# Catastrophic error



## TonsOfGuns (May 10, 2020)

Hi guys,
I have a 1989 Ford 1920 tractor with an N844 diesel motor. I have the motor out and was preparing it for dropping it back in when I noticed one of the freeze plugs was seeping coolant.. After a few hours of fighting the freeze plug I decided to drill a hole in it thinking there would be air space behind it, and indicator of when to stop. There wasn't, zero air space between the plug and the cylinder wall. I bored in .15 inches before I stopped. The bores are 0.35 inches thick. Question is did I just ruin my block? I doubt the strongest JB weld can fix this one. What do you guys think? 

I could drill out the bores and sleeve the motor. Would probably be cheaper to buy another short block...


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## harry16 (Dec 8, 2011)

Can a welder get to it?? Weld it?


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## TonsOfGuns (May 10, 2020)

I'm under the impression welding cast iron is pretty risky and leaves cracks which will compromise the cylinder wall even more


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## Bob Driver (Nov 1, 2017)

So you drilled .15 deep into (but not through) the .35 thick inner cast iron block wall (42%)....

Am I correct in assuming that inner wall separates a water jacket passage from the crankcase oil cavity?

Would you assume the design engineer built some sort of safety margin into his calculations when he spec'd the block wall thicknesses for thermal expansion, stress pressures, etc.?

Now consider the actual stress pressures on both sides of that cast iron inner block wall.....

Crankcase pressure would be what, near zero on the backside of the wall? Water pump pressure on the front side of the wall at that freeze plug opening can't be much, otherwise that plug would be way more than just "seeping". Is that freeze plug thicker than .20? That's the minimum thickness (with safety margin) the engineer calculated the outer water jacket wall needed be to keep from failing under the water pump pressure, at one of the points he considered must susceptible to a freezing failure (he didn't just randomly pick that spot for the freeze plug opening).

OK.... Now consider

1) What exactly is it you're worried about, under a worse case scenario, for a "catastrophic failure" of your boo-boo?
2) What are the odds of failure?
3) What are you willing to spend to give you the comfort level to not worry about what is essentially a .15 "dent" in a .35 thick cast iron plate...


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## TonsOfGuns (May 10, 2020)

Hi Bob, 
Thanks for that reply. I was wondering about the water jacket wall as well. Consequently have another block that threw a rod to look at, and I don't see a water jacket (like I'd expect from working on cars). It looks as if I drilled directly into the cylinder wall. I'll attach a picture of the other block, and a picture of the damage I did to the new block


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## Bob Driver (Nov 1, 2017)

So if that's not a water jacket opening, what exactly was dripping for the "freeze plug"? Is it a "sleeved engine" with liners, or an automotive type block? 

I've pulled liners out of diesel engines that had "cavitation pits" way deeper that that were running with no problem at 1,000,000 miles.


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## TonsOfGuns (May 10, 2020)

Its definitely a water jacket, but in this block the block wall (where the freeze plugs are) is around the cylinder bore. There is no channel that I can see around the cylinder wall apart from the space between the cylinder wall and the side of the block. I see cylinder wall/coolant space/blockwall. What I drilled into was the cylinder wall. At least that's what I see when looking. I do not see a liner unfortunately. Had it been lined it would be less of a concern.


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## TonsOfGuns (May 10, 2020)

I just confirmed what I said above by drilling into the original blown block. What I drilled into was the cylinder wall, it measured .28 inches thick. There is no liner


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## Bob Driver (Nov 1, 2017)

I'd run it... If you start puffing white smoke out the exhaust stack, I may have been wrong. 

If you do start seeing white smoke, pull the radiator cap and hook a radiator pressure tester up. If the needle "flutters" as it's running.... Feel free to say the SOB was definitely wrong


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## TonsOfGuns (May 10, 2020)

The cylinder wall isn't punctured. I just took a bit of meat out of it. So it will run and seal fine for a while. It will probably develop a fracture there over time, and as you said will start puffing white smoke. Either way I appreciate your insight and input. Thanks Bob


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## Bob Driver (Nov 1, 2017)

After 50+ years as mechanic, you learn to categorize certain questionable situations...
1) Minor FU -- Run it and hope for the best
2) Major FU -- Run it and hope nobody notices/remembers you did it


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## TonsOfGuns (May 10, 2020)

And always look back and say to yourself "God damn that was dumb why didn't I..." 

Thanks


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## Bob Driver (Nov 1, 2017)

Been there... Said those exact words 1,000's of times


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## Hoodoo Valley (Nov 14, 2006)

TonsOfGuns said:


> And always look back and say to yourself "God damn that was dumb why didn't I..."
> 
> Thanks


Yeah huh. II honestly thought I was the only one that said that!

I'm with Bob. About the only thing to do is run it. I'd be leery as hell putting weld type heat to the cylinder for fear of distorting that machined surface on the inside of the cylinder bore.


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## TonsOfGuns (May 10, 2020)

Thinking more about this, that freeze plug was bashed in so far in it was touching the cylinder wall. No wonder it failed. Think about how hot that sucker must have gotten...


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## Hoodoo Valley (Nov 14, 2006)

Fairly low on the cylinder though isn't it?


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## TonsOfGuns (May 10, 2020)

About 1/2 way up. Its 40mm plug. Lots of surface area


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## Hoodoo Valley (Nov 14, 2006)

What I meant is that isn't the plug close to the bottom of the Piston stroke on the cylinder where there'd be less heat, as opposed to the top portion of the cylinder?


