Goetze rings: #08-320900-10 (number on the box)
95X1.5 + 1.75 + 3.5 mm std.
These are the actual ring dimensions 95mm top ring 1.5mm middle 1.75 bottom 3.5.
The label also say's 911SC 3.0/3.2

That's what's in there.

William,

Thanks for that info.

My part # is a bit different (GOETZE 08-32000-10) but it does say for '78 to 79SC.

Measurements for the rings are also different.
1.5 / 1.75 / 4.0 ?

What year is your car?

OK, mine is a Euro 83, but has the US 930/16 3.0 engine. 9.3:1 CR

I've got the Goetze catalogue here...

08-320000-10 for 3.0L for up to July 1980 (4.0mm oil ring)
08-320900-10 for 3.0/3.2L August 1980 onwards (3.5mm oil ring)

I doesn't specify different rings for different Cylinder types does it?
Mahle / KS Alusil

No, as mentioned in a previous post, these rings are suitable for both, and the (single) Goetze part number interchanges to both Porsche OE numbers for Nikasil / Alusil. I've also confirmed this with the guy who designs the Goetze rings - he sits in the same office as me!!

Now, that adds some credibility to the discussion!
What is his / their imput on the topic?
Any testing done or aftermarket research?

After reading alot of comments (especially from Superman and Big John Walker) on Alusil's I decided to re-ring. My budget was limited and I had managed to break two of the old rings in my own d@*& fault type of a way. The rings did not fully seat for about 5K miles. I only have smoke on start-up now when there is more than 50% of the oil fill range on the dipstick. And the smoke goes away quickly. Everything was nicely in spec and the motor only had about 100K.

David,

Did you break the fresh motor in slowly or aggresivly? Im just curious since you say you have smoke on start up.

I'm in the exact same boat. Compression varies by 3% for all cylinders, but valve guides are worn. I've decided not to rering as I only put 4-5k on the car each year. Plus, as some on this board have mentioned, why mess with something that's not broken? If I have to tear it down again in the future because the rings wear out, so be it.

Just my $0.02. Good luck,

sounds like you need new valve guides and or valve seals. Did you renew them?

Also as I have previously stated, if you use a grape stype silicone hone on the cylinders you will see break in within minutes, not thousands of miles. Break in is always done with agressive, ie several full throttle accellerations and decellerations, followed by cautious driving for a thousand miles or so. This is necessary to seat the rings properly. The real key to breakin, besides the initial full throttle stuff is NEVER to let the temperature to get to high, no matter what. If the temps ok the engines ok.

Simon,

Aggressive break-in.

Jack,

I renewed the guides and seals. Could be I will find that is an issue when I take it down again to replace the new front seal that has already failed, probably self inflicted also...

David,

Did you use protection on the valve stems (valve rubbers) when you installed them?

These are the little capsuel shaped things the cover the grooves in the valve stem and protect the seals when the valves are installed. Not using them can cause the problem.

The problem being seeing smoke at start up or after sitting for a while. The smoke quickly goes away. This is a result of oil leaking down the valve stems when the engine is just sitting there. When the engine is first started and for a short while later the oil is burned and hence smoke. The smoke does not continue because the leak is to slow. Why worry?? Generally not to much of a problem but with high performance engines it may cause detonation, and consequently poor performance or if there is no knock detector, damage to the engine.

Goetze. In all my boastful descriptions of my successful Alusil re-ring job, I may have neglected to mention that I could see no visible cross-hatching in the cylinder. Again, wear was no more than .0015" and the cylinders were scrubbed/cleaned within an inch of their lives, and very little oil was used on the cylinder walls. One guy even recommended dry cylinder walls. This would probably cause the rings to seat for sure. The question is whether any rings would be broken in the process.

Jim is on to something here.
I don't think new Alusil cylinders are honed at all.
I suspect the silicon matrix is very thin, and honing will destroy it.
The Factory manual does not indicate honing Alusil cylinders is an option.

The set I removed from my engine had no cross-hatch marks. Even the area at the bottom where the rings don't touch, was the same way.

Until a bona fide expert posts here saying honing (with a "grape" hone, or whatever) is ok, I would either re-ring them as Jim did with his in-spec cyls, or have them re-plated with Nikasil.

What are used Alusil's worth? I'm doing a rebuild and picked up new P&C but still have my old. What are they in the board's estimation? I'm not going to give them away because they are a great teaching aid for my son for when he get's older on how engines work but if they had value, then I could always apply that money to something else I'm going to need like 8 x 16 rims. Thoughts? I saw a while back that Unclezak (sp?) got like $360 for his. I intend to put them up for sale on the board if people think they have value and if not, put them in a box and show my son when he get's old enough to question. He's two now so I'm thinking it will be a couple of years.

