My Willys 3A and 3B Community

3A, 3B, DJ Technical Knowledge Base => "Original"-- Technical Questions, Answers, Observations => Topic started by: stony on July 18, 2018, 10:14:19 PM

Title: Lock-N-Stitch cracked block
Post by: stony on July 18, 2018, 10:14:19 PM
Hey boys and girl, time for a new what the heck is he thinking project.  So it is about time to get my 3A on the road, which means an engine rebuild.  Problem is the engine froze and cracked about 35 years ago and I figure it is about time to get it fixed.  Have done a bunch of research and it looks Like I have three options.  #1:  J B Weld and crossed fingers.  Could vee out the crack drill the ends and put on a fiberglass reinforced patch.  Cheapest and easiest but it is a good sized crack and the patch could fail at the worst possible time (anytime I am driving it).  #2:  super metal filled epoxy, either Devcon titanium or Belzona 1111.  Cost about $200 for 500 gram (1 lb) plus cloth for reinforcing.  This would be a good permanent fix but kinda ugly.  #3:  Lock-n-Stitch metal pins.  I picked this one because I have total confidence in it and once painted should be invisable.  I also liked the technical challenge.  Unfortunately by far the most expensive, about $460 for the pins and special tools needed.  The kit arrived today, so I hope to start on it tomorrow.  About 12 inches total of crack, so will take about 60 CA pins.  Photos coming.
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 18, 2018, 10:39:00 PM
This is what the crack looks like
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 18, 2018, 10:41:28 PM
I used dye crack detection kit to clearly see the crack.
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 18, 2018, 10:51:14 PM
And finally outlined where the pins need to go.  The block is about 1/4 inch thick where the repair is being made.  The curved crack was raised a bit, so I used the � double hammer method� to flatten it.  Basically you take two big hammers and lay one on its side over the raised part of the crack and wack the crap out of it with the other.  Brian fron LnS said to wack it as hard as you like and don�t worry, believe it or not it worked.  Flattened it out, not perfect but better.  If this were not the original block I might have gone with one of the new manufactured castings.  Have a feeling there is not going to be a big cost savings in the long run[ch128540].
Title: Re: Lock-N-Stitch cracked block
Post by: specialty on July 19, 2018, 03:55:50 AM
Good luck on your repair. I had a small crack or more like a imperfection on the rear of my cylinder head that would ooze coolant that i ground out and used JB Weld and its held good. Stopped the leak. Also used it on a cracked case of a 4 wheeler and its still holding today and that was a bad oil leak. Trick is to get it clean and scratched good for the stuff to get a good grip on. Your method is probably much better. Hope it does the job for you.
Title: Re: Lock-N-Stitch cracked block
Post by: athawk11 on July 19, 2018, 11:10:39 AM
I've look forward to your progress updates.

Good Luck.

Tim
Title: Re: Lock-N-Stitch cracked block
Post by: squidtone on July 19, 2018, 12:27:59 PM
Awesome detailed pictures and description. I also am looking forward to updates.
Question: when drilling for each pin, do you drill all the way through the casting into the jacket?
Title: Re: Lock-N-Stitch cracked block
Post by: specialty on July 19, 2018, 01:01:38 PM
step by step details would be great.
Title: Re: Lock-N-Stitch cracked block
Post by: 1955CJ-5 on July 19, 2018, 04:11:37 PM
I've heard about this and had it explained to me, but it sure would be great to see pictures....!

