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

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

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.

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.

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

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.

I probably have a good used alucil ring.
Bruce