http://www.pelicanparts.com/support/...s/beerchug.gif here's to Jerry http://www.pelicanparts.com/support/smileys/clap.gif

I'm on my way to home depot...
ok, maybe not.

Thank's Jerry!

I'll find out more about the machine!

Ok, cylinder went out today. Should be there by Wednesday of next week.

You da man Jerry!

I'll be looking for it Jerry.

While at work today, I got a wild hair up my ass and did a patent search for alusil and KS. I couldn't find the original alusil patent, but I did find two follow-ups from KS and Daimler-Benz. The KS one (below, I'll post the benz one next) is about a different kind of cylinder, I think it's lokasil. But in the introduction they described the alusil process better than I've seen it elsewhere. They also describe nikasil. And most importantly, this is a legal document from KS so we can be assured that it's not bad information. I should note that they do hone the alusil before they etch it. That would account for the crosshatching that we sometimes see, so snowman is right on that account. First is the reference, then the excerpt:


United States Patent 5,131,356
Sick , et al. July 21, 1992


Single cylinder or multicylinder block


Abstract
In a cast linerless single cylinder or multicylinder block made of an aluminum
alloy and intended for use in internal combustion engines, the aluminum matrix
contains embedded silicon particles, which protrude from the sliding surface of
the cylinder. In order to distinctly reduce the cost of the mechanical machining
of the entire surface of the single cylinder or multicylinder block, only the
sliding surface of the cylinder is constituted by a fibrous body which contains
interspersed silicon particles and infiltrated aluminum alloy.


Inventors: Sick; Georg (Beilstein, DE); Everwin; Peter (Bad Rappenau, DE);
Duve; Hans H. (Weinsberg, DE)
Assignee: Kolbenschmidt Aktiengesellschaft (Neckarsulm, DE)
Appl. No.: 666296
Filed: March 8, 1991

This invention relates to a linerless single cylinder or multicylinder block,
which is made of an aluminum alloy and has been cast in a metallic permanent
mold and is intended for use in internal combustion engines and comprises
mechanically smoothened silicon particles which have a size of 20 to 80 .mu.m,
preferably 30 to 60 .mu.m, and are embedded and uniformly distributed in the
aluminum matrix and protrude 0.5 to 10 .mu.m, preferably 2 to 5 .mu.m, from the
sliding surface of the cylinder.

From present-day aspects, aluminum alloys are the most promising materials for
use in motor vehicles and their use tends to increase. In addition to other
advantages, they are lighter in weight than ferrous materials so that
appreciable results will be produced it they are used in the piston and
particularly also in single cylinders and multicylinder blocks, which are the
heaviest components of a motor vehicle. For instance, a saving by 40 to 60% of
weight can be and has been achieved by the use of a multicylinder block made of
aluminum alloys rather than grey cast iron in the engine block. In the
periodical: MTZ Motortechnische Zeitschrift 35 (1974), pages 33-41, a cylinder
is described which is made by low-pressure casting from a hypereutectic
aluminum-silicon alloy of the type AlSi17Cu4. A manufacture by pressure casting
may also be adopted. The silicon grains which are formed in the sliding surface
of the cylinder by a primary precipitation from the hypereutectic aluminum alloy
are uniformly distributed and have a uniform shape and have a grain size between
30 and 80 .mu.m. When the single cylinder or multicylinder block has been cast
the cylinder bore is mechanically machined by rough boring and finish boring and
is rough-honed and finish-honed so that the silicone grain are smoothened and
are initially flush with the surrounding aluminum alloy matrix. After the honing
operation the aluminum alloy matrix is slightly set back from the silicon grains
by an electrochemical treatment so that the silicon grains protrude slightly,
i.e., by 2 to 5 .mu.m, from the unreinforced sliding surface of the cylinder to
provide a carrying structure for he piston rings and the piston skirt. A
cylinder having such a sliding surface can be used only in combination with a
light alloy piston which at least on its skirt is coated with an iron layer
having a thickness of about 20 .mu.m so that contact between the aluminum alloy
matrix of the sliding surface of the cylinder and the light alloy of the piston
will be avoided under all circumstances, even under extreme operating
conditions. The pressure of the iron coating on the piston skirt will
appreciably reduce the wear of the piston skirt and will prevent a seizing
action between the piston skirt and the sliding surface of the cylinder. A
single cylinder on a multicylinder block of the kind described hereinbefore has
the disadvantage that the entire cylinder block has been cast from a
hypereutectic primary aluminum alloy produced at high cost. The high silicon
content involves a higher wear of the tools used to mechanically machine the
cylinder block.

