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Old 10-28-2017, 12:13 PM
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Default Trying to save alusil cylinders

Hi all.

I’ve got an ‘83 911SC with broken head studs. I bought Wayne Dempsey’s book on rebuilding 911 motors. In it, it suggests that alumasil cylinders can be saved on low mileage cars during a “rebuild” if you pull the wristpins and remove the pistons and cylinders as one unit. I’ve done this with success except for the #5 cylinder. Without going into detail, I managed to break the oil ring on that piston. I’ve heard chatter both ways. It’s impossible to rering alumasil cylinders, or that it can be done, but there isn’t a 100% success rate. I was really hoping to avoid dropping the $4k on new cylinders and pistons in this 85k motor.

How boned am I?

Thanks, Matt
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Old 10-28-2017, 08:06 PM
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1) You have no choice at this point but to rering that cylinder. No experience if it will work or not. You're going to have to make a judgement call on it.
2) possible option. can you send the cylinders to LN to have them nicasil coated? Would require new pistons.
3) its "Alusil" not alumasil
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Old 10-29-2017, 11:05 AM
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I knew I’d have to put a new ring on it.. Who is LN?

Sorry for the alusil typo.. I keep saying it alumasil, not sure why.
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Old 10-29-2017, 12:27 PM
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https://lnengineering.com
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Old 10-30-2017, 11:59 AM
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Allied Machine Shop in Falls Church has/had the correct Sunnen equipment to rehone the Alusil cyls. Try a search, as I think this has been discussed before. I've personally had good luck hand honing with scotchbrite/WD40 and new rings. Make sure to run it hard up/down the RPM range as soon as it gets up to temp continually for the 1st 100 miles.
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Old 10-30-2017, 04:37 PM
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Not saying it does not work but I don't see where hand honing can produce the original intended surface. Perhaps after some time the rings hone the aluminum away leaving only the silicon as wear surface?

http://www.sunnen.com/NewsDetails.aspx?NewsID=11
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Old 10-31-2017, 09:42 AM
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If memory serves correct, this home remedy is not so much "honing" as it is cleaning/deglazing to expose the original finish as much as possible. This is the fingers crossed solution if low miles, well maintained, and measure within spec.
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Old 12-03-2017, 09:32 AM
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I probably have a good used alucil ring.
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