Another Cast Welding Thread

[Dustin D Ehli]

Guys, you are all going to laugh at me but, We have a D7 caterpillar at home that someone forgot to drain the water on and the block is cracked down both sides between the center two cylinders. water leaks into the oil and there probalby is about 30 plus inches of cracks. I know all the business about preheating and cooling slowly but that is practically impossible with this gigantic engine block.
Would i be the biggest idiot on planet earth to attempt a repair on this or am i barking at a stump hoping for an apple to fall???

I was considering brazing instead of welding and i figured i have nothing to lose (save for the welding rods) because as it sits, it is junk.

[George Andreasen]

Before hauling out the torch, why not just use a little JB Weld first? Clean the cracks out first and force the JB in. Add some sealer after the JB sets up. Thermal expansion might cause a few leaks, but it might also hold without problems. It's sure worth a try before other methods and as you said, right now it's junk until repaired. In any case, good luck!

[Dustin D Ehli]

Thought of that George but this engine has spit heads and the cracks in the block are right where the heads are seperated down both sides of the block, as it sits i don't think there is much structural stability left in the block.
I don't know if you know these tractors but the engine is held up from the bellhousing only, the entire engine and the radiator and all related front equipment are mounted to the engine and there are no frame rails as on the D8. the engine is bolted to the transmission with the bellhousing and that is all that holds the entire thing on. Plus if it were started now who knows if the block would not just crack the rest of the way down both sides and fall completely in half.
I know everyone is laughing now but i think it is still worth trying to fix unless i can find a block somewhere else and put all of the internal components from my engine into the good block.
PS. these engines have wet sleeves so i would be able to weld the block from the outside and the inside if i remove the sleeves
Sorry i got long winded.
Dustin

[Patrick McNallen]

I suspect that it would require a very skilled weldor and a pre-heat oven and slow cooling tank to have any hope of fixing that right, and it would doubtless be pricey. There is also a chance that the main bearing bores and maybe other critical areas are distorted or pushed out of line, too. If they are OK now, welding or brazing or running load stresses or normal operating thermal cycling may change that situation for the worse,and require machine work in addition to the welding/brazing. I have an idea that the only way to really know how badly that engine is damaged would be to remove the engine and completely strip the block assembly down to its component parts and inspect everything inside and out and check all machined surfaces for distortion. I suppose that yours is a wet sleeve engine with a detachable crankcase where the block is more like a framework than an automotive block, if so it is likely more susceptible to internal freeze damage than an integral cast block. In an automotive type block, freeze damage is *usually* limited to water jacket cracking.

[Skip Landis]

i would weld it with nirod, keeping the area next to the weld cool to the touch. weld maybe a half inch, peen the heck out of it to help relieve stress, go to the other side & do the same thing. working back & forth like that gives time for the weld to cool. if you don't get it hot, there is no expansion in the block, so less stress. you can't hurry it. it may take a day or more, but i've had good success repairing cast this way. skip in nw montana

[Dustin D Ehli]

Thanks guys, Patrick i have thought about the alighment of the camshaft and Main bearings too, i thought the worst that could happen is that it could spin a main or throw a rod and all i would be out is the time and welding rods. But then the crank would probably be ruined and putting the peices into a different block would be out of the question.
I thought that one thing on my side is that these are realitively slow running engines max rpm being 850.
If i did decide to attack such an endevour it would not be until next summer as it is getting very cold around here this time of year, wanted to work on it this summer but didn't have the time.
Thanks for all the help guys, at this point i am just researching and thinking about ideas.

PS. anyone know where there is a bare block or an engine that is shot, all i need is the block for an RD7 Caterpillar.
Thanks again for the responses guys.
Dustin

[Patrick McNallen]

You might check around on the internet for an engine core or with your local Cathouse to see if they have any suggestions or maybe they have a boneyard out back. I think there are at least a few heavy equipment "wrecking yards" around the country, and one of them might have what you need. There is probably a lot more demand for rebuildable heads, cams, water pumps and cranks & rods than for the basic block, so there may be a few of them around "ala carte".

[MoRo]

Dustin!
Hey again!
What ever happened to that surplus tractor parts joint in W.Fargo?? Drop on down to Butler Machinery and see if they know where a block might be. Just remember, your 302 definately WILL toss a rod haulin' that home in the back seat!!!
~M~

[Dustin D Ehli]

Hey Mo, Almost started banging my head on the ground from your post , yeah the old junkpile would definity throw a rod hauling a D7 engine block in the back seat, this of course would be after the transmission stared on fire and then started slipping causing me to get pissed off and overrev the engine until it blows up then i could take the 5 gallons of gas in my trunk and light it on fire and walk away.

Sorry for everyone else this got off topic, Keep the good responses and tips coming.
Dustin

[MoRo]

(To all other Stakkers; This is inside stuff!)
~M~

[george md]

Dustin,
I'm a diehard oxy/acet cast iron welder , but that is too big a casting for
most of us to work on . Two thoughts , one is the metal lok ties that are
put in across the crack and used with the threaded tapered plugs in the
crack. I have used these and they work well .
The other thought is (Diesel cast welding ) in Blaine , mn , they have the
facilities to handle the big castings . DCW bought a company that I bought
repaired cyl heads from ( North west motor welding ), NW did such a good
job that Cummins bought them , gutted the company and put it back on the
market to die . DCW bought the shop in portland ore and calls it diesel
cast west .
http://www.dieselcastwelding.com

phone # 763-780-5940

george

[Ken Majeski]

Well.... If the Block is Cracked That Bad there is Bound to be Cracks Inside the Pushrod Chambers... (And Yes... they Do crack there)... So Whadareya Going to do about that....?????

[Dustin D Ehli]

Ken, no problem there, Don't know if you know these engines but they have external pushrod tubes outside of the block. Just steel pipes with a spring holding them in place running from the camshaft offset on the block to the heads above
Dustin

[Ken Majeski]

Well... In that case you likely don't have a D7 But have a RD7. From the 7M on they had the pushrods enclosed in the block... Much more Modern Looking...

[Dustin D Ehli]

You are absolutely right Ken, it is an RD7 i should of specified this in the beginning, i did'nt even know that there was such a big difference in them.
I beleive ours was built sometime in the mid 1940's
Thanks everyone
Dustin

[Levi Gloyd]

I have had good luck repairing cast with Devcon metal filled epoxy. some of these are tough enough to thread for bolts. I buy it from McMaster-carr supply co Chicago IL telephone 630-833-0300. I once fixed a radiator for an unstyled JD B tractor that was in several pieces from freezing. I beveled the edges of the cracks with a grinder like I was going to weld it then put the epoxy on. My customer was happy you couldn't tell it had been repaired after he painted it.

[25twin]

If You're in Fargo why don't you go see Larson welding and machine?

[Andy Rafferty]

Originally Posted by Skip Landis

i would weld it with nirod, keeping the area next to the weld cool to the touch. weld maybe a half inch, peen the heck out of it to help relieve stress, go to the other side & do the same thing. working back & forth like that gives time for the weld to cool. if you don't get it hot, there is no expansion in the block, so less stress. you can't hurry it. it may take a day or more, but i've had good success repairing cast this way. skip in nw montana

This is possible. I have welded engine beds with cracks in three planes going at it this same way don't get in a hurry and walk away often to do something else this cannot get any worse unless you don't take your time. Work on far ends from each other and work slower as your welds get closer to one another. Andy

[Mat Phelps]

I've just had real good luck using Ni rod welding a small Hercules engine with a frost crack , I beveled the crack to about half the material thickness and as mentioned above weld for about 1 inch and then peen the weld till it cools to touch, If the casting starts to feel warm to the touch 2-3 inches away from the weld, have a coffee. There is also a product on the market that is a metallic polymer called BELZONA it has a compressive strength of about 12,500 psi and Flexure strength typically 8,200 psi, web site is www.belzona.com, have fun.

[half-fast]

Dustin!
I did not see any reference to the Antique Caterpillar Machinery Enthusiasts (ACME) site in this thread. (link below) You might take a look over there and get some help. Someone may be able to put you in touch with an engine block and save you a lot of trouble unless you just need the challenge. Some good people there as there is here.

Thanks Harry!

http://www.antiquecaterpillar.org/