It is also known to make linerless single cylinders and multicylinder blocks of
an aluminum alloy of the type AlSi9Cu 3 in a process in which a nickel base
layer having a thickness of 50 to 80 .mu.m and containing dispersed silicon
carbide particles of 1 to 3 .mu.m is formed by electrodeposition on the surface
of the cylinder bore. Thereafter the sliding surface of the cylinder is honed.
The silicon carbide particles serve as a carrying structure for the rings and
the skirt of the piston. The provision of the nickel dispersion coating involves
an appreciable processing cost. Specifically, the electrodepositing plant must
be provided with means for detoxifying the pretreating baths. The sludge
contained in the spent baths must be collected and must properly be disposed of.
Offtakes having built-in scrubbing plants must be installed in the working
regions of the coating baths. Besides, expensive handling will be required for
regeneration of the cylinder bores in case of repair.

Here's the benz patent. By the way, this is already part of the public record. You can find the rest at the USPTO website. You might note that they say that alusil can be lapped, but that's it's not economical. I tried to find a sunnen patent to see what's in that an-30 paste, but they apparently didn't patent it or didn't patent it in the US.


United States Patent 4,363,708
Rauchle , et al. December 14, 1982


Process for exposing silicon crystals on the surface of a component of an
aluminum alloy of high silicon content


Abstract
A process for exposing silicon crystals on the surface of an aluminum alloy of
high silicon content and with undissolved silicon particles, wherein the
aluminum alloy is connected as the cathode in an electrolyte containing an
aqueous alkali nitrate solution which is at least 0.01 molar with respect to the
nitrate ions and is subjected to electrolysis with a minimum current density of
0.5 A/dm.sup.2 to remove aluminum from the alloy surface without removing
silicon crystals. The electrolyte can also contain at least 0.005 mol/l fluoride
ions and 0.05 mol/l-14 mol/l nitrite ions to suppress generation of hydrogen at
the cathode and oxygen at the anode, respectively.


Inventors: Rauchle; Wilfried (Ostfildern, DE); Preisendanz; Walter (Hardt,
DE); Scholtissek; Leonhard (Stuttgart, DE)
Assignee: Daimler-Benz Aktiengesellschaft (Stuttgart, DE)
Appl. No.: 263909
Filed: May 15, 1981

The invention relates to a process for exposing the silicon crystals at the
surface of an aluminum alloy of high silicon content and with undissolved
silicon particles, by removing the aluminum on the alloy surface. The invention
relates especially to a process for the surface treatment of components,
particularly to frictionally stressed structural parts made of alloys based on
aluminum with a high silicon content, especially cylinders of internal
combustion engines.

Due to their low weight and good thermal properties, aluminum alloys have found
increasing acceptance in automobile engine construction; in particular, cast
alloys having a high silicon content and undissolved silicon particles are used
in this connection. Such alloys contain, besides aluminum, about 6-20% by weight
of Si and, in some cases, additionally about 3-11% by weight of Cu or about 7-9%
by weight of Mg. The so-called hypereutectic alloys are utilized especially
frequently for engine blocks, which are based on aluminum with for example,
about 16-18% by weight of Si, about 4.2-4.9% by weight of Cu and minor amounts
of other elements, such as, for example, 0.45-0.65% by weight of Mg, 0.08-0.2%
by weight of Ti, up to 1% by weight of Fe, and optionally up to about 0.1% by
weight of Mn.

Since aluminum tends to seize under sliding friction, the aluminum is
customarily removed from the respective surface so that silicon crystals project
from the aluminum alloy surface. The sliding surface proper is thus constituted
by silicon, and the aluminum with its seizing tendency is located at a deeper
level.

The exposure of the silicon crystals on the surface has heretofore been effected
by a special honing procedure producing a kind of textured polishing which,
however, is not very suitable for series production, for reasons of
manufacturing technology.