I replaced my Alusils with Mahles, and so, was planning to sell them. However, I'm now going to have them re & re'd with Nikasil first.

The cross hatch marks are extreemly important as they hold the oil that the rings ride on. No cross hatch, no lube, short life and lack of performance. Use an MG engine as the ultimate example of a useless engine block. The cross hatch pattern is there to begin with but they go away within a few thousand miles, due to the crappy metal the brits used, and the engine is due to be rebuilt within 30k miles.

I guarentee all of your cylinders had or have cross hatch patterns in them. If they do not the cylinders are worn past their usefull life. The pattern is put in there by the honing process, a necessary and essencitial step in producing ANY cylinder for an auto engine. Any special treatments, such as the silicone hardening still include the cross hatch pattern, because if it did not the rings would not have lubricaiton. If the original treatment, over 0.5 thousands of an inch deep, is still there, the silicone ball hone, which will not remove anymore than 0.05 thousands, or so, will not hurt it, but it will clean up the surface and put some additional, fresh grooves in the surface for the rings to seat to and to provide lubrication.

Again, honing, with stones, removes a lot of material, eg, with rough stones, several thousands of an inch, with medium stones, up to one or two thousands of an inch, with fine stones, up to one half to one thousands of an inch, and with plateau honing, less than 0.1thousands of an inch. Grape ball type hones are a plauteau hone type of process, a clean up of the junk metal, a final placement of grooves in the cylinder walls. These things are one of the "SECRET" ingrediants of NASCAR and other true racing engines. These are the things that are only recently being incorperated into producion engines, for smog reasons of course, but are the ones responsible for some of the very high performance numbers you are seeing now. They are NOT new however, racers have been using them for years.

If you want genuine Expert advise on these type of hones, talk to the company that makes them. THese people have dedicated their LIVES and LIVELYHOOD to KNOWING what their product does and does not do. They are engineers and have real test data to support their claims.

I have information here from KS regarding final honing of Alusil cylinders -"The honing process is carried out on a Sunnen CK10 honing machine. The first 3 stages (rough hone, finish hone, polish) are performed using different honing stones. The honing stones, oil and machine settings are all important for good results and are different for each type of cylinder (911,944 etc). The fourth and last stage is silicon lapping. Here the honing stones are replaced with felt pads. Silicon paste is applied to both the cylinder bore and the felt pads. No honing oil is used. The use of felt pads with silicon paste does not result in a measurable material removal. Silicon crystals are exposed by this process in the cylinder bore which results in a durable, wear resistant cylinder surface."

For the record, my (80k) motor has visible cross-hatch patterns in the bores.

Thank you, Nat!
A post worth printing out.

I'm still curious why I could not see any honing marks in my old Alusils.
Maybe they were just worn out, even though they measured ok (?)

Nathan, some more great info!
Does the felt pad or the silicon paste have any grit it?
I'm thinking like jewlers rouge.

I found the following PDF that has great information about Alusil Specific re-conditioning for this type of cylinder. It seems that this is a official MSI Motors/Kolbenschmidt document. The manufacturer says that they can be re-conditioned but Im sure tolerances still have to be within specs.

http://www.msi-motor-service.com/download/broschueren/alu_en.pdf

They mention that durring the felt process (final) that there is silicone polishing paste and no honing oil used.

William, with regards to our Goetze ring man, he suggests to go ahead and re-ring on the basis that in his 16 year history with the company, he can never recall any warranty issues on 911 rings (and our customers generally will try and find any excuse to claim for warranty work!) He said the phosphating will help assist initial seating, and the 911 Goetze ring is therefore suitable for all cylinder types. I mentioned in a previous post, the Goetze ring sells in excess of 5000 units per year (in European Aftermarket) with no warranty issues. Draw your own conclusions...

smestas,

That brochure is for retrofitting iron sleeves into aluminum blocks, not for honing alusil directly.


For anybody that cares,

Asusil, or any other hypereutectic alloy, is etched, not honed, at the factory. This is well documented. The reason it's etched is because the aluminum is easy to etch, and too soft to hone without galling on the microscopic level. By etching back the aluminum the silicon particles are exposed and they become the primary wear surface.

Hypereutectic alloys have been used for air cooled engine cylinders for 4 decades, including aircraft. For those of you with access to a university library, there are tons of references to the characteristics and performance of various types of silicon-aluminum alloy. I'd be happy to provide you with a few.

