A stitch in time saves nine

[Harry Babb]

I found a deal on Craigslist that was to good to be true. So naturally Chris and I had to go check it out. We found a John Deere backhoe in pretty good shape for a price much lower than comparable machines of the same size/condition.

We cranked it up and it ran just fine, all the hydraulics worked very well with no major leaks, oil was clear and even the brakes worked........so we bought it! ! !

When the South was hit with a hard freeze Chris and I was checking antifreeze in all of our "Stuff" and found that the backhoe had NONE......pure water! ! !.........it was late and we decided to simply drain it instead of going thru the antifreeze routing.

As Chris was removing the block drain he found the fly in the ointment........

Take a look



Yupp........cracked block in a water jacked just behind the injector pump

So....I read many years ago about a "Cast Iron" crack repair method that made pretty good sense to me..........What do I have to loose??

Getter all cleaned up and get started.
Notice the first 3 "Lock N Stitch" screws in the crack on the bottom of the water jacket.....



Now on to get started on the top of the crack.........drillin and tappin! ! ! !



Drill and Tap with special tap.....install special threaded inserts then grind flush



About 140 drilled and tapped holes later and walla...........success! ! ! ! !



From here the proof will be in the PUDDIN...........we will see if the ole girl will pass the test of time


The name of the product that we used is Lock N Stitch .............we used the "C" Series screws

hb

[Navatech]

That process is used extensively in marine engineering and is quite successful... However, IIRC, the drillings have to overlap each other... I also seem to remember that you have to use a few similar dohickies ACROSS the crack... Are you sure you followed the correct procedure?!...

Of course, if you had done a cooling water system pressure test (the kit is quite cheap) you would have found the crack before purchasing... I'm not saying you shouldn't have bought the thing but you could have negotiated an even better deal...

This is not meant to come over as a condescending reply but rather as a lesson to others... Harbor Freight have their cooling water system pressure test kit currently on sale for $84.99... And, you don't have to be a mechanic to use it... Attach a suitable cap to the radiator, pump up the pressure and wait a short while... If the pressure has fallen the water system has a leak... You still have to find the leak though... Look for water leakage around pumps, seals, hoses, block, radiator and so forth... If you can't find any leak it's most probably leaking into a cylinder...

[Kevin]

Harry,
I am guessing that based on what you did that cast iron can't be welded? Never messed with anything like that before and not sure where I would even start. Likely I would come here for answers!
Even though I do not have the land for a tractor, it seems as though it would be cool to have one in my inventory.
Hopefully the repair holds up.

[Navatech]

I am guessing that based on what you did that cast iron can't be welded?

Cast iron can be welded but it's a complex process wherein the object to be welded has to be heated up to something close to 2000 degrees... Otherwise the different heat expansion/contraction rate of cast steel and the welding rod's metal will cause stresses that will, sooner or later, cause the crack to reappear... In addition, due to the heat of the welding the cast iron around the weld will become very brittle so that even if the repair does hold up a new crack will occur on the interface between the regular cast iron and the brittle cast iron...

The process described was invented because while you can take the block of a truck and heat it up to do the same with the block of a ship's main engine is not viable financially...

[Bob H.]

Rust is a dead giveaway you have a crack be it in a boom or block. You sure do like to putter, my jd backhoe is a great machine can't kill it 510 B, my dad's yearly ritual is checking all the equipment for antifreeze. BH

[Harry Babb]

I am guessing that based on what you did that cast iron can't be welded?

Kevin, Cast iron can be welded but with a marginal degree of success.......and this I know from experience. I have personally welded cast iron many times with a fair degree of success.....but my personal rule is that I stay away from welding cast iron components that constantly see "Heating and Cooling" in their daily operation.

I believe in the Lock N Stitch method far more than I believe in welding when it comes to cast iron.

I also seem to remember that you have to use a few similar dohickies ACROSS the crack

The "dohickies" that you are refering to are somewhat of a "Dog Bone" shaped bar of steel that are installed perpindicular to the crack and are highly recommended when the crack has compromised the structural integerity of the casting.....which is not the case on my John Deere.