Furthermore, aluminum has been removed from the surface by chemical etching. In
this connection, use was made of acidic baths of nitric acid-hydrofluoric acid
mixtures or phosphoric acid-nitric acid mixtures, for example, 60-90 vol-%
H.sub.3 PO.sub.4 (85% strength), 5-15 vol-% HNO.sub.3 (70% strength), remainder
water up to 15 vol-%, as well as alkaline baths with an aqueous solution
containing about 2-6% by weight of NaOH. The disadvantages in these chemical
etching processes are the poor controllability of the etching attack, especially
in case of exposure depths on the order of 1 .mu.m; the pitting-like attack when
the etching agent is exhausted; as well as the corrosive attack after the
etching procedure proper. The dissolution of the aluminum is effected, more
frequently than with chemical etching, by the use of electric current, wherein
the aluminum is connected as the anode into an electrical circuit with a neutral
electrolyte. However, if aluminum is connected as the anode in an electrolyte,
then a protective passive layer is formed (anodizing). In case of high anodic
load, the thus-formed passive layer can be locally destroyed, resulting in
localized corrosion (pitting); a uniform exposure of the silicon crystals on the
surface is not accomplished. This pitting-like attack, although providing
improved lubrication by the formation of oil pockets, does not result in a
uniform setback of the aluminum matrix. The characteristics in use as a
structural part of an engine of such treated alloy based on aluminum are
satisfactory as long as a setback of the aluminum matrix by a textured polishing
effect is still in existence due to the honing procedure. In honing processes
wherein, on account of a good cutting effect of the honing stones, aluminum and
silicon lie practically in one plane seizing can occur in spite of the oil
pockets. Copper-containing aluminum alloys, as is the case practically always in
the aluminum alloys of high silicon content, are additionally attacked with
pitting under selective dissolution of the actually desirable, hard
intermetallic phases.

Good reaserch!
Thanks!

Is this it? Is the thread dead?? I have a confession to post then..
sad to say but I am deserting the alusil revolution (at least in practise for this motor) I was originally going to do a stock rebuild on my '89 cuz the car is sick nice, body and interior wise and I didn't want to break the cherry. Plus I wanted to do the felt/silicon thing and drive it for 100K miles just because :D Now however I'm going nuts with the motor and the ali's are gonna be history ;)

Wanna donate them to a 3.2 Alusil short stroke experiment?
I would then need to bore them out and find 98 mmpistons that are coated. Are there other coating materials? Can I get JE to make a set and get them coated. Then get the cylinders bored to match?

I don't think we verified how large the alusils can be bored out yet. Not sure on the piston coating either. That discussion didn't get very far. I believe Rondinone thought it was not too difficult but I don't know of any sources.

Re boring Alusils- I can offer to bore a set of cylinders to whatever size is possible and finish honing them using a Sunnin CV- 616 hone per instructions already posted on this link.


THe price is right - FREE. :cool: :cool:
I would be interested in seeing how they perform.

In addition I could hone sample cylinders using differen't methods and them one of you who has the capability could look at them with an electron microscope. Again I would do this for free.

The iron coating on the pistons is required. The main reason is that both cylinder and piston cannot be same material. If they were they would sieze or at least do some very nasty scuffing.

I have finally received all the literature on the flex hones and will post some excerpts soon. My main impression of the flex honing operation is that it is a substitute for using the rings to break in the engine. IN other words flex honing does in a couple of minutes what rings would take up to 10,000 miles to do, and as a consequence the rings are not damaged as much and seat better. THis is due to the hone knocking off the micro peaks in the cylinder wall and aligning them in the same plane, creating small plateaus instead of sharp peaks. The result is a larger surface areal to carry the load and consequently less wear and better oil control.

Any suggestions on plating the pistons? I can call my bro-inlaw tomorrow, he is T&D maker extraordinaire and works on some pretty exotic stuff.

I read parts of Anderson's book again last night. The Max Mortz 3.2 pistons were actually Mahle. I think I read above that they were from the 95mm castings, bored out and the top gasket grove was not cut. There is a picture of a set in Andersons book. That's where the idea of boring out a 3.2 cylinder. (Because they don't have the ring grove.)
I don't think this was my idea. I've read so much in so many diffetent places it's running together. So somebody else probably should get credit.