Rondinone,

Did you download or read the PDF link that I posted above? The whole document is Alusil specific from Kolbenschmidt. They even have specs in there for 944's and other PORSCHE models. The entire document is all Alusil specific.

I've deleted my previous post of page 8 of the document so not to confuse others by the images and actualy getting them to read the information.

Note the last honing operation, with the felt pad. It is exactly the same as using the silicone balls for the final hone. Both are considered plateau honing operations. Neither remove any real metal. THe honing operation I have been recommending is the same as the last step, even if the cylinder liners are not replaced. Again it places a new set of grooves to seat the new rings with, and removes any old extranious metal from the old rings.

The other honing operations are nothin SPECIAL. I have use the Sunnin hone as well as other hones for all the operations. You can even use a hand drill!!! (With suitable skills) I would not recommend the other steps to non skilled people, but the last step, the one with the grape style hone is a no brainer, no skill step. IF you can operate a drill you can do it, sucessfully.

For all the shops that do customers engines, try it, its only 80 bucks or so for the hones, use it on one of your race enignes first, if you do not beleive. You will very soon change your minds if you do. Have you ever fired up an engiine, and HEARD it break in withing 5 minutes??? Thats what these things do.

Nathan, thanks again for more info.
Simon, I noticed on page 8 of the document:

"The fourth and last machining phase is silicon lapping. In this process, the honing stones are replaced by felt pads. The cylinder bore and felt pads are coated with silicon polishing paste. Honing oil is not used. The felt pads and the silicon paste do not effect a measurable material removal. With this machining step, the silicon crystals in the cylinder block are exposed, which leads to a more durable and wear-resistant cylinder surface. An additional long lifetime can be expected from an aluminum cylinder block reconditioned in this way."

I'm not clear that this would be the same procedure our cylinders that have been in use. (I think the statement refers to the whole process which is the installation of new cylinder liners.

This partly answered my question. The paste is a type of polish.
Sunnen No. AN-30 KS Art. No. 50 009 859
Is this paste avalible?

It is not clear to me if the silicon crystals are impregnated just on the surface or thruout the casting. It does however state that it can be bored. So maybe the crystals are throughout the casting.

I also noticed that in the tables it lists at the bottom the Roughness RT.
The final polishing stone gets it to approx 0.6-0.8 my and the Silicon lapping actually makes it rougher (approx. 1-2 my)
What's a "my"?

All of this mounts more evidence that KS cylinders can and are reconditioned sucessfully.
Someone above (I can't see now while I am wirting this reply) asked for
a poll of who has done it sucessfully and who has failed re-ringing Alusil cylinders. So far I have only seen evidence to support it.

Yes I read it. I stumbled upon that document months ago while trying to decide what to do with my own engine. And it is about retrofitting alusil blocks. There's a picture of a guy sliding a liner into a block using dry ice to shrink the liner.

I'm not trying to be a jerk. I just don't want to see anybody foul up their engines by trying to do something that is universally recognized as risky. There's a conventional wisdom here that is being discarded.

I think we're trying to decide if it is 'conventional wisdom' or just standard practice that is justified for a professional builder, but overkill for the do-it-yourselfer.

The fact that not re-using alusil always works does not mean that re-using them will not work.

I just posted the question on the Contact Us link on the KS site.
Hopefully they will respond.

FWIW, I believe Rondinone. His description of aluminum etching instead of honing squares with my previous understanding. This exposes the silicon. Again, I knew this. Also, my cylinders and Doug's cylinders do not have hone marks, even in the skirt area where wear could not possibly have occurred. And finally, I believe that the thorough cleaning of my (in-spec) cylinders made my re-ring strategy successful, by re-exposing the etched surface. I continue to believe (and report to you) that my cylinder walls changed color and texture in JW's BFPW (large parts washer).

Fascinating discussion, though.

Alusils and re-etching chemicals
 

All,
I've red with much interest as one day I too wil have to deal with a broken head stud...knock on wood...it hasn't happened yet. Anyway, as far as etching is concerned. I used to use a motorcycle gas tank sealing product that cmae with an etching chemical. Applying this liquid to the inside of the tank (and ANY aluminum surface for that matter) instantly chnaged the color from a bright semi-polished look to a very dull, dark grey. Not only was the coclor changed, but as Superman pointed out after his parts were run the the BFPW, the surface seemed a bit...how would I put this...porus? Not a sllick, shiny surface, but a very high friction surface almost like comparing a super nice, fully waxed paint job to a flat finish paint. Do you suppose instead of taking the grape hone (which seems reasonable enough...with the intent of not causing the surface to gall), to the cylinder, the in-spec cylinder can be re-etched with the chemical to expose fresch silicon particles on the surface?
R/
Dustin

I completely believe that they can be reused, as evidenced by some people on this board. There's just no guarantee of success. But I also believe that attempting to hone alusil will lower your chances of success. This stuff was not designed to be honed.

