Can this 3.0L case crack be welded?

jdbunda · jdbunda's Garage

Wanted to get my oil leaks fixed, and discovered it wasn't the oil line. It's around the oil line fitting for the line on the forward driver's side that goes to the tank. Wondering if this can be welded, if so if it can be done in situ, or whether disassembly will be required.

This is the bottom (facing away from the cylinders), you can see that the crack runs around the fitting:

This shows how it extends to the oil line fitting (at around 8:00 position in this photo):

And finally, as it circles around the cylinder side:

What do you think?

Flat6pac · 12:36 PM

I would say, yes.
The threaded nipple is not correct but probably used to get deep enough to reach good threads inside the crack.
That is a flow pipe, not a pressure pipe.
The picture is reversed, backwards or something..
Bruce

Dpmulvan · 06-19-2015, 12:58 PM

Same thing happened to my case however PO used jb weld. I sourced another case, yours could be tig welded no problem.

jdbunda · jdbunda's Garage

Pictures aren't reversed, but the engine is out and on a stand, so I was able to get my phone in there at weird angles/upside down to get the crack visible.

porschetub · porschetub's Garage

It would appear that this oddball fitting has bottomed out and caused this crack ??,as its an alloy case it will not be a hassle to weld but preparation is critical during the process,the case half would have to be perfectly clean and preheated before welding...a job for a true specialist IMO.
I have a friend that does this kind of work and he likes to heat treat such parts after welding to remove any stress from the process,makes sense to me but he did mention this as being more a requirement for cylinder heads however....someone may comment here

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Walt Fricke · 06-20-2015, 08:51 AM

Any oil in the crack will make a good weld iffy. If there is decent access to all the cracked parts, though, I don't suppose you can get the crack cleaner with the engine out, or apart. Draining the oil and using brake cleaner and air probably going to work as well as they can with the case apart.

However, close inside from this is a rubber seal for the oil pump sump discharge. Will this withstand the heat generated by welding in situ?

SoyRacer · SoyRacer's Garage

Tig welding generates concentrated heat (enough to bring alloy to a molten state) and the surrounding area must be free of oils/contaminants. The case must be split and if the material is not brought up to temperature first you may warp the case half. I'd plan on having the case planed and line bored. Also, don't forget that the threads will need to be tapped, oil pressure plunger port will need to be ported to spec and the oil return tube port may need to be re-shaped. There's a lot going on there.

Rufian · 06-20-2015, 10:54 AM

Yes, it can be fixed, no biggie!!!, cheers.

mreid · 06-20-2015, 11:10 AM

I think you have a good chance of seeing that piece break free when you remove that fitting that caused the problem to begin with. Either way, if the engine is apart, it can be effectively welded.

fred cook · fred cook's Garage

Over the years, I have found that some of the best, most talented welders are ones that work on aircraft parts. If it can be fixed, one of these guys will be able to do it.

jdbunda · jdbunda's Garage

If it has to come apart, I am thinking just source a new case and move the rest of the engine into it. Right now, the question is whether it's possible to fix this leak without pulling the whole thing apart. I have a talented welder who is willing to give it a try (thanks jpnovak!).

I get the concern about distorting the case by welding on it, especially with the oil pump right there. With the engine out now, maybe I could clean it up enough to just seal it with JBweld.

911pcar · 06-22-2015, 10:52 AM

To minimize welding trauma in that area or to the case while still adding structural strength, TIG tack weld at strategic locations, then seal with epoxy to a scrupulously clean joint.

But I'm not a welder or a pro engine builder.

Sherwood

jdbunda · jdbunda's Garage

By way of postscript to this, I think porschetub hit the nail on the head about the oddball fitting. I believe it bottomed out, and tightening the oil line on that fitting caused the crack. I also think there was still plenty of stress in that area - I had enlisted some help from fellow Pelican jpnovak yesterday to try to weld it, but as soon as he hit it with any heat, the crack separated further, and it became impossible to do anything with it.

I think it was worth a try - I had hoped to avoid what I am guessing will turn out to be essentially a rebuild by the time I am done, but alas, it was not to be. A new case is on its way. I plan to move the rest of the engine into that case, and I have no doubt I will persuade myself to make a few other changes as I go. Or be persuaded - Jamie already is after me to go to different cams

. As it sits, that engine has around 20k miles on a PO's rebuild. I am hoping it will be otherwise in good shape, but that weird fitting makes me suspicious I might find other cut corners and oddball parts.

Thanks all for the advice. If I decide to do the build myself, look for my thread of bewilderment, coming soon to this forum....

Dpmulvan · 06-26-2015, 12:15 PM

I just went through the same thing, same crack in the same place with stock fitting. I feel your pain! At least will get an engine rebuild under our belts.

Essexmetal · 06-26-2015, 04:11 PM

This type of repair is done on a regular basis. The one thing to note as a safety precaution based on previous comments on washing the joint with brakekleen or acetone is there can not be ANY remnants of the solvent present before you strike an arc with the TIG Torch. There is a strong chance the burning solvent will create Phosgene Gas and your day goes quickly down hill from there. Google the full details.
Rick

Flat6pac · 06-26-2015, 05:32 PM

I wouldn't remove the pipe nipple until the welding is complete.
Bruce

911freek · 911freek's Garage

I have had worse fixed.

Das Schnell Ei · 12:15 PM

you would need to tac it on both sides or as soon as you start to work one side its going to pull the other side open.... you got a few seconds of working time to tac the sides, you dont need to get the case that hot to tig it up with good filler rod

are you going to toss that case half out? if you are I would take a shot at welding it

Walt Fricke · 07-01-2015, 12:16 PM

Perhaps having this crack 360 degrees so it can be removed is not such a bad thing? That way you could insure that both fractured faces, and everything near them, are cleaned of all traces of oil or other contaminants before welding?

A shop once gave up on welding aluminum AN fittings on a 911 external oil thermostat - they thought they hadn't been able to clean it sufficiently. Then it turned out that the TIG gas they were using was, itself, contaminated. They figured this out on their next aluminum TIG job where contamination of the parts was not possible. But perhaps this stands for the fact that it is hard to weld aluminum if the parts are contaminated?