Re-ring Alusils?

[snowman]

Hasen't anyone just asked Porsche what they think? I would think their engineers would be able to respond to this question and an answer all could beleive would be made available to us.

[konish]

Charles,
You are correct in your assumption that EBS's price includes JE pistons, rings and the replate. Truthfully, I think this is the road I will choose, when time for the rebuild. However, I MAY just for experimentation, try and re-etch the cylinders and see what happens. Worst case is that after a few thousand miles, I'll have to spring for the reconditioned P&C's, and spend some time R&R'ing them. Best case is that they work great, and it will buy me an indefinite amount of time prior to buying new/reconditioned P&C's...maybe a year, maybe 10 years. In any case, at least the bottom end will be fresh and I won't have to worry about splitting the case...

R/
Dustin

[cnavarro]

If someone does find out how or where to recondition the alusils through an etching process (or another method, per manufacturers recommendations), I'd love to find out where, since I get emails fairly often asking about how to rebuild alusils. I would love to be able to give two options to my customers...

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

[Groesbeck Hurricane]

Jack,

The burn-off at start-up is only when the resevoir is filled with extra oil. When I keep the oil at about the 50% mark there is no burn-off. I remember reading threads here about slight seeping of oil when overfilled and a quick burn-off on start-up. Again, keeping at about the 50% mark, no smoke on starts. I installed the valves per the factory manuals and the Bentley, Waynes book was not available when the work was done.

Doug,

Like usually happens, I agree with you on advice to follow,

[William Miller]

Simon, I cleaned/polished my cylinders with a scotch brite pad wrapped arround a standard 3 arm hone. I did use oil. The finish was simular to what I saw at the bottom of the cylinder where the rings don't touch. About 30 seconds at the most and about 10-25 slow strokes up and down with the cordless drill.

This simple procedure worked for me. I've now got about 2500 miles on the rebuild and no smoke at all.
I was willing to take the risk. At that time we didn't have all this knowledge we are seeing here on the board. The info we saw from the cylinder manufacturer use of silicon paste and a felt pad is what I now believe would be the right way to go. Probably after the BFPW. Or at least a good cleaning with the same chemicals.
Anybody put theirs in the dishwasher?

[Superman]

This is indeed an excellent thread. I'm curious about where the guys are whose Alusil re-ring jobs failed. It's considered a crapshoot, but where are the failures? Also, JW's BFPW uses a solution that's supposed to be aluminum-friendly, so I doubt that it would have removed much metal. But it sure got them clean, and made the surface....well....not "rough," but it was different-colored and less smooth (the glaze of course had been removed). Again, cylinder taper was no more than .0015" (my motorhead friends called this wear "miniscule"), and the ring lands were also WELL within spec. I've got right at 50k miles on these new rings, and no problems whatsoever. I'm getting tired of checking oil level between oil changes. Nearly a waste of time.

[Doug Zielke]

Originally posted by William Miller
Anybody put theirs in the dishwasher?

If you mean, cylinders, no.
But I *did* put the cam towers in Mrs. Z's dishwasher.
The lumps on my head are almost gone now!

[William Miller]

Anybody seen the show Mythbusters?
This would be a good case except wouldn't get the ratings like blowing something up!
If it is a myth, I wonder who started it. Somebody must have had a bad experience with re-ringing.

With all the knowledge in the audience I wanted to ask what's so special about Nikasil? What or how is it made and why is it better as we are led to believe? What are the differenences in the 2 types?
It seems like a lot of Alusil cylinders are being reconditioned replated with Nikasil what is the process? Do they etch the Alusil in the process?
I've seen some dammaged Alusil Cylinders posted most of these don't seem to to have anything to do with the material the cylinder is made of.
There are probably a lot of Nikasil cylinders with the same dammage.

It also seems like the Alusils are wearing pretty well and alot of them are measuring withing the wear limits?