Snowman, I would love to be the test case but I don't have a set of used carerra Cylinders. I will start a search for them. I'm not good on e-bay so any help would be appreciated. I would think someone should have some lying arround.
Anh911 work your bro.
Maybe we should skip a size to 100 mm?
Were there any later engines with them. I would think the walls would start to get pretty thin or the head studs would be inpacted?

The 100MM units from the later engines have different head stud spacing and it would require mucho mods. I'm sure trying to bore the originals out that far would be impossible - 5mm, i doubt the entire wall thickness is more than 8 to 10.

Easier to just bite the mahle bullet and buy the 98mm for 3.2.

oh, yeah I forgot, once you get into 100mm+ bores and over 10:1 CR you are in twin plug territory, depending on the piston dome design. The MaxM pistons would likely need it as they don't have the single plug squish design.

A reply from KS:

Hallo William ! Some answers to your questions for rehoned Alusil-cylinderblocks or liners. You can remachine and rehone all ALUSIL-blocks and liners, if not, why we can offer oversize pistons. There are two different procedures used , for ORIGINAL equipment we finish the bore-size for a Porsche V-8 engine only with special honing stones. These honing stones are not available now for the aftermarket, for this reason we recommend the process with the felt pads and silicon compound, offered by SUNNEN. We inform about all these items in our brochure: Reconditioning of Aluminium Engines. We can send you this brochure free of charge to your adress. Because the procedure with the silicon compound is a "dirty" operation, we look for honing stones, similar used for Original equipment and we are in discussion with SUNNEN - USA, to produce such honing stones for a good price for the aftermarket. The future will be for the Alusil material, and the coating with Nickel (Nikasil or Galnikal ) would be stopped in short times.
With best regards, Bernd Waldhauer, Senior Service Engineer, Motor Service International.

We might need some help translating ("if not, why we can offer oversized pistons.")
I responded asking where I can buy the pistons? among other things.

Rondinone:
I had a breif discussion with my neighbor.
Here's part of his reply:
Hi Bill,

We have two different instruments in our shop here that might help. 1. An Optical Comparator - (exact model we have can be seen on www.ganesmachinery.com/mitutoyo .
2. Surface finish testor which measure RA (Roughness Average) down to .001" . 3. We do crack analysis via fluorescent dyes that excite a different wave lengths. When we have a particular problem we subcontract out to X ray analysis or ultrasound. Other resources we use include www.michmet.com

I also have the e-mail of one of their engineeers who also is a Porsche fanatic. (He has yet to be advised of this little known info.) I will be sending him a link. Hopefully he will join in the discussion.

So now Kolbenschmitd is on board? This alusil revolution is really picking up steam. I'm tempted to box up my alusils and send them to Germany.

I found the Sunnen AN-30 msds (hazard.com). It's nothing but silicon powder in oil with a little surfactant. I called them up, and they will sell it for $26/lb. I think I'm going to order some if I can't locate anything local that's similar.

When Jerry's cylinder gets here I will do the following: scrub the top 1/3 with the AN-30 or equivalent and felt pads on an engine hone, as described by the pdf above. I'll then cut it up, and compare the bottom 1/3 (factory finish without ring wear) to the middle 1/3 (factory finish with ring wear) and the top 1/3 (presumably good for rering). I will also take some chunks of the middle 1/3 and have them cleaned in a parts washer. I'd like to have JW do that but I have yet to ask him nicely. Then I'll look at those chunks and see what the parts washer did. All the analysis will be done with an electron microscope capable of seeing the surface in great detail, and analyzing the composition so we know exactly what we are looking at.

Snowman that's a kind offer. If you can dig up another cylinder (maybe Jerry?), the please hone the top 1/3 or 1/2 with the grape hone and send it to me (I'll provide my address in a PM). I'll break it up and take a peek at it. I need the bottom to be left unhoned as a control.

If we can examine the grape method, as well as the BFPW and the Sunnen-silicon job, we'll have covered all the important bases. After seeing that benz patent I've decided that any sort of etching would be inappropriate for the home mechanic.

Check out my new signature.

You guys are going to bankrupt me!:D

If snowman is up for it, I can probably find another well used cylinder.

William,

It's nice of you're neighbor to offer his services. I think however that we'll have it all covered. Good work contacting KS.

I cant wait for the outcome! I'm holding off on putting my cylinders on just to see what the results are before I complete my rebuild. For all of those who said Alusils are worth 10 bucks think twice before selling.