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## TonsOfGuns (May 10, 2020)

It's mid way


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## TonsOfGuns (May 10, 2020)

JB weld makes an extreme heat cold weld epoxy. I'll give it a shot 

https://www.acehardware.com/departm...Vnx6tBh07DwBqEAQYASABEgLeivD_BwE&gclsrc=aw.ds


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## Bob Driver (Nov 1, 2017)

What the hell.. you've got nothing to lose at this point. Can't honestly say I believe it will actually make any difference whatsoever toward rectifying any potential problem, but if it works as a "chill pill" for your mind, go for it.

The biggest issue I would have to overcome with using the JB Weld is it's only going to take a 1/4 of a thimble. Then every time I would see the rest of the unused JB Weld tubes laying around the shop, it would piss me off and I'd start worrying about the problem again .


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## TonsOfGuns (May 10, 2020)

I definitely could use a chill pill. I'm restoring this tractor and 2 weeks into it everything has gone well. Grinding rust is a ton of work. If the N844 block was not so hard to find it wouldn't be such a big deal. They made a 2.2L N844L and a N844T turbo version of the same engine. Playing out my options if this doesn't work I wonder if either varient would bolt up to my clutch housing and frame.


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## JLSteiner (Aug 6, 2017)

https://dieselcranks.com/shibaura-s...-broken-spot-on-back-of-block-4-cyl-dies.html
Chip out of what looks like dowel pin hole


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## TonsOfGuns (May 10, 2020)

Availability: Out of stock

I saw that listing. Thanks though


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## McCray Don (Apr 9, 2020)

TonsOfGuns said:


> Hi guys,
> I have a 1989 Ford 1920 tractor with an N844 diesel motor. I have the motor out and was preparing it for dropping it back in when I noticed one of the freeze plugs was seeping coolant.. After a few hours of fighting the freeze plug I decided to drill a hole in it thinking there would be air space behind it, and indicator of when to stop. There wasn't, zero air space between the plug and the cylinder wall. I bored in .15 inches before I stopped. The bores are 0.35 inches thick. Question is did I just ruin my block? I doubt the strongest JB weld can fix this one. What do you guys think?
> 
> I could drill out the bores and sleeve the motor. Would probably be cheaper to buy another short block...


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## McCray Don (Apr 9, 2020)

Devcon is a very good metal type filler.
I think filling in the divot with J.B.Weld or Devcon would be beneficial for piece of mind and a little more strength to the wall .

I totally agree that it will be fine .


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## McCray Don (Apr 9, 2020)

McCray Don said:


> Devcon is a very good metal type filler.
> I think filling in the divot with J.B.Weld or Devcon would be beneficial for piece of mind and a little more strength to the wall .
> 
> I totally agree that it will be fine .


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## Dan of all Trades (Jun 2, 2018)

Half way down, the water side of an cast iron cylinder wall. Diesels don’t have much of a stroke like a gasser. Don’t weld it! Even if you could, the cylinder wall will distort from the weld pulling... So outside the box, looking in. Where does your piston fire rings ride, compared to your drilled whoops? If the top piston ring passes over the, well CRAP! Now what?! Me personally, I would be concerned, but I would fall asleep anyway. If it ain’t in the fire ring path, build it and run it. If it IS in the fire ring path, build it and run it! It WON’T blow out the cylinder wall. If it we’re at or close to the block deck, where all the magic happens... with tremendous force, then it may have a shorter life. I say clean that frost plug hole up, pop a new plug in with some sticky stuff and carry on! If you tried to put any kind of JB weld, super glue, 20 minute epoxy, whatever it will pop out during the first heat cycle. And then that bit of hard crapola goes... where? Water Pump, radiator, thermostat? Not worth your time or $$. 
Step one, smack drill hand. Step two, don’t drill frost plugs. Step three, tell your grandkids, true story! -and enjoy life!


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## TonsOfGuns (May 10, 2020)

Interesting I've got advice to not plug it with JB weld, and advice to plug it with JB weld.

The divet is half way down the cylinder, relatively pretty far from TDC. It should theoretically be under coolant


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## Dan of all Trades (Jun 2, 2018)

JB Weld Is a two part epoxy resin puddy that you knead to mix. Mix a dash and put it in your oven at the lowest temp, say 225°F?. Thermostats open between 160-195°F depending on OEM for Cooling. So cylinder wall would be a tiny bit hotter, right? Epoxy doesn’t smell good at any hot temperature. That Awful smell, my friend, is the epoxy breaking down. Never heard anyone use JB weld to fix a hole in a piston or a cylinder wall for that matter.


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## ttiiggy (Apr 14, 2020)

Tap it and JB Weld in a set screw. 
That will really mess with anybody that takes it apart. )


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## TonsOfGuns (May 10, 2020)

I'm planning on using this: http://knowhow.napaonline.com/how-to-use-jb-weld-extremeheat/


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## willy81 (Jan 30, 2020)

why not go to a wood stove shop and get some cast iron cement and it works on 454 exhaust
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## Rodgerm (Aug 28, 2019)

I am with Bob run it, there is a lot of other stuff that will go wrong before what you did creates a problem. Since it appears mid way in the stroke there would not be that much pressure in the cylinder, I just turned 65 and still trying to learn when just to leave things the hell alone. This is one of those situations.


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## DanielCT230 (Apr 17, 2018)

there is nothing to worry about at all except future corrosion of the "hole" into the bore itself after about 500 years of running without any corrosion inhibitor in your coolant. if you are really concerned then best solution is to make up a copper dowel (then soften it by annealing) and punch and peen it into place with high strength loctite. $5 solution and you can sleep easy till the day you die....


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