Im taking my N62 V8 engine down to the block, im going to drop it off at a local BMW shop once removed. id really love to check the cylinder walls but i heard you cant hone alusil blocks like usual has any mechanic had experience with these blocks? is it even possible to have them honed to inspect for damage? also lets say the engine may have to be bored over, then that would just make this block useless if they cant even be honed?
You visually inspect and measure the cylinders to determine if they need to be bored.
And honing and boring are two different things
Tester
yes. i need to hone the block to check for damage or deep scratches, because im pretty sure piston rings are gone. due to car losing compression. or hopefully not a bent rodā¦which would be even worse damage. i need to check to see if they will have to be bored before i take it off. but i heard you cant just go to town with honing an alusil block because of the silicone crystals for the piston to ride on. just seeing if anyone has an any experience with these before. this engine hasnt been bored before. its still a stock block
I would hope that the shop sleeved the block if it was mine.
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Honing would remove scratches, itās not a check for them.
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You need to check for damage or deep scratches BEFORE honing.
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Boring the cylinders removes material from the cylinder walls to remove deep scratches and makes the cylinders round and straight.
Honing the cylinders puts a cross-hatch pattern on the cylinder walls to so the piston rings seat properly when the engine is put into service.
Tester
Google āhoning alusil engine blocksā and youāll get links to BMW, Mercedes, and Audi forums with lots of information. Looks like you can hone, bore, and sleeve them, depending on condition. But it takes an expert shop to do that.
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Look for a machine shop that does those engines, let the experts handle it from thereā¦
Why would some oil (ATF, Marvel) and Scotch-Brite or whatever pads and brake cleaner not clean them up enough to check for damage??
Machine shop is still your best option if you want it done right, might have to ship it to and fromā¦ Money? you are building a BMW, get over itā¦ 
Or save yourself a lot of money and LS swap itā¦ lol
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Based on this and your other post, it seems like you are the type who just wants to throw a lot of money at this project without first doing an analysis of what it really needs.
For the brief time that it didnāt have oil pressure, you may have done damage to the valve train and not done any to the block or rings. But removing the heads will reveal this. Donāt teardown the block if you donāt need to.
If you do need to replace the rings and the block still shows a good cross hatch pattern from the factory honing, you may be able to get away with a 600 grit diamond hone of the cylinder walls. This just removes the tops of the peaks of the old honing process and will allow the new rings to seat quickly.
You will need to consult with a certified BMW mechanic on this. They may also be able to do the acid etch in the shop to expose the silicon crystals if needed. BTW silicone is the rubber sealant, silicon is a hard metal.
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I see. Im not doing this myself lol!!! I just needed to know if honing these motors was even possible. I got the $$$. But if you cant hone them or bore these blocks i wasnt gonna worry about. But as long as its possible.
I see. Im not doing this myself lol!!! I just needed to know if honing these motors was even possible.im just tearing it down to inspect damage. I got the $$$. But if you cant hone them or bore these blocks i wasnt gonna worry about. But as long as its possible.
Hereās a ton of info
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Okay. Let me ask would the valve train create a knocking? When it was running there was knocking or a loud tapping? Thatās what is leading me to believe itās is possible it spun a rod quickly. Which I didnāt take the motor out of the car yet. I was asking questions before hand. I have only got the motor down to the intake manifold pulled out, along with fuel rail, Throttle body, sensors are all disconnected on the main wiring harness. Because thatās the only way to even get this intake manifold out. But along the way you have to remove the Valvetronic Motors to have enough room to get the fuel rail out. But I noticed scuffs on the eccentric gear I wish I could post photos because they look kinda bad and also on the valvetronic motor itself.
There are so many things that can cause a knocking or tapping. I once had a timing gear that got loose and it sounded exactly like a spun rod bearing. Tightened down the gear and all was good.
Is this one of those engines where the cam moves up and down to vary valve lift and duration? I would not know where to begin on troubleshooting one of those. I would suspect that your issues are there though rather than in the block.
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If thereās damage the block is basically done for, Iāve seen them sleeved with varying degrees of success. To be honest there a very tough block and rarely show damage if everything else is something like and they havenāt been overheated.
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How do you know the engine lost compression? Did you run a test? How many cylinders low? Did you run a leak down test?
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Sometimes a used motor is better option. Better, not best.
Or get a really big shoehorn and put in a 413 for some real grunt.
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Naw, go with a 400 āBā block, takes up a little less room, throw a 4.250" stroker crank in a 0.040" over (4.380") bore for a stump pulling 512ci low deck big block Moparā¦ hehe
But I like where you are going with itā¦ 
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