I just happened to be looking under my car whilst on a ramp and noticed what looks like hair line cracks in the case. It runs around the moulding on the rhs case half opposite the oil drain plug on the lhs case.

Here is a picture (apologies but only have my phone to snap with at the moment). I'll try post a better picture later on.

So, should I be worried about this. For all I know its been there years but has anyone seems something similar? Will it get worse? Can it be repaired with engine in situ? What material is the case and can it be welded? etc.

Appreciate any input on this.... I really hope this is not a time bomb as just completed top end rebuild and replacement of oil lines..

 

I have those also. I think they are cooling marks from the casting of the piece.

 

I've seen similar in mine.
I wouldn't sweat it.
That is until it grows in gap, length... or it leaks. Which it probably won't.

(For length checking, simply mark both ends of the crack with an indelible ink pen and periodically monitor.)

 

Are you sure that's not a casting mark?

 

Could be a shrinkage crack from when the casting cooled, but I doubt it. Possibly it is a transfer from the mould. Put a scratch mark at the tip and check after a few weeks. If it grows past the scratch mark, start to worry. If it does not grow, you are fine. Possibly you can polish the area and get rid of the mark altogether.

 

Its hard to tell from your picture but it does look like casting marks,.........(unless you are inadvertently backed over something),...

 

Hi guys
thanks for the replies. I see why you are all mentioning casting marks but my photo is a bit rubbish. It has the form of a brittle fracture that is slowly propagating (either through heat cycles or stress). I'll get a decent camera with macro and repost a decent image.

Good idea, I will mark the ends to check for any growth.

What is the case made of and can it be welded?

 

Well, if it is a crack that is propagating, the standard aeronautical fix is to stop-drill the crack ends with a fine drill bit. Not sure if that would help!

H

 

Please tell me that's not out of the budget airlines procedure book... !

 

That procedure is only applicable to the airframe skins not the engine.

I had an IO-360 that had a bad crack in the case. It was too bad to weld so the cure was to replace the crankcase. Then "while you're in there" struck, and we decided to do an overhaul on a midtime engine.

JNeteler

 

ok guys, I have some better photographs now. What do you think on seeing these? cracks or casting marks? Anyone got something similar (still like to know if case can be welded)?

 

not 100% but does look like a crack

 

Looks like it bottomed out given the gouges in the aluminum. The impact probably weakened the case and started the crack. Watch it for a while and see if its propogating. The pen marks are a good idea. Does not appear to be leaking, which is a good thing.

 

I would scrub that areas very thoroughly with brake cleaner for a better look at the cracks without any oil or grease at those lines.

Then, I would have that Zyglow'ed to determine whether they truly ar cracks or not. This is a crack-detection procedure for non-ferrous metals.

The case is aluminium and can be welded in that area, however the engine MUST be totally disassembled and the case degreased on both inside and outside before this can be properly done.

 

If you run a fingernail over it , is it raised ?
It looks to me from the photos , to be raised .