That is exactly right. People without problems with their cars probably wouldn't go searching for sites to talk about how everything is going just swimmingly. I came here because of some issues with a car I'd just bought. Once here, the brain vampires got hold of me, sucked-my frontal lobes out through my nose and threw me into OD to burn incense and mumble weird stuff.

B

Here is some information on Alusil engines and boring/honing techniques. See figure 1.4 Design Details Alusil for the piston coating. I hope this helps:
http://www.msi-motor-service.com/download/broschueren/alu_en.pdf#search='alusil%20engines%20and%20coated%20pistons'

Interestingly, the pdf references the 380, 420, 560, and 600 Mercedes engines as alusil, yet I've never heard of this problem with MBZ before. My 560SEL experience has been pretty bulletproof, same with 380SE - I'm on my second one now. Has anyone out there had any issues with this on their MBZ engine?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

No MB does not have this problem, never have.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Porsche hasn't had any issues either. That's why I say Alusil is a very good material to use in an engine. It's difficult to modify and run custom pistons that aren't a fortune but the engines in stock configuration are pretty much bullet proof.

I'd have to agree with you there. At least in my experience, 944 and 924 engines are pretty bulletproof.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I know of a '99 Boxter that received a new engine at 6000 miles, because of this issue.

Update on the 4.4 BMW, I have it apart and sleeved with iron liners, hyperutectic pistons with high silicone. The OEM pistons had no evidence of tin plating, none.

If the engine bore is Alusil, they have got to be coated. End of story, period, ! Where your engine bores Nickasil? If so, you can run any pistons in a nickasil coated bore. BMW uses nickasil, alusil, and I believe even use iron cylinders.

Both motors( original that blew up, and the used replacement that pushed a head gasket, and damaged cylinder bores) have aluminum cylinders, no plating on pistons.

Ok, that would explain the ruined engine. If your cylinder is aluminum and your pistons are aluminum, your pistons or cylinders have to use a coating. Using like materials in both the piston and bore will cause scuffing and a ruined engine. The coating is very very thin on the piston. Once it's been in an engine for a while you can't even tell there is a coating on the piston but you can tell the difference if there is an uncoated piston and a coated piston side by side. The coated piston will look dull and the uncoated one will look shiney. You can not run aluminum bores and aluminum pistons without some type of coating on either one.

Here is more information on piston coatings and the necessity when using like materials in a piston and bore:
http://xrint.com/patents/us/5884600

http://www.mahlemotorsports.com/C125708F0068F67A/CurrentBaseLink/W26MPEHG188STULEN

Very true. Most all pistoins are plated with tin. It's purpose is to keep the piston from growing cooties in the box. One piston that I use many of, that is not tin plated, is Mahle. The tin plating is a couple of tenths thick. To depend on two tenths worth of tin plating, to keep you safe, is not my idea of good engineering. If I measure a used piston at two-three thousanths under, where do you suppose the tin plating went to? Plateau honing is the key, not tin plating.

With alusil engines, honing the bore to bring the silica molecules to the surface is a must. However, that's for long term durability. The silica impregnated aluminum is very durable but they still need a coated piston to use in the bore. Mahle pistons for use in a alusil engine are coated. They use pistons that are coated with iron. Directly from the Mahle website:

Quote:

For the application in aluminum cylinder surfaces, MAHLE uses its own development, the iron coating FERROSTAN®, or the iron particle reinforced synthetic resin coating FERROPRINT®. These coatings are necessary to enable the combination of aluminum pistons with pure aluminum engine blocks and hence represent an essential contribution to an overall reduction in engine weight.