The crystals are dispersed throughout the casting. Alusil is made by dissolving elemental silicon into molten aluminum. Like sugar in water, the silicon is more soluble at higher temperature. The silicon/aluminum melt is injected into the cast. As it cools, the solubility of the silicon decreases and tiny silicon crystals form. These crystals may make up 10-20% of the volume of the cast. The cast can be machined, but the final step to prepare the cylinder wall is an etching that eats back the aluminum and exposes silicon crystals, which become the wear surface. Think of it like a diamond tile saw. The exposed diamonds, which are visible, are the actual wear surface. The steel blade just hold the diamonds.

Believe it or not, alusil is actually more expensive to make because it's so difficult to machine. Even today engineers are trying to develop better tooling because conventional tooling doesn't last very long. Also, the rate at which the casts are cooled define the silicon particle size. So the casts have to be carefully cooled. We tend to think of alusil as a has-been material, but it's of great interest to the rest of the industrial world. It's still actively researched. I see a couple of papers a year on various silicon-aluminum alloys.

Personally, I've always suspected that alusil could be re-etched by the home mechanic. It's not difficult because there are commercial solutions (for semiconductor manufacturing) for etching aluminum at very controlled rates. I was going to try this on my own car if I ever needed to re-ring.

I should add that the cylinders should be really clean first. Otherwise the etch might not be consistent.

I bet Superman did unintentionally etch his cylinders. I'm not sure how, but I've been meaning to look into the formulations used in those parts washer solutions to see if anything makes sense. If I find anything I'll post it.

Rondinone et al,
Being new, I'm at a loss to understand why it seems like such a crap shoot to re-ring alusils? I mean, they had to have a fresh set of rings from the factory at some point, obviously. Is the gamble coming from the fact that the embedded material from the rings, blow by gasses, carbon and all the other nasty stuff an engine produces sufficiently "seals" the surface thereby making the success of a re-ring that much more difficult? As pointed out by some folks, a thorough cleaning and re-etching seems to increase the chances of a successful re-ring...dare I say in the realm of the original rings? Heck, I may pop off my barrels to find Nikasils (yea!) but still find this whole subject very intriguing. I really like the idea of a controlled etching (my motorcycle tank example seemed very extreme), and will probably give this a go if the P&C's are in spec. Really, for the cost of an in-spec, used set of Alusil P&C's, it seems like it's worth enough to experiment with them...

R/
Dustin

When I took my cylinders out they were very glazed and polished looking on the insides. After washing them myself with degreaser the insides became very dull/dry in finish much like what I imagine SUPERMANS were like. Im going to be running with them this way. Ive also contemplated giving them a few rubs with a scotch brite pad. What do you think?

Where are all the folks who have had a Alusil Re-Ring job go bad?

I don't know if I missed something or not, but what about nikasil plating the alusils back into spec and match hone them with a set of new pistons? I've done this for a few customers and have even repaired NLA 356 cylinders in this fashion.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

Charles,
I think what you may be missing is the cost factor. EBS quoted me around $1800 to do the procedure you mention (MUCh cheaper than new, and makes for a great alternative). If old, in-spec Alusils can be re-used for next to nothing, it makes for an even more attarctive alternative for dudes on budgets. Truthfully, I'd like to think I'd fork over the $$$ for either a new set of P&C's (or at least a set of replated P&C's), but I can't say I will have the same fortitude when it actually comes time to bust out the debit card...
R/
Dustin

Excellent thread!
Especially appreciate Rondinone's description of the Alusil structure.
Makes me think I'd like to volunteer one of my old Alusil jugs for a re-etching test. If they can be restored this way, I'd think it would be less expensive than having them plated with Nikasil.

I still think Jim (Superman) is right on the renovation of Alusil cylinders.
As he pointed out, John Walker used a powerful parts washer to clean the cyls. Note, he did *not* use any sort of hone, grape or otherwise.
In John We Trust.

Yup, when it comes to opening the wallet, with these engines you have to go wide wide open :-). If I'm not mistaken, my platers will re-do a set of alusils --> nikasil for under $1200 and they give a lifetime warranty on the work. I'm not sure if the price that EBS is quoting includes new pistons and rings, but if it did, that would explain the discrepency to my satisfaction. I have been using them for all my CNC billet aluminum cylinders for almost 3 years now and have not had one cylinder go bad to this day. There have been blems in the plating from time to time, but that's what my QC checks are for...

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance