3.0 case crack-repair ideas?

[914efi]

I managed to have total brain fade while removing broken lower head studs from my 3.0. I jammed the stud remover into the case near the chain case. Any suggestions? Epoxy, silicone or low temp aluminum solder are the most obvious possibilities. I don't want to take it apart.

Thanks-

[Scott R]

Well as Wayne's book shows most of the factory plugs are covered in JB weld, so maybe some of that would stop it up. You're going to have to get the crack very clean for it to work however.

[Bobboloo]

If it were me I would take a dremel and grind out the crack leaving a small valley for a welder to lay a bead in. Make sure the welder is an expert welder that knows how to weld aluminum.

I wouldn't use JB Weld or any epoxy because you run the risk of the crack spreading due to heat cycles and vibration from the motor especially at high revs.

JB Weld is good for filling small holes but has no real structural strength when compared to aluminum. A good weld job will restore strength and could prevent the crack from spreading.

This is a $100 weld job tops.

[cstreit]

You might also drill a hole in each end of the crack to stop any propogation. Then weld it. I definitely wouldn't try epoxy/JBweld in this area...

[914efi]

Drilling the ends is probably a good idea. JB weld and similar epoxies are hard enough that they might not move during expansion. I was thinking silicone might have the ability to move and stay sealed, but I'm concerned about the bond strength for the long term.

Thanks

[mppickett]

I'm with the "weld it" group. It is a low cost but high payback fix.

[914efi]

Any opinions on welding without taking apart? Will the case remain true?

[mb911]

It will probably warp a bit but not so bad if you have someone fix it that knows what they are doing

[Scott R]

Mb's right it will probably warp. I weld aluminum on occasion, and you need to run a very fast bead on low heat to avoid that, and even then it still happens depending on the thickness of the area surrounding. But a real pro should be able to do it.

[Bobboloo]

No need to disassemble just take the whole bottom end to the welder.

I'm no welder so take what I say with a grain of salt.

I had a mag case with a crack. First I cleaned off the area as best as possible with some solvent. Then I ground out the crack and left a valley for the bead. This insures penetration and prevents the crack from spreading by removing it. Then I took it to the welder who stitched it up.
So far so good and my crack was in a more problematic place than yours.

When the welder gets ready to weld he may want to heat the case with a torch to minimize distortion before the bead is laid but like I said I'm no welder so this last step may be completely unnecessary.

[914efi]

I'm pretty sure I'm going to weld it. I'll be taking it to a good friend who is a very good welder so I'll be able to babysit it and take a bit more time. I'll grind out the crack a bit, but I don't want to create too large of an area to fill or more heat will be required. I'll post finished pics, hopefully of a successful job!

[cstreit]

I wouldn't think warpage in that area would be too consequential. Just make sure your cyinder spigot faces (where the copper gasket goes) remain straight after welding.

[Walt Fricke]

You might consider bolting the chain housing into place before welding. That might control/reduce/minimize/prevent warping in that area.

The casting is thicker by the spigot, so crossing your fingers about that may be adequate. If the spigot distorts a bit you might be able to grind high spots off so the cylinder will slide in. If the sealing surface is affected I suppose it is machine shop refacing time for all three on that side (and the other side too so you don't create a head scratcher for its next owner).

Walt Fricke

[914efi]

I had the welding done yesterday. I thought about attaching the chain case, but it limits access and the gasket would minimixe heat transfer anyway. The reason I decided to weld rather than risk one of the cooler aluminum solder techniques is that with the TIG, I felt the heat would be much more localized. This was definitely true, the case was cool to the touch only 2" away from the weld.

There was a bit of build up on the cyl seat, but I can clean that up easily. It looks like it was a succesful weld, time will tell once the engine goes back in service. I can't say how much it cost since my friend would not take any money!

[Walt Fricke]

Good to have friends!

Does the cylinder slip nicely back into its spigot? TIG was certainly the thing to do - now you have strength, an oil seal, and (one hopes) avoided distortion.

I suggested bolting the chain housing on (without a gasket) so it might serve to prevent warping. I once had a mag case half welded where an escaped rod had damaged a spigot and then some. Some years later I took the case to a shop for line boring and the needed spigot machining. The crusty machinist (they all seem somewhat that way to me) shook his head and muttered when I said the welder only had the one case half, so no, it hadn't occured to me to have the halves bolted together during the welding. He hoped this hadn't warped the case, etc. But apparently it hadn't.

The docs have a nifty term for where you are and I have been more than I care to remember: iatrogenic injury.

Cheers

Walt

[914efi]

Walt, Your suggestion was a good one. I have not yet tried fitting the cylinder back in, but I will measure the spigot to be sure. I have just about finished the smoothing of that face, but I wanted to wait until I was fresher before I gave it the final touch. I had some heat sink compound on the ID during welding to minimize any issues, and the alumimum transfers heat so quickly that I don't think it will be an issue. Most of the heat can move right into the bearing web from this point. We did not grind the crack out since I was not concerned about strength and I didn't want junk getting into the engine. The thread in the stud hole is fine.

Iatrogenic means dumbass?

[Walt Fricke]

"Iatrogenic means dumbass?"

For thee and me, precisely.

For the docs it just means injury during attempts to treat, which isn't always due to neglect or lack of skill. But a setback nonetheless. Maybe like broken exhaust studs for the likes of us?

Is the stuff that I mistook for charred red rag the heat sink compound?

Is measuring needed? Tossing a cylinder in there should tell if it slides in or binds.

Walt

[914efi]

My wife's best friend fell and broke an ankle that had just been operated on creating a real nightmare for the past year. I guess Iatrogenic applies to her. She'll like hearing that. Better than calling her a dumbass!

The red clay looking stuff is the heat compound.