Quote:
Originally Posted by aureliusmax
sent your old block to Poland they have rebuilders who can reapply the alusil
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Nikasil maybe? I thought that Alusil was the the follow-on to the Nikasil coating used in earlier all-aluminum motors that had the problems with sulfur fuel. Alusil was the process that physically incorporated the silicon into the aluminum block. I think the issue with repairing bores is that a normal hone or bore wont work. Some sort of special process is used that takes a fraction of the aluminum off the bore but leaves the silicon crystals exposed to a very slight degree for the rings to ride on.
Finding shops (at least in the US) set up to do this hone correctly is a challenge. The pretty high-speed Indy Porsche place near me (with a racing operation) won't do this work and reccommends sourcing a used block in better shape for their customers with trashed alusil blocks. On the plus side, the process makes for a very strong and durable block that can last a long, long time, but I think heat is the big enemy for these blocks.
My new shed/workshop is almost complete, and I'll be able to start the rebuild on the 4.4 that came out of my X5. Fortunately, 4.4 blocks are a dime a dozen online so if the block is bad I can likely source a good one.