Take a look at page 4
http://www.locknstitch.com/Repair%20pdf ... 0plant.pdf

Take a look at this repair......now this is an impressive feat.

http://www.locknstitch.com/Repair%20pdf ... 20pump.pdf

hb

[bob lico]

Harry we. Had a 1967 corvette big block L-89 matching number 427" with a 4" crack in the lifter valley.engine is worth 135,000 + because it is numbered to this NCRS top flight corvette coupe so money no object in repair .block had to be repaired.we use Roll rite tap so the tap would be stronger due to no flutes in tap ( also uses a larger body drill for same thread as regular tap) breaking the tap is not a option! We made the holes a little closer together then yours any way the car is still around and repair is still perfect .like your repair subject to heating and cooling which makes this repair procedure a real winner.

[Harry Babb]

We made the holes a little closer together then yours

Bob....for the sake of not posting all 63 pictures and short video's that we took of the project it seems that my explaination is somewhat vague.

Actually the pic of the "Drilled and Tapped" holes is only the first operation. Details of the second and third op are not featured in my post but is explained in detail on the Lock N Stitch website.

The second Op is to drill and tap another set of holes in between everyother hole shown in the pic above. Then the third Op is to drill yet another set of holes in the remaining spaces between screws. When its all said and done the "Screws" overlap one another by about 25%.

The following pic shows the thread details of the "C Series" screws.....like the ones that we used. As you can see, the thread design actually adds mechanical value to the repair. Also the "Tapping Fluid" (Supplied by Lock N Stitch) is compatable with the "Sealant" (also provided by Lock N Stitch). The sealant I am pretty sure is a LocTite product

[bob lico]

We use a machinist compound similar in texture to J-B weld but sold professionally .the name eludes me at the moment but I can get it for you if you need it. We also use it to apply fine screens to oil return holes in oil galley .

[Rocky]

Beautiful Harry. Sounds a strong permanent repair better suited for heat/cool. I've done similar on a very small crack no leaks. Nice Job!

[mike ohlstein]

Nice work.

I usually just turn the radio up louder and hope it keeps running…..

[Harry Babb]

I usually just turn the radio up louder and hope it keeps running…..

Don't forget to turn your "Wiper" on too, Mike.......


hb

[Carl]

Kevin, Cast iron can be welded but with a marginal degree of success.......and this I know from experience. I have personally welded cast iron many times with a fair degree of success.....but my personal rule is that I stay away from welding cast iron components that constantly see "Heating and Cooling" in their daily operation.

I believe in the Lock N Stitch method far more than I believe in welding when it comes to cast iron.

My welder, Charlie, used to weld Cast Iron on a fairly regular basis with excellent results.

I learned from my welder one very important lesson for Cast Iron. If you cannot weld it properly, don't do it. He needed to have access to both sides, clean down to bare metal. He rejected more jobs then he agreed to take on and his cost was inhibitive for most customers further reduced the amount of Cast Iron Jobs we took on.
Cast Iron was always a process that we thought was ridiculous...the prep was twice as long as any other material he worked on. The cleaning, grinding, drilling each crack end to stop the crack from moving further...or breaking section off, V and weld all around. The heating torchs, temp sticks and welding blankets. Constantly having to go back and help him reposition...he was 75 when he closed his business and retired...we kept him busy part time till he passed at 96. He would have us order high Nickel Rods on some jobs, Monel on others and occasionally Silicon Bronze...some jobs he brought in his own filler...I never did grasp exactly why...wish I did. He would only weld using the TIG process. And the pre-heat took what seemed like forever...only to be matched by the Post heat and wrapping the part. Very rarely did we ever hear that tell tale "Ping" a sure bet we had a crack. But if we did, the process started all over again.
I learned my basics from him, never had the time to devote enough time to learning the really tricky stuff...we didn't have the time or materials to practice on either. A big mistake in retrospect...would have liked to carry forward more of his skills. But we never set out to be a welding shop and left the specialties to him.

Sorry, just recalling some found memories and paying homage to an old friend, an old friend with some amazing talent.


Any-hoo...Harry, thanks for sharing. Never heard of stitching, looks pretty interesting. Are they Buttress threads that get loaded and jammed? Will they hold parts together, if so how? ...or mostly for sealing a crack? Interesting process.

Carl

[Bruce]

Thanks Harry for the post.

[RAWicklund]

Harry, congratulations on the adoption. If you need any cylinders/rams/digging bucket I might be able to help. I have a 72' Ford 7500 backhoe that I plan on sending to the scrap yard in the next 6 months.... It was flooded for Rita and Ike and recovered like a champ.....but Issac did it in when water got on the top end.

Depending on your vintage, I know some rams will fit since I got 1 of the rams for the front end loader off of an old JD.
There yours for the taking if they will help you.

