off the road until I could ultimately source a replacement block, hence my latest post.

bridge47":3q98fdk3 said:
Don't count on cold temps to push them out. Not what they were designed for.
Trust me, I wouldn't have deliberately disregarded the coolant mixture thinking these plugs (even if they were truly "freeze" plugs), would cover my butt in the event of freezing. Despite how positive I was that the mixture was proper, it apparently was not. Still kicking myself for this.
 

GT4_DRED

New member
bridge47":uf27llqj said:
When your block starts leaking again(and it will), find an old guy who has had experience welding small block chevy heads with high nickel content rod. This is a walk in the park for these guys.

X2..
 

gt4play

Member
GT4_DRED":39ltjfwm said:
bridge47":39ltjfwm said:
When your block starts leaking again(and it will), find an old guy who has had experience welding small block chevy heads with high nickel content rod. This is a walk in the park for these guys.

X2..

Folks, I-bought-a-replacement-block.

After my new-found discoveries (mentioned already), there's no point in attempting anymore patchwork - regardless of how it's done.
 

bridge47

New member
Wasn't trying to kick you while you're down.

Point of my reply was to help others in the same boat.

You did the right thing by getting another block. Even welding is hit or miss depending on who's doing the job.
 

Mafix

New member
just to chime in on the new subject:
i've seen several blocks/manifolds welded. i've never seen it hold. but that's just my experience.
i've seen several aluminum things welded, never seeen an issue from the repair.

the cast welding seems to be very very hard to do. even very experienced welders turn away from it. interesting...
 

MWP

New member
After seeing the condition my block was in after having exactly the same crack, i very much doubt any type of repair (coolant additive, epoxy or brazing/welding) would hold for more than a few days.

The heat stresses in this corner of the block are huge!
When i finally pulled by block down (had been running it with the crack for ~4 months), the section that had cracked had a ~1mm lip on it. I was amazed it could deform that far.

eNpVjk2LwjAQhv9KyF2dfJqdHkWKC0JB7zLGqMGaStoFl2X_-6ZYDzun93mGeRlChz89KuSP6HnVoytxS_nWL1aUWRN9CaGNnthuL5xZSBBiBmYGS1YHysfuyRqKaWCUTmydLjEFtsrkS8FmWx_Aajv_bOqxWiM_x7blVUQoaJB78tcwsnjxcP26H997gfw5npWHHAB_me_J2MkU1XaX7uC7nEJ-V7nJPvzAqxPCXMP_kVKC1hb0hzSghAIHTi-lVUpZ4YTVYKWpfv8AULROYQ,,.jpg
 

gt4play

Member
MWP":x1eubexf said:
After seeing the condition my block was in after having exactly the same crack, i very much doubt any type of repair (coolant additive, epoxy or brazing/welding) would hold for more than a few days.

The heat stresses in this corner of the block are huge!
When i finally pulled by block down (had been running it with the crack for ~4 months), the section that had cracked had a ~1mm lip on it. I was amazed it could deform that far.

eNpVjk2LwjAQhv9KyF2dfJqdHkWKC0JB7zLGqMGaStoFl2X_-6ZYDzun93mGeRlChz89KuSP6HnVoytxS_nWL1aUWRN9CaGNnthuL5xZSBBiBmYGS1YHysfuyRqKaWCUTmydLjEFtsrkS8FmWx_Aajv_bOqxWiM_x7blVUQoaJB78tcwsnjxcP26H997gfw5npWHHAB_me_J2MkU1XaX7uC7nEJ-V7nJPvzAqxPCXMP_kVKC1hb0hzSghAIHTi-lVUpZ4YTVYKWpfv8AULROYQ,,.jpg

That's interesting. It's literally the same exact crack! Do you think yours is attributed to freezing (at some point)?
 
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