I don't know if it was in this thread or not, but someone (maybe Henry Schmidt from Supertec) used a surface roughness device and found that scrubbing/scuffing Nikasil cylinders with a scrotchbrite pad replicated the OEM roughness figures almost exactly. Other methods created a surface that would surely wear out the rings quickly.....wish I could find it. Wonder what the OEM roughness figures for Alucil were/are and if those could be replicated using various techniques (other than the AN paste).

EDIT: Found it. BTW: catca, think this was in response to your initial honing question.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/163663-do-i-need-hone.html

Wow, ya looks very aggressive. I bet that you could feel that with your finger.:eek:

Charlie, you are right. I have had good success with the scothbrite technique on Nickasil. I am picking up another set of cylinders for this motor and having a local machine shop due the Sunnen process on them that is mentioned in this thread. I will post pics of them when they are done. Won't be until around the end of the month though.

Jeff

I have an old cylinder that Rondinone has measured. I'm having it re-finished 'professionally' and Rondinone will measure it again. I'll also post some pictures for everyone. It's not dead yet...

Here's another data point. I rebuilt Rick Lee's engine over the winter reusing his Alucil p/c's. I had a local p-shop measure/inspect and clean them in a BF parts washer. They also recommended the scrotchbrite method.

Last I heard, oil consumption was 1/2 quart in 1500 miles, which included a 3 day track event. 5K miles on rebuild.

What the heck. THere is no way someone can look at the crummy picts on this site and predict the performance of the honing operation.

Maybe the grooves, if they really are deeper will hold more oil and consequently do a better job lubing the rings. Just speculating.

Note for the anal. This was not a criticism of this excellent site. Just acknowledging the limitations of the limited resolution available.

Lost in upstate NY but near Watkins Glen and good cars.

Charlie, just to clarify:
Did the machine shop use the scotch brite or just clean them in the parts washer?

This thread has gotten monlithic, so I am having trouble searching it to answer my question. Everyone here that I can see is talking about reconditioning Alusil cylinders that are within factory spec.

Can Alusils be overbored and then treated to be totally like new? For example, if you wanted to bore an Alusil 2.7 to 90.5 or 91mm then finish the cylinder, is this feasible. Are they strong enough to take the overbore? It seems this would be the ideal way to get a perfect surface.

Overbore,yes. The problem would be getting pistons.
The KS pistons are coated to last longer. I'm not sure anyone is doing that. If they are I'd like to know. Unless your in stock class,why not go to 100mm?
Good question:
I wonder how long a standard (typical like JE) aftermarket piston would last?
I've herd people that race rebuild often, so this might be an option for them.

I'm still holding everyone up. I am working 12 hours per day, BUT, I will take of early one day this week, get the used cylinder 'buffed' and get it to Adam for measuring.

I would like to see you fit 100 mm barrels on a 2.7 :)

Sorry, I was thinking 3.0 (hasn't that been done?)

Hmmmmmmmmmm; what is this coating? I seem to recall it is some sort of iron(?) deposition coating? I can't imagine that some of the more modern ceramic coatings wouldn't serve the same purpose either as well or better. Perhaps this needs to be researched. Coated JEs in rebored alusils would be the shi...

I know MotorMeister says that htey can recoat the pistons. If they can do it, I am sure someone else does.

Yes, they have some kind of iron plating.
I think there was a tread about ceramic coatings on pistons. It was fine on race engines (with frequent teardowns and replating), but on a street engine it wore out to fast to be usefull.

I'd take anything MM says with a grain of salt...

Indeed. That is why I said "someone else does." ;)

Pistons with teflon antifriction coating.
http://forums.pelicanparts.com/uploa...1116711838.jpg

http://forums.pelicanparts.com/showthread.php?s=&threadid=210999&highlight=cerami c+AND+coating

:) indeed!

Question: Are alusil cylinders alusil strait through?