I guess this is bad news

[elflamo]

Do I need a new case halve, or can this be welded or fixed otherwise?

Thx

Dennis

[flat6pilot]

Is it even leaking? It's hard to tell in the photo.

That's the oil return neck isn't it?

JB Weld can sometimes work miracles. A little dab over that and it might be ok. I don't believe it's that high pressure at that location, is it?

[304065]

Dennis, the dreaded crack in the oil-out fitting!

Matching numbers case? Fix it.

Non-matching numbers case? Proceed as follows:

911S case - Fix it
911E case- have a beer and think about it
911T case- get a replacement case

Final point:

Magnesium 7R, lots of machine work done- fix it (and have line bore done)
Stock 4R '72 case, never been open- fix it (and have oil bypass and line bore done)
1R or 2R from earlier car. . . get a replacement case, the machine work is too expensive.

You don't want to hear this but you're looking at a complete teardown to the crank. Look on the bright side, you can get rid of those two piece oil return tubes!

How did this happen? That fitting doesn't look like a 26mm, it looks like a 30mm, which means it happened when somebody changed the oil-out fitting, right?

Where do you send it? Once it's disassembled, send it to Ollie's: http://www.olliesmachine.com/. Round trip shipping from Europe is cheaper than having somebody inexperienced screw it up. Unless, of course, you're junking the case.

Good luck! Hope this helps.

[elflamo]

Thanks for the replies

Is this a common issue?

Yes, it's the oil return adaptor from the left case halve. It leaks a little, but I haven't even started the engine yet (after 5yrs of resto). So I guess once the oil becomes hot and thin, it will leak more.

I'm pretty sure I've caused this myself when I needed to refit the adaptor when installing a new return line/hose to the filter console. Unfortunatley I happened to have the torque wrench reversed, so it never warned me the specified torque was already reached.... At the time, I didn't see no damage, but it probably cracked after a while.

It's a 5R case halve of my 911S engine. The other side is a 4R. Should I first try to JB weld it, see if it holds? I'm afraid the crack will progress further?

If the JB weld holds then at least I can start the engine and see if there are any other issues I need to be aware of and that might warrant a tear down...

Bummer

[elflamo]

By the way, I just installed the two-piece return tubes. Are there issues with them?

[d.a.autry]

As I'm a good redneck. . .I'd personally at least TRY the JB weld. Problem is getting it to stick. I would drain the sump, CLEAN the area thoroughly and make SURE there is no oils, etc. (I don't know what to suggest here, but I don't think brake parts cleaner would be harmful to the case) Being that the JB Weld will be upside down while curing, I would let it develop enough consistency so that it won't run off before you apply it, but not so much that it won't adhere to the case. This may be a trial and error thing to get right. OR you could somehow wrap this with a wax paper after applying in order to keep the JB Weld in place.

I'll probably be crucified for saying this, but I would even apply this around the first fitting up to it's hex to ensure it won't leak from around the threads. If it ever needs to come off, the JB Weld will give.

Now, I'm not proud of this and it took some good coverage with the JB Weld, but I was able to stop a pressure leak from around a crack on a boss near the pump housing on a 944 block. App. 30k miles on it since and still no leak. BTW, I would let the JB Weld set up for at least 24 hours, longer if it's cool (below 75 F).

If this stops the leak and you find you have no other issues requiring a tear down, then you're $$$ way ahead. If you've also backed off on the torque, then I also don't think the crack will travel any further.

Also, if you're going to go the route of R&R with someplace stateside like Ollie's and you don't care about the 5r case, then I'd save myself the shipping out cost, let them find you a good local 7r case and apply all the updates, then just have that shipped to you.

[Steve@Rennsport]

I totally concur with John,...fix it properly: do it right. Don't do a "Rube Goldberg" repair,...

That means no JB Weld, as that can be a real bastard to remove at a later date and your car/engine deserves better.