Rondinone - I love the new signature quote.

A WHOLE TEN BUCKS!!!:eek:

Crap!!! Adam, I want my cylinder back!!!:D

If anyone wants one or all of the remaining cylinders, you pay shipping...you know where to find me.SmileWavy

edited to make sense....

Bill, great work getting KS onboard. I tried and got no response. It's just a guess but I think he meant, "why would we produce and sell oversize pistons if you couldn't bore them?" or roughly that. Interesting that he did not directly talk about 911 P&Cs. Call me paranoid but I can hear a caveat coming a mile away.

Rondinone - great new sig. sounds like the revolution has a motto!!http://www.pelicanparts.com/support/smileys/2ar15.gif
VIVA Alusil!

Hey, this might be a stupid question but do 3.6s have alusil or the soon to be discontinued ;) niks?

Yes, I am up to it. Send me a cylinder. I will pay return postage too.

An excellent plan.

Rondinone:
I pretty much came to the same conclusion. The "comparitor" machine is what he initially offered to me for measurement of the cylinders and pistons to see hao much they have worn. It seems like a lot of people are experiencing little wear or at least within Porsche specifications.
What do you think of this machine for this purpose?
I believe they use it for quality control.
Anyway, I have nothing for him to measure at the moment. I didn't really know the complete history of my cylinders because they were from a rebuilt engine that the PO installed in the car. Who knows how many miles are on them.

The reply from KS probably took 3-4 weeks on e-mail. I asked them also to send me the document, but I suspect it is what we have seen here. I'll update when I get it. That might take a long time.
Does MSI / KS have a us office?
How would the distribute parts? I've never herd of someone buying replacement KS pistons and/or cylinders.
Maybe I'll check a dealer.

I've seen the listing for the KS USA office, think it's somewhere in PA or DE. It's on their website, sorry I don't recall exactly where, I'll look later this afternoon.
The oversize pistons are probably a dealer special order item but I doubt you find anyone who has ever done it. Besides the oversize they are talking about are just that, 95.05 over etc. nothing close to 3 or 4mms over, not intended for displacement increase but replacement for out of spec cylinders that are refinished.

Anthony

Anthony. I was thinking the same thing about the Oversized pistons.
If sold at a reasonable price they would be a great option for those that have cylinders worn beyond specifications as that is what they would be intended for. Even within the specificaions for standard there is a range of acceptable tollerance for "new" pistons and cylinders.

I just pulled my little spec. book. It shows the ranges for standard size "0" and 3 larger sizes. If I am interpreting this properly they are either oversized "sets" or specifications for boring oversize with the oversized pistons. Would they sell oversized cylinders since you can bore them out?
I don't think they are tollerance groups (Like weight groups.)

Based on my measurements my pistons fall into the largest #3 group.
I kept my sheet with my measurements but at the time I don't think I paid too much attention to the #3 size although I circled it in my spec. book.
I was more concerned with the clearance between the piston and cylinder which turned out to be fine.

So, I am the owner of an oversized set or oversized pistons with the cylinders bored out.

Some fine work all of you have done here. Outstanding job finding the truths to the Alusil debate. http://www.pelicanparts.com/support/smileys/clap.gif

You guys rock. http://www.pelicanparts.com/support/smileys/pray.gif Rock on!

Well, today I've had my old Alusils in to work. There we have a "Surtronic Talisurf" (as our Goetze technical man described it), otherwise known as a surface finish testor. We tested the surface finish of all 6 bores in varying positions. My engine has covered approx 80000 miles.

Depending on position within the bore, my cylinders measured between 0.49 & 0.60 mu.m RA. The area outside the ring reversal point ie below the bottom of the ring running area, measured a consistent 0.80mu.m RA, suggesting this is the factory standard RA.

My technical colleague, who I should point out is Federal Mogul Europe (Goetze) Aftermarket cylinder products technical boffin, conducted the test and pointed out the industry standard is 0.5-1.2 mu.m RA for newly finished cylinders. On this basis he says there would be absolutely no problem using Goetze phosphated cast iron rings, certainly on my bores. He pointed out chrome plated rings would *never* seal on such a surface, but Goetze have never offered these as 911 replacement parts. He also pointed out no harm in removing the chemical glaze which builds up on the bores, as a by-product of the combustion process, providing the cleaning agent used was not likely to harm the cylinders (parts washer?!!).

