New place to burn a hole ina piston. No crack, just hole.
- Thread starter Fingers
- Start date
Sucks, but thanks for sharing. Seems like even with this, they have an amazing track record.
Would be interesting to know what combination this was being run with (compression/fuel/air/tuning).
I haven't looked at many pistons (especially yours), so I could be WAY off base, but it seems like there's a lot outside the bowl (thinking big/early timing)?
Also as others stated, what is the thickness of that area (seems to me it would be the thinnest area), but I'm sure you know as you drew up the design. Thinner area and ANY casting defects, I think could make for a bad day like this...
Still a great track record regardless, and failure data is always good.
Would be interesting to know what combination this was being run with (compression/fuel/air/tuning).
I haven't looked at many pistons (especially yours), so I could be WAY off base, but it seems like there's a lot outside the bowl (thinking big/early timing)?
Also as others stated, what is the thickness of that area (seems to me it would be the thinnest area), but I'm sure you know as you drew up the design. Thinner area and ANY casting defects, I think could make for a bad day like this...
Still a great track record regardless, and failure data is always good.
They are "thinner" there, but there is very little stress in that area.
NOT an injector issue. At least not directly. Noticed some metal transfer to the pin, where there is none on others. Might be from failure or an indication of the cause like lack of oil cooling.
There is a crack in the skirt. Bead blasted to clean off the carbon. I think this happened after the hole.
NOT an injector issue. At least not directly. Noticed some metal transfer to the pin, where there is none on others. Might be from failure or an indication of the cause like lack of oil cooling.
There is a crack in the skirt. Bead blasted to clean off the carbon. I think this happened after the hole.
It is the only one through the crown that I recall. There have been a few that have cracked below. Right above the pin or on the skirt. Essentially all of those were discovered when the engine was torn down for other issues. Otherwise, the owner was totally unaware of any issues.
For this piston, the oil gallery appears to be a full 0.100" closer to the crown than normal. Probably a casting shift. That alone shouldn't have caused a problem, but I think this piston lost it's oil cooling also based on the metal transfer.
This is a normal piston with the same bowl.
Here is the failed.
For this piston, the oil gallery appears to be a full 0.100" closer to the crown than normal. Probably a casting shift. That alone shouldn't have caused a problem, but I think this piston lost it's oil cooling also based on the metal transfer.
This is a normal piston with the same bowl.
Here is the failed.
In this last picture, you can see how much the oil gallery is tilted. I am going to call the shift the root cause. Right now, I don't know how to detect this going forward.
Looks like mahle cut the bottoms of the pistons up higher or used a different cast. In the cut away between the two, you can see the whole bottom case area is up higher than the first cut away you show
They are essentially the same. There is a little variation from piston to piston, but it is very small and has no impact in this case.
Have you discussed the core shift with them?
Perhaps the issue lies whiten how the are handling the the molds at the casting plant.
Perhaps the issue lies whiten how the are handling the the molds at the casting plant.
Bummer, I though you purchased directly from them and had a semi working relationship. At least enough to contact some one...