The case can be welded by competent personnel; after that it will need to be line-bored after the case halves are machined flat again.

[elflamo]

Thanks again for the replies people.

I will ponder some more about a temp fix to assess further engine quality (and tranny quality).

I've read on other threads about the flattening of the case halves and line boring. For my understanding: why is that needed after the welding?

Cheers

Dennis

[billjam]

Originally Posted by Steve@Rennsport

I totally concur with John,...fix it properly: do it right. Don't do a "Rube Goldberg" repair,...

That means no JB Weld, as that can be a real bastard to remove at a later date and your car/engine deserves better.

The case can be welded by competent personnel; after that it will need to be line-bored after the case halves are machined flat again.

Steve, do you really think a small repair in this area warrants a line-bore?
I just can't see that a localised weld here is going to put enough heat into the case to distort it, especially if the halves are bolted together during welding.
I have had much bigger repairs done without needing a line-bore.
I'd be tempted to get it welded first, then check that the crank spins OK before I went as far as line-boring and re-facing.

[304065]

Guys, it's not the welding that distorts the case, it distorts when you split the case.

First of all, that location is precisely the spot where hot, dirty oil gets sucked out of the case by the suction side of the oil pump and pushed into the lines to the cooler. The odds of getting any epoxy to adhere are slim-- you would have to drop the heat exchanger (without breaking the exhaust studs), drain the oil, remove the oil-out fitting, clean everything, find a way to force epoxy into the crack without getting it in the case or filling the threads, then reassemble everything and expect it to hold through the heat cycles and vibration of normal operation.

Can you just ignore it and leave it alone? I guess so, but cracks tend to propagate in magnesium, and you don't want a small crack to develop into a big one. The engine in #806 is built on a 911T case because the original 911E case was junked. . . guess why. . .due to a crack in the oil-out fitting, exactly the same spot as yours.

The idea that you could weld this in situ is not a good one-- it's magnesium, for heaven's sakes. These things are best welded in a shielding box filled with argon.

[d.a.autry]

Well. . . . okay. . . but, let's be honest here.

Yes, the PROPER thing to do is to tear it down, have it welded, and perform all the standard items that we typically see done to these cases. (alignbore, certs, squirts, etc.)

The real area of concern I personally see here is travel of the original fracture as stated above.

The bottom line completely depends upon your budget and your desires with the car (#'s, originality, authenticity and such). There are some who will go to the same forests, mill the same trees and custom mix the same varnish when restoring interior pieces of a RR Princess, . . . I'd use N. Ga. pine and Minwax So. . . .consider the source.

End all to it. . . do you WANT to have that particular case? If not, go with a better one.


Edited to add.

And BTW Steve. . .to 'Rube Goldberg' it. . one would use the JB, then do something like encase the entire assy. in a D-9 crankcase to confirm the leak would be sealed, the interior area of which would be cooled using DC-3 props and a R-1820 Cyclone. Remember, his cartoons set about the production of the game 'Mouse Trap' and inspired further genius of the likes of Hugh Harman and Rudolf Ising.

http://www.rubegoldberg.com/

[JFairman]

I have no idea if this would work but you can braze aluminum with a torch and aluminum brazing rod.

Google aluminum brazing and see what you think. There's alot of you tube videos of people doing it with aluminum brazing rods and a map gas torch.

People have been brazing intercoolers, AC condensors, and evaporators for a while and you can do thick aluminum and magnesium castings while a steel bolt or fitting is in place because the repair job doesn't get hot enough to melt or affect the steel part.
I did not know this until I saw it being done in a video.

Maybe you could drain all the oil and clean it good enough with brake clean, compressed air blown into the crack, a stainless steel brush, and braze it up and seal the crack.
I'm just saying maybe though... because I don't know if it would work or how long it would last if it seemed to work at first.
I'd be tempted to try it first rather than JB weld or taking the whole thing apart.