Randy
Title: Re: Lock-N-Stitch cracked block
Post by: mtnman37879 on July 19, 2018, 05:37:13 PM
https://www.youtube.com/watch?v=Pq0wfU4ZaKk
Title: Re: Lock-N-Stitch cracked block
Post by: Bob W on July 19, 2018, 06:09:19 PM
Thanks for posting this! I'm looking forward to seeing your successful results.
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 19, 2018, 06:28:24 PM
OK good news and bad news, get to the bad news later.� Drilled holes for the two major cracks, here is the upper crack with the first set of pins ground off, the second in place and the bottom holes drilled ( yeah the block is on its side).
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 19, 2018, 06:33:00 PM
Here is the bottom crack spotfaced tapped and some of the pins installed (watch the video that mtman linked to)
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 19, 2018, 07:03:03 PM
OK now for the bad news, I managed to break the teeth on the special (and very expensive) tap.  I think I may have hit a piece of hard junk in one of the holes and jammed the teeth and it broke when I backed it out.  New one should be here in a few days.  I think the key will be going very slowly and backing the tap to clean the threads often.  Just a matter of taking it really easy, should be OK.  This is as far as I have gotten, just need to tap the last of the bottom holes, then start on the last crack.  Here are the tools, spacer, spot facer and stop and tap[ch128546].  Pretty cool system, unfortunately pretty expensive too.  I must say that when it is done and painted it will be pretty much invisable.
Title: Re: Lock-N-Stitch cracked block
Post by: specialty on July 19, 2018, 09:56:28 PM
looks good. Have a question though. How does this seal the crack? Is epoxy still needed to seal from leaks and the pins for strength?
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 19, 2018, 10:14:52 PM
The pins overlap by 50%, and a high temperature thread sealant is used when you put them in.  The threads on the pin are cut so that they pull the crack together.  After they are ground off you peen them to make sure you have a good seal.  You wind up with pretty much solid metal where the crack was.
Title: Re: Lock-N-Stitch cracked block
Post by: athawk11 on July 20, 2018, 08:47:49 AM
I don't think I would want the repair to be completely invisible.  I would wear it like a badge.  Remember...chicks dig scars.   And Willys guys like seeing skilled people make difficult repairs look easy. :)
Title: Re: Lock-N-Stitch cracked block
Post by: stony on July 25, 2018, 10:46:35 AM
OK, my new tap came in last night, so I finished up this morning.  The tapered end (1/2 inch or so) of the broken tap was still in pretty good shape so I used it to make the initial thread cut.  Guessing it went about 50% depth, so made it WAY easier to do the final cut with the new tap.  All in all it went pretty well, and I am happy with the results.  Pretty expensive for the first crack repair, but the main expense is the tools.  Only used about $85 worth of pins ($1.52 ea).  So here is what it looks like, all done!
Title: Re: Lock-N-Stitch cracked block
Post by: squidtone on July 25, 2018, 12:45:12 PM
Looks excellent. Good luck on the rebuild!
Title: Re: Lock-N-Stitch cracked block
Post by: stony on August 03, 2018, 12:52:50 PM
So I knew there was a hole in the bellhousing, just did not know how bad.� Well it was not good, had a crack.� So I had a few pins left over, so why not?� The C pins are supposed to draw a crack closed, so gave it a try.� Interesting, the first hole went OK, but after tapping the pin went in real easily, so it looked like the crack was spreading when I tapped it.� Then it was pretty cool, I put the pins in one at a time, and each one was tighter than the last.� Put the last two in from the inside and they held just fine and sheared off just like they are supposed to.� I think it will be just fine.� Will patch the hole with several layers of JB Weld and fiberglass.� Here are some photos:
Title: Re: Lock-N-Stitch cracked block
Post by: athawk11 on August 03, 2018, 06:21:01 PM
Any idea why the PO cut a hole in the bell housing?� I'm trying to think why someone might do that.  Or did it break?  Hmmm. [smiley=huh.gif]
Title: Re: Lock-N-Stitch cracked block
Post by: stony on August 03, 2018, 09:58:59 PM
I have NO idea.  Looks like it was cut with a torch.  Could be that it was broken, and they cut out the cracked part.  I cleaned off the area around the hole and there did not appear to be any cracks.  I do not think it will will affect the structural integrity.  The pins should hold the crack, and I should be able to make a decent patch.
Title: Re: Lock-N-Stitch cracked block
Post by: stony on October 12, 2018, 10:34:06 PM
The engine is all done and running, so I thought it would be a good time to show the final results.� Here she is all peened and painted.� Perfect repair, does not leak a drop.  Before and after.
Title: Re: Lock-N-Stitch cracked block
Post by: MikeB on October 13, 2018, 10:49:26 AM
That is some impressive and patient  work, most people would have turned the block into a boat anchor and found a replacement. I glad It worked out and is running leak free, great work and good job in saving the block.

I have seen people cut holes in bellhousings before, some times it�s for a quick trail fix to get acces to the clutch and release arm etc when you are not in a position to pull the engine. And I�ve seen it done once when mud got sucked into the bellhousing while fording and dried overnight and had to be chiseled out the next day to make it back to the highway to be trailered home.