I think one of the problems we have with this idea is that all these products are "polishes" and the an-30 silicon paste is an abrasive suspended in a binder.

Well, even the polishes are just abrasives suspended in a gel. The AN-30 is silicon powder, oil, and surfactant. It's likely that you're right about particle size; I'm sure AN-30 is more abrasive than the 3M material which is likely to have a very fine particle size. The intention here was to establish whether or not we could remove aluminum while leaving the silicon intact. That we can do. I picked the 3M polish because the hardness was correct, and I could get it locally for not alot of money. Since it didn't cut as deeply as I had hoped I don't think that it's the best solution. But I'm now confident that this can be done at home using the AN-30.

When I called Sunnen they said they had forty or so 1 pound containers of AN-30 in stock, so they obviously don't sell much. I've decided to go ahead and order some for myself, as I will be reringing my cylinders when the engine goes back together. I guess I'll be the home-sunnen guinnea pig.:p I still need to drag my own cylinders into work and put them on the profilometer (surface tester) in order to assess before and after.

I hope that whoever knows the old timer will post his contact info, and tell him that there's a sizeable niche market that he could make a living off of.

I'm still mulling over yesterday's results. In some places I saw lots of ring material imbedded in the cylinder wall or stuck in pits, which is to be expected, as well as leftover oil, abrasive, and even a large sulfur particle (fuel maybe?). The ring material seemed to pile up in some places, those may be low spots in the wall that are present due to it's age. As for the pits retaining abrasive, I've decided not to be too concerned. I think that a normal healthy cylinder would not have been so pitted in the first place (but then again I don't want to destroy a normal healthy cylinder for an experiment.) So if we're talking about reringing otherwise good cylinders, then the pits wouldn't be an issue. Also, some of the abrasive was retained but not in pits; it was imbedded in the aluminum. That's a second reason to go ahead and get some AN-30.

The pitting was obvious as dark patches. I didn't actually know what the dark patches were until the microscopy. I'll post a picture.

We should all give Jerry another thanks for being such a good sport with his cylinders.:) Thanks, Jerry!

You wanna go halfsies on the grease?

Sure. I'll order it and send half to you.

FWIW, here's the pitted cylinder. So if they look like this it's probably time for a new set.

http://forums.pelicanparts.com/uploa...1074648076.jpg

Here's another picture of the polished region. All the little white pieces (1-3 micron) are pieces of ring or leftover abrasive. Mostly ring. The long island in top center is a silicon particle.

http://forums.pelicanparts.com/uploa...1074648467.jpg

That one does look like it's ready for the recycling bin. Is this one of yours or the high mileage set from J?
Could you do me a favor and measure the skirt thickness (the part that inserts into the case)? Nothing elaborate needed just a dial caliper if you got one.

No way man!:D I'm gonna eBay the whole set...heck they're worth 10X more than what they were new now that all of you scientific types have oogled them.

I see it now, "Own a piece of history! These GENTLY used, highly sought after, out of production KS cylinders used most recently in the Alusil Redemption Project. Bidding starts at $4k NO Reserve!"

Snowman, Rondinone, anh911, I'll need you guys to start writing PhD after your names....

:D

Rondinone,
Those pics are amazing! I have to say, although the factory surface was definetly smoother, the 3-M polished surface looked pretty darned good from my perspective, especially compared to the worn surface. I think too that using the sunnen formula will probably work a bit better; lets face it the 3M route was on the cheap side, but anyone doing this for purposes other than experimentation would surely get the good stuff. If I remember correctly, Jack is using a grape hone to clean up a cyl too, correct? It'll be interesting to see if it has better luck removing all the embbeded material from the surface. Even from the preliminary analysis it indeed looks as though if the cylinder isn't too bad off, they can be cleaned up and reused...gives us hope anyway. Other have proposed the question, but it still seems to be possible int heory anyway to bore the cylinder out, using the sunnen method of the various stages of honing and lapping to get a surface much lke the original factory surface. Now all we need is a successful iron plating experiment with a contemporary piston like a JE or Shasta! Imagine 98mm KS Alusils with Iron coated JE 9.8:1 pistons....