YouTube - Brazing Aluminum
YouTube - How to Braze 1/8" Gauge Aluminum

Google

[Steve@Rennsport]

Originally Posted by 304065

Guys, it's not the welding that distorts the case, it distorts when you split the case.

First of all, that location is precisely the spot where hot, dirty oil gets sucked out of the case by the suction side of the oil pump and pushed into the lines to the cooler. The odds of getting any epoxy to adhere are slim-- you would have to drop the heat exchanger (without breaking the exhaust studs), drain the oil, remove the oil-out fitting, clean everything, find a way to force epoxy into the crack without getting it in the case or filling the threads, then reassemble everything and expect it to hold through the heat cycles and vibration of normal operation.

Can you just ignore it and leave it alone? I guess so, but cracks tend to propagate in magnesium, and you don't want a small crack to develop into a big one. The engine in #806 is built on a 911T case because the original 911E case was junked. . . guess why. . .due to a crack in the oil-out fitting, exactly the same spot as yours.

The idea that you could weld this in situ is not a good one-- it's magnesium, for heaven's sakes. These things are best welded in a shielding box filled with argon.

Spot-on,........thats stellar information.

[BURN-BROS]

IMHO, I would take the car to an experienced welder. One with a good deal of aluminum/magnesium experience. Get an opinion from him on how he would tackle the job. In fact get a couple of opinions. Check with your local airports for good referals.

Ideally I would split the case for the repair, but there is some great talent out there and is definetly worth looking into.

[Walt Fricke]

Elf:

Regardless of how you deal with this issue, I wouldn't worry about your oil return tubes!

I like to run three stock tubes and one collapsible one, which is located next to that fitting. That way you can remove it in order to get at the big nut right nearby as might be needed, and then put it back. Very useful sometimes.

I like the stock one piece return tubes because they are a little lighter and thinner usually (thinking race car here), and having fewer moving parts is generally a good thing. There are a rather baffling number of different collapsibles out there, but none of the several I have used have caused me problems. The 2.8 I bought assembled last summer has four collapsibles with giant springs pushing their ends into their holes. First I had seen of that variation. Works just fine. If ever I need to rebuild it I might just put them back in as is.

I think our esteemed moderator was trying to inject some humor in an otherwise unfortunate situation.

Walt

[Eagledriver]

For those who are suggesting a line bore, I think you missed the fact that this engine is a fresh rebuild that hasn't even been started yet. Presumably it's been line bored already. It would certainly be worth trying without another line bore.

-Andy

[304065]

Good point Andy, and one that I overlooked. In that case, the answer is, absolutely tear it down, you're looking at a gasket set and some sealants, but it's a lot faster taking an engine apart that has never been run than it is bringing back one that's had one cheap rebuild since it left the factory (which was the case with my engine).

Dennis, I bet you could fix this for around $600-- tear it back down and build it back up, as follows:

New gasket set $200
574 $25
Round trip shipping of affected case half from Netherlands to Lake Havasu City $200
Weld up fitting and maching. . . I'm guessing $100
One piece oil return tubes $55

Teardown and rebuild. . . 25 hours. . . probably faster.

Not bad, considering.

[Walt Fricke]

Shoot, new gasket set? Why? It hasn't been run. The gaskets you installed will still work fine after the rebuild.

If you like to glue gaskets on, assuming you glued nothing to the case they should all be fine.

Buy a set of the little throughbolt O rings (you can count on some of those having been somewhat shredded no matter how careful you were) and call it good.

For that matter, I'd be astounded if there were not capable welders in Europe. The engines came from there to start with.

Walt

[Bob Goding]

if it was mine. I would remove the fitting, clean the threads and the crack with carb cleaner,work some JB Weld into the crack and put a jubilee clamp, really tight,around the boss. You may have to clean some lumps off the outside of the boss to seat the clamp properly, ---Then JB Weld the fitting in [not too tight!] Should last until the next teardown.
Good luck