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Discussion Starter #1
So...long story short, threw a rod in this Tecumseh about 5 months ago and didn't notice the crack and bulge along the starter side of the engine until last week.

Since the rod hadn't punched a hole through the block, I am wondering if it's possible to salvage the engine with some careful filing and drilling tiny relief bores at both ends of the crack, and applying some high-temp epoxy resin / putty like JB Weld?



 

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You should be fine with JB Weld. You have the right idea with the relief holes, just make sure before you lay the jb weld down the surface is nice and clean.

Off their website:
"My pickup threw a rod and tore a hole in the block. I plugged the hole with large washers bolted together and sealed it with J-B WELD. That was over 50,000 miles ago; still with no loss of oil. Thanks for a remarkable product!"
 

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If you got a welding shop nearby that could be welded as well.
 

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Discussion Starter #5
Well, it still needs a new set of rings, two new lifters after the rod literally lopped the heads off them, governor gear has some missing teeth, and I need to find part of the oil pump.
 

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Id gently tap it down, sand it clean, tape off a square, lay on some JB Kwik, and before it sets, remove the tape square...leaves a neat patch...Ive patched holes you could get 2, almost 3 fingers in, with JB Kwik....never leaks.

But if the lifters broke, check your lifter bosses for cracks..if they are done, scrap it.
 

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Discussion Starter #7
Id gently tap it down, sand it clean, tape off a square, lay on some JB Kwik, and before it sets, remove the tape square...leaves a neat patch...Ive patched holes you could get 2, almost 3 fingers in, with JB Kwik....never leaks.
Is the JB Kwik just as strong as JB Weld that cures overnight?

But if the lifters broke, check your lifter bosses for cracks..if they are done, scrap it.
Didn't think of that, but I'll check. I did notice the lifter stems were fully intact, but the 'heads' were damaged. One was ripped clean off, and the other was partially fractured, so I'd venture to guess the rod must have slammed into them at a downward force rather than directly into them.
 

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Is the JB Kwik just as strong as JB Weld that cures overnight?



Didn't think of that, but I'll check. I did notice the lifter stems were fully intact, but the 'heads' were damaged. One was ripped clean off, and the other was partially fractured, so I'd venture to guess the rod must have slammed into them at a downward force rather than directly into them.
Ive found they both tend to be the same strength after 24hours or so...JB kwik may be a shade weaker (but its a patch, not load bearing). But the setup time is much more user friendly, being able to be handled in an hour easily...vs JB regular that takes hours to setup.
 

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Got to ask. If you tap the cracked bits back, to close down the gap, I assume, do you or do you not drill at the end of the crack to create a radius that will resist further cracking? I realize this is a crack caused by impact from the backside of stuff that went BANG, so does it need to be drilled or just smack on the JB Kwik?

tom
 

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I wouldnt drill it...its got no load applied to it. If it was at the mounting foot, near a structural strengthening rib, emminating from the cylinder...Id drill.

Clean it all up nice and clean, apply a thin coat on the outside after tapping it together.
 

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Discussion Starter #11
I wouldnt drill it...its got no load applied to it. If it was at the mounting foot, near a structural strengthening rib, emminating from the cylinder...Id drill.

Clean it all up nice and clean, apply a thin coat on the outside after tapping it together.
So you'd suggest skipping the relief the holes, and just lightly tap the crack together? My only concern would be engine vibration causing the bulge to crack further.
 

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You need to check that block for distortion. I've seen alot of these that messed up the block bad enough so the starter would'nt fully mesh with the flywheel. By the picture yours doesn't look too bad, just something to check. Of course if you are using a recoil starter vs. electric this won't be an issue.
 

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So you'd suggest skipping the relief the holes, and just lightly tap the crack together? My only concern would be engine vibration causing the bulge to crack further.
It wont be a problem, just tap it shut gently, clean it all up, tape off a square around the crack that goes at least 1/2" beyond the visible ends, add JB...as it starts to set, remove the tape...and let it set it least 24hrs before messing with it.

The only way that crack will spread is if the rod breaks again and hits it.
 
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