Ray

[Navatech]

Never heard of stitching, looks pretty interesting. Are they Buttress threads that get loaded and jammed? Will they hold parts together, if so how? ...or mostly for sealing a crack? Interesting process.

The process has been around for decades... I came across it during my maritime days... You can't really replace a big part in the engine room... But big parts sometimes do develop cracks... Where there's a lateral force on the crack the first step in the process is to inhibit that... This is done by one or more (depending on the length of the crack) dohickey that looks somewhat like the caricature of a dog's bone... Think of two big ends and something between... now double this so it looks something like this: -|--|---|--|-... Holes are drilled to match this pattern and the dohickey is whacked into this... This will keep the crack from opening up... The next step is to take care of the crack itself... The dohickey itself becomes part of the line of "screws"...

End result is effectively a "welding" of the crack...

[Rawleigh]

Harry: I love that process. The setup with the drills, taps and lock pins is pretty expensive though. My local machine shop has them. You should be able to make good use of them in your business. For any of you interested in welding cast Iron, lock n Stitch's website has some great info on that too and explains why it is so difficult. The beauty of the Lock n Stitch is that it can be done in sitsu without fully disassembling the engine.

Also check out the oven fusion welding these guys do.

http://www.midwestcylinderhead.com/

[Harry Babb]

Are they Buttress threads that get loaded and jammed? Will they hold parts together, if so how? ...or mostly for sealing a crack? Interesting process.

Carl....they are not a Butress Thread in that the "Topside" of the is actually at a negative angle....locking into the parent metal adding strength to the repair. Also as you can see from the pic above the top of the Insert is slightly larger than the threads. This "boss" actually fits snugly into a counterbore that is drilled just before tapping.

Lock N Stitch also has an insert that has a regular 60 deg thread...to be used when only sealing is the goal and structual integrity is not critical.

I talked to Lock N Stitch at length at a trade show in Orlando....one thing he told me was quite interesting. He said that when you tighten a bolt (60 Degree thread) the angle of the thread and the pressure of the torque actually tends to EXPAND the threaded hole slightly .... thereby distorting the surounding metal. He told me that is one reason that race engine builders bolt a torque plate to the engine block before final honing.

Lock N Stitch makes thread repair insert that has their "Special Thread" on the OD and the normal 60 Degree thread on the ID.....and he tells me that the end result is that block distortion is held to a minumum.

They have a repair for cracked Cummins heads, where they crack between the injector hole and the exhaust valve.

Pretty cool stuff......I have ran into these guys at trade shows for years but until now never really had an interest or reason to try it.......we did the entire job on our JD with cordless drills......so far I give it "Two Thumbs Up"

I talked to Greg at Lock N Stitch about our application before ordering our materials for this repair. Greg was very helpful and a pleasure to deal with

The Taps were about $45 each (we only used 1 tap for 140 holes) the C'bore about $40 or so and the inserts are $1 each.

Send me your address and I will mail you an insert to look at.

hb

[Carl]

Harry,
I went thru their site and found additional info about the process...and welding of Cast Iron. A real interesting read. I wonder how close Charlie came to their welding specs...must have been pretty close considering his reject rate.

I knew about expanding and thread distortion...once inwhile we have an ape screw a stop into the back of a 16C collet and it will not fit inside the collet chuck bore. Thread distortion I got a lesson from marina manager years ago waiting for them to fix the travel lift...45 minutes on why the Jam nut goes on first followed by the Standard nut. I love that stuff...although he went a bit long with telling me about the arguments he has had with other patrons over this...I told him why bother...most don't leave the dock anyway.

Stitching...surprised I never heard of this before your post. We never did much repair that would use...but just in working within the field I am surprised. Interference fit on the inserts or does the action take place when locking in place?
I get the sealing part...but mating parts together with the locks...I am still somewhat skeptical as to how secure the two pieces are held compared to the original state.

But the right application like yours...damn good way to repair! Portable drill, a tap, counterbore and package of inserts plus a couple hours of time...that is getting away super cheap. Not sure what else would have worked...welding would be a lost cause and most likely made it worse. Break out a package of Devcon, keep radiator cap loose and hope for the best...


If you can send, I'd love to see an insert.

Staten Island Machine Inc.
205 Chestnut Ave (rear)
Staten Island NY 10305

[Rawleigh]

Carl: did you check out the videos of the ship engine repairs? The inserts are really neat. i have one sitting in my tool box at the farm that I got from my machine shop. If you look at some of the huge repairs they have accomplished you can see how great the holding power is.