I'm working on the plating bits. Although I have something different than JEs in mind. Don't ask it's a secret for now, I'll spill it as soon as I get more info.
Jerry, you gotta wait till we buy up all the "trash" alusils and corner the used cylinder market before you ebay those collectors items and drive up the price;)

Does someone want to send me a cylinder (Toronto, Canada) for re-work? I'll take it to the old-timer and see what he uses.

email me if you want to send me one. HARPER 'at' fhwelding.com

It's just a good thing you guys are not obsessive.

Could be worse. We could be obsessive compulsive.

Oops I suddenly felt a compulsive urge to edit my post and correct the spelling.

Oh good, I'm glad you did it before I sent you an email and PM about the spelling.

http://www.pelicanparts.com/support/smileys/gitaar.gif http://www.pelicanparts.com/support/smileys/drummer.gif

Got a reply from Bernd Waldhauer, an engineer at KS confirming our findings re: the silicon paste and felt method. Also confirming that 98mm is ok. Quote below:

"Dear Anthony
KS produced for these engines Carrera 3,2 ltr. the ALUSIL liner 88 761 110, and these Alusil can be rehoned and polished with the felt-pads and the silicon paste. In general you could also fit oversize pistons, but we never supplied oversize pistons, the normal way was to replace a liner kit including the piston with rings. So you can remachine aircooled or watercooled liners from ALUSIL, but not NIKASIL, Nickel coated liners ! Your 2. question for remachine the bore size of 95,00 mm to 98,00 mm is possible, but do you have a supplier for oversize pistons ?

Our liners with ALUSIL are running together with pistons with FERROCOAT, the meaning: the complete piston is coated with ferro = iron and a flash of tin. We found out this was a good combination of the silicon crystals (very hard) and the soft iron surface of the piston. "

So the process is confirmed, the fact that KS never supplied oversize is confirmed and the overbore is confirmed but I'm still working on the coating/plating process.

Thanks Bernd
http://www.pelicanparts.com/support/smileys/pray.gif

Bernd is very busy these days!
He was the one that replied to my inquiry!
He now answered my second set of questions in response to you.
BTW, did you invite him to join the discussion?
Bernd da man!
Anthony, you da man too!

HIGH FIVE SLAP WAVY!

That was the worn-out cylinder from Jerry. Mine have 115k and are pretty homogeneous from top to bottom; they're a nice grey matte finish.

>Snowman, Rondinone, anh911, I'll need you guys to start >writing PhD after your names....

I already do, thanks. http://www.pelicanparts.com/support/smileys/wat5.gif

I called Sunnen today and ordered the AN-30. The rep asked what I was going to do with it and I told her I was rebuilding an alusil Porsche engine. She said, "yes, this is what you need." She didn't express any surprise at all that I was going to do it at home.

And here's the KS guy telling us we can use the paste and felt to restore the cylinder like it's no big deal. In retrospect it all seems obvious. Why did nobody try this before?

So when the AN-30 arrives, I'm basically going to polish my six cylinders the same way I polished the tester. I'd like some sort of feedback, so I'm going to run my cylinders through the surface analyzer before and after. When I'm satisfied, the new rings will go in.

I'm pretty confident after the 3M test that I won't rip up the cylinder surface. The only question will be whether or not I remove enough material to allow the new rings to break in. I really hope this works!

And snowman, when you get done with your grape hone send that cylinder on to me and we'll run it through the mill.

¡Viva la revolución! http://www.pelicanparts.com/support/smileys/2ar15.gif

I've been wondering about that too. I worked at several Porsche shops in the 80&90s and never heard anything about this process. All the machine shops told us to toss the alusils. Even the old Mercedes Sl motors that used Alusil were considered throwaways. I think part of the mystery is that KS doesn't do any aftermarket sales, its all OEM, so product support seems limited to very high production users like the auto mfgs. If it wasn't for the internet I doubt it would have been found.

Not knocking KS, they have been very helpful. Just MHO

You know there's a book in here: Rebuilding Techniques for Engines using non-traditional materials.... ;)

We've just done somebody's doctoral dissertation for them.

Hey you guys, did I mention that Alusil cylinders can be reused?

How long before the Prozac and Paxil distributors start trolling for customers?

LOL, Jim!
Come on up and get yer steak dinner, you cheep bastard.
:D

I'm glad somebody understands me. Still thinking about those seats. Perhaps a road trip the weekend after this next one.