I doubt if a build could be created with room for a set of Hooker headers
What, a BMW with fender well exit headers wouldnāt be cool?? 
Or demo style, straight up and out the hoodā¦
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Iām not familiar with Alusil but I am familiar with Nikasil coating, which was the bane of early Eur Jaguar XK-8ās.
Hereās a link that you may want to considerā¦
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Based on the link, it looks like a replacement low mileage used engine is probably the best choice. Low mileage might assure that the alusil coating has not worn off the cylinder walls. If the OP wants to be completely sure, a rebuilt engine with the cylinder walls inspected would be an option. Just to be clear, I mean another N62 engine.
The Alusil doesnāt use a coating, thatās why it replaced the Nikasil that quickly wore out with high sulfur gas.
Well, some interesting info in that article:
After the engine block is die cast at low pressure, the silicon particles on the bore surface are exposed by etching away the aluminium. The resulting silicon particles vary in size from 20 to 70 Ī¼m. The bore is not honed like Nikasil or in conventional engines.
Unfortunately, Alusil is not durable. It wears twice as fast as cast iron. The main reason is that the silicon particles actually fall off overtime. It is the primary culprit for premature engine wear in German cars, with oil consumption being an early sign. Also unfortunate is the fact that Alusil blocks cannot be restored. There are only two possible repair options, to sleeve it or to coat it with Nikasil. Since almost nobody coats Nikasil, the only realistic choice is to add steel liners. This is a very expensive repair, and it is very difficult to do correctly.
So, you canāt really hone it let alone bore it and the restoration process is very expensive. Hence the one-time use comments I see referenced elsewhere.
If it was burning any oil prior to the events leading up to this state, or there is any damage whatsoever, itās a lost cause financially.
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@TwinTurbo, I have to question the credibility of the author of your article. Has this article been peer reviewed? Having worked in a foundry that die cast aluminum cylinder heads, I see things in your reference that do not make any sense.
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OP needs to have block checked at shop. They can tell him if it can be āfixedā.
Itās not my article, It was posted by someone else and I merely read it and quoted some aspects of it. I didnāt see any inconsistencies with other articles I have read about the topic. If you have anything to dispute with the parts I cited, why not lay them out here?
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You are right, it was not your article, it was @Beancounter that posted it. The author of the article seems to be saying that the bores are net cast and etched. I donāt believe that you can die cast the bores, they have to have sand cores or you use the lost wax method of casting, which is too labor intensive for high speed production lines.
Even if someone found a way to diecast the bores, the bores would still have to be bored and honed before the etching is done. Not sure how practical the etching process would be for a small shop.
Edit: I went to the homepage of that article and it is not written by an accredited expert. In fact, this statement is on the home page.
āThis website is dedicated to my thoughts and my photos.ā
The production of these blocks has been around since the late 70s if Iām not mistaken. There is tons of information available on the process of making them. They started out as a hypereutectic alloy that was simply cast into the stock type of mold. The alloy was uniformly used throughout the block. Post casting machining was still done to the block with boring and honing but the honing process was specialized in the type of oil and abrasives used. An etching process followed that affected the aluminum but not the silicon. Not overtly expensive and in fact, done as a cost reduction overall in the manufacturing of an engine.
Later, they tried to reduce costs further by using an insert for the cylinder sleeve that was essentially a wax impregnated with silicon (Lokasil?). While casting with pure aluminum, the wax would melt and fill the voids between the silicon bits. This was too tricky of a process and often resulted in a separation between the cylinder āsleeveā and the rest of the block.
At any rate, you can look this stuff up too. The āetchingā process is not expensive or more time consuming, they just use a different paste during the lapping and honing processes.
I still remember the good old days when we still used a hammer and chisel to carve out cylinder blocksā¦
sorry, couldnāt help myself.
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1 qt of oil every 500mi is cheaper then new motor
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I guess weāll never hear back about the compression, tests run, etcā¦
Oh but sir you will hear about it. This motor has had me busy, and between work its been a fun week. And enjoying a butt load of snow in my areaā¦but anyways DEEP BREATH
So ive been stripping the motor down, and pulling sensors and ripping my hair out. Because the N62 doesnt let you just pull things out simply. The motor is the ribux cube of V8s. Im not 100% its losing compression i havent done a compression testā¦ that was my guess. And i eventually will do it when i get there. BUTā¦thanks to Darron, and his bmw expertise. Things are actually so far pointing to the camshaft and not the block or engine itself. Hence may be why its cranking and cranking, but not firing. I got the OBD codes. And its all a black hole of camshaft codes. Leading me to belive its jumped timing. I think maybe the crack in the housing blew alot of compression out and the chain jumped. I pulled the valvetronic motors out and the essentric gear inside the camshaft has some roughed up scarring. Ive spoke with some other bmw guys and they told me this isnt the first time they heard of that oil housing getting damaged on a 5 serie and the 545i with the 4.4v8. And it all caused timing issuesā¦Right nowā¦im getting the VCs off to see inside camshaft, and timing chain. Then im gonna drop the oil pan and see for any metal or chain debris. The motor actually may be good after all but still alot of work. Ive got to wait on the timing tool to arrive befire removing vcs
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You had a hammer AND a chisel?? Oh, an aristocrat eh? 
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If it jumped timing more than a tooth or two, then it likely would have bent some valves. You will have to pull the timing chain covers off first. Iām not familiar with BMW engines specifically, but most engines that use timing chains instead of a timing belt will have a small inspection cover on each bank that is relatively easy to remove.
You will need a service manual to get the procedure for inspecting the timing. There should be colored links on the timing chain that will align with marks on the head or VVT on the end f the cam. BUT, they will only be visible when the crank is TDC on #1 and not all the time. On a Nissan engine, you have to rotate the crankshaft as many as 8 times before they line up because there is more links in the chain than the exact number for them to line up every time. They should only line up when the colored link is lined up with the correct notch on the crankshaft gear. This does not happen with every revolution of the crank and you canāt see that without pulling the whole timing chain cover off.
The point is that if the colored links line up on each cam gear to their correct spots, the chain has most likely not jumped time. It is very difficult for the chain to jump a tooth on the crankshaft gear because of clearances down there. If it did, you would see damage on the timing chain itself.
I was gonna use the tool to check timing. But i cant get the crankshaft pulley to line up with the mark for the tool to lock it. No matter how easy i try to pull it, it jumps TDC about about 1/2inchā¦so im guessing TDC is offā¦the valves look alright from the top of camshaft. And where the manifold sitsā¦ timing chain looks fine, everything is still real tight. But thats just the driver side of the cams. Not passenger.
You do have the plugs out to reduce compression right??