I'm still waiting for my Euro pistons/Nikasil barrels to arrive, which have supposedly covered similar mileage, so I'll do the same test when I get these.

Nathan....
Very informative post. Thank you!
And it looks like another nod in the direction of the BFPW (ala: JW).

Good post Nathan. Outside of ring mfgs, who would have such equipment ? I'd love to get more data for higher mileage etc. Maybe we could come up with some general rules of thumb for X miles then expect Y wear. (given no extreme circumstances)

William, I think the piston oversizes in the tech specs are both the standard for oversize and tolerance groups. We need someone with access to Porsche factory parts fiche to look up what is/was avail. for pistons.
I find it strange that Mahle makes so many combinations and KS only std. bore...

I think the surface finish tester was one of the machines my neighbor's
guy mentioned along with the "Comparitor" I tried that link but it didn't work. I would think the electron microscope would certainly see the variation, will it measure it?

anh911: Your last statement, can you expand?

All good machine shops should have surface finish testers. Certainly most of our big engine rebuilding customers in the UK do.

Sure William. I just meant that it seems strange that KS would only supply standard replacement sizes and not offer oversize. I can understand if they don't offer overbore "kits" if they aren't in that business but still. I guess we are lucky that Mahle makes the big kits. It would be nice if there were more options - prices might be a little less astronomical with some competition.

Adam (Rondinone) should have the cylinder...FedEx delivered it yesterday.

I sure do. It's much shinier than all six of mine (115k), indicating that it's pretty worn. Of course that just makes it a better test subject. Buffing an in-spec cylinder would get us nowhere. I'll get started on it this weekend.

I also have a surface tester, but we call it a profilometer. This one's accurate to a few angstoms in Z, and about 1 micron in X,Y. I'll run several important areas of Jerry's cylinder through it as soon as possible. As for the electron microscope, it's very accurate, with the added benefit of distinguishing ring material from cylinder material. The unfortunate aspect of the EM is that we can't look at an intact cylinder, which is why Jerry's our hero for providing the test subject.

I'm glad to read that information about the average surface roughness and industry standard. That's just the kind of information we need. Basically your expert is saying that with 60% roughness remaining, the new rings will seat fine. I really like the idea of defining a standard for cylinder re-use.

In the interest of cost, expediency, and availability, I've decided to finish hone, or buff, or whatever we should call it, using a quarz-based polish rather than getting the Sunnen AN-30. Although I can get the AN-30, it may take a while and the winter won't last forever (It took Sunnen almost a day just to get me a price quote). 3M makes a paint cutting polish with about 40% quartz powder in oil (The AN-30 is 50% silicon powder in oil.). Quartz has a hardness very close to silicon (Mohs 7). I can get the 3M product locally at Pep Boys. If the 3M product fails then I'll go ahead and get the AN-30. I'll do the physical polishing with an engine hone and some felt pads.

Since this is a group project, I'll leave this discussion open for the night, and if you guys object to the 3M switcharoo then I'll get the AN-30, with the understanding that it may be a few weeks before we have some meaningful results.

Rondinone,

Are you also going to test a cylinder that has been washed in a over the counter degreaser or parts washer?

see next msg

For the record, that cylinder is about 222K miles old.

http://forums.pelicanparts.com/uploa...1074218886.jpg

Note on the before flex hone operation the very sharp peaks on the graph. THese are the ones that the rings have to wear down during break in.

The second graph, after flex honing shows the shorp peaks removed and all remaining are closer to the same level or plateau.

A worn cylinder should have close to the same thing as the flex honed one if it broke in properly and materials used are good quality (leaves out most english stuff) Quality rings are all pre lapped now days so they should seat without any diffilculty to a worn cylinder iif sufficient cross hatch is present. The grit in a flex hone or silicone paste or whatever is used to re establish the surface is all that should be needed to do this if the cylinder is worn past the cross hatch. On the other hand a GOOD cylinder will always have cross hatch remaining, so the honing operation is just to clean things up a bit and add a few extra grooves for holding oil. If the cross hatch dissapeared I think it means the material is poor and or the engine never broke in properly and consequently no oil retaining grooves remained, allowing for significant wear to take place.