jshalomo

I just got my engine cases back from the machine shop where they were sleeved. The sleeve job looks great, but I noticed some aluminum flaking inside the case. Does any one know if this is an issue?

Imo000

Did the shop try to clean it up? In the second picture, looks like someone was in there with a die grinder. What did the shop say about the flaking?

Flat6 Innovations

That case appears to have been porous and repaired at the factory. The machine shop should have consulted with you about this. I'd hope they know what this means.

jshalomo

I didn't talk to the shop yet and didn't notice it when I left the shop as the 2 case halves were joined and wrapped...r the shop told me that they boiled the cases to clean them up, but that obviously wouldn't do it...it does like a die grinder was involved though.

jshalomo

They didn't call me...as it is not in a critical place, do you think it's an issue?

Macster

Looks to be on a water jacket wall. That's a critical place in that if there is porosity this could allow coolant to seep into the crankcase.

Flat6 Innovations

Refer back to the machine shop and ask why they didn't bring this up.

jshalomo

I will....is there anything they can do about it? Should I just epoxy it or something??

jshalomo

Oh that sucks. I think it's on the oil side of the water jacket wall, no?

Flat6 Innovations

They should know how to address this.

Macster

Yes, the oil side of the water jacket wall. If (big if) there is porosity or porosity develops coolant could leak into the oil and possibly into one or more of the engine case stud holes.

Now I'm not saying porosity would develop. Based on my exposure to (non Porsche engine) castings it would not surprise me if a few engine castings come from the factory with some porosity (or suspected) porosity addressed. It has been my observation in a foundry there is at least one welder who's job it is to weld up castings that would otherwise be scraped due to casting porosity.

Generally if the engine was porosity free before it was disassembled and cleaned up it should remain porosity free afterwards.

Maybe.

The cleaning could find a weakness in the casting -- most likely where the casting had been repaired before -- and open up a new path for a possible leak to develop over time.

However, even the small risk of a leak developing at this critical point warrants I think a real need to get this addressed properly so there is no chance of any porosity to develop and allowing the coolant to go anywhere outside of the the cooling passages.

JR is right. The shop should know what to do about this. And you should ask the shop.

jshalomo

Thanks Macster. I am on my way back to the engine shop now...

Paul Waterloo

Being a dummy on this subject, in the first picture, it appears that the surface might of been flame sprayed to provide a suitable barrier?

jshalomo

I spoke with my machine shop and he concurred with JR and Macster in regard to a possible repair at the factory...He said he didn't notice it at all when he was working on it and was surprised to see it because this is something he would have taken care of had he seen it. He thinks the cleaning process may have exposed it after all the work was completed.

He didn't think it was a big deal because both sides of the wall touch oil so porosity would not be an issue, and the fix is to just smooth it out to remove any possibility of it flaking a little more and possibly contaminating the oil in the future.... He said he can use something like JB Weld if I insisted, but he thought it wasn't necessary...

alpine003

Lol. That doesn't sound professional at all. I take that back. It is professional if you're a redneck from the south. No offense to anyone.