[konish]

Super,
I'm with you on this one. I'd love to know why...and maybe Jack is right about contacting Porsche...re-ringing Alusils is such a gamble..? Rondione offers some very compelling information on the formtaion of the casting itself and the fact the silicon particles isn't simply a "plating" but actually saturated within the aluminum structure itself (at least thats my understanding). From my VERY limited knowledge (okay, none really) it just seems logical that new particles can be re-exposed through an etching process, and the limiting factor is essentially the cylinder measurements. Perhaps all these years of folks saying it was a bad idea to re-ring Alusils really skewed the sample of folks that may have tried this process choosing instead to go with new P&C's(?)

R/
Dustin

[smestas]

Is this an opportunity to horde up all the orphaned Alusils and sell them for $$$$ once the myth is busted? I have seen previous threads saying that they are worth 10.00 which is a shame.

When the truth is exposed I will no longer hang my head down low with the thought of my cylinders. I will walk proud with my brethren and form the new 911 coalition ACR "Alusil Cylinder Renegades"

SCWDP, GuppeB, and Rgruppe beware! ACR is no longer walking in the shadows.

[Superman]

Indeed. Clean, re-etch and go. That would make Alusil cylinders nearly a "forever" cylinder....the opposite of its reputation. So, perhaps when lemmings throw their away.... When I was about four years old, I developed this irritating habit of asking "Why?" And I've never stopped.

[William Miller]

I assume at some point they will wear beyond the ovality specifications. Wouldn't it be possible to get them bored a hair oversized exposing a fresh surface. I would think EBS does this before plating with Nikasil.
They should be able to provide a "1 over" piston and ring set.
WHY? WHY NOT?

[Rondinone]

Konish,

I believe you hit the nail on the head. There is evidence that some of the ring material transfers to the cylinder wall during the initial wear stage.

Smestas,

I've been looking into degreaser formulations, and several contain alkoxides (i.e. butoxyethanol), which can be reactive with aluminum under the right conditions. I've seen a few commercial aqueous parts washer solutions that also contain alkoxides or alkoxide polymers. It's entirely likely that a degreaser available to a home mechanic would be reactive enough to etch. If I remember correctly, one would only need to etch a micron or two to expose fresh silicon.

Aluminum, good or bad, is highly reactive. That's one reason you shouldn't get bleche-white on your rims, because it will pit them quickly. Last year I bought some stainless steel cookware with aluminum handles, and the manufacturer forbids the use of lemon scented dishwasher detergent because it will eat up the aluminum.

Scotch brite pads, if nothing else, would insure that no part of the cylinder was left uncleaned and possibly unetched. Maybe the best thing for us alusilers to do is send our jugs to JW and have them run through the BFPW.

[smestas]

Originally posted by Rondinone
It's entirely likely that a degreaser available to a home mechanic would be reactive enough to etch. If I remember correctly, one would only need to etch a micron or two to expose fresh silicon.

You know now that you mention it I recall the back of the degreaser product (castrol degreaser/purple bottle) saying that prolonged exposure on aluminum parts can cause damage. So when I used it I was cautious to rinse my parts with water afterwards.

[snowman]

Ok guys,

Almost everyone pukes at the idea of running a grape style silicone bead hone down a cylinder (any kind) but no one says anything negative about ETCHING)!!!???

The grape style hone cannot remove any signigicant material, of any kind and is extreemly unlikely to damage any finish of any kind.

BUT ETCHING??!! Chemical etching, in an uncontrolled manner, no less, is a process that COULD ruin ANYTHING. ANy chemical that etches the cylinders is removing orders of magnitude more material than the grape style hone, and in a completely non understood manner.

Furthermore chemical etching will NOT leave the grooves NECESSARY for proper lubrication. If it works at all its a fluke, if real etching is happening, not just some slight change in appearence, which could be at an optical level, insignificant for mechanical considerations.

Its amazing to me that a practice, long accepted by racers (over 15 years), is poo pooed, but a completely unknown, unverified, and non supported by any engineers or scientists at any real company or racegroup anywhere would be considered to be possible better.

Sorry for the rant, but what can I say??

[snowman]

Originally posted by Groesbeck Hurricane
Jack,

The burn-off at start-up is only when the resevoir is filled with extra oil. When I keep the oil at about the 50% mark there is no burn-off. I remember reading threads here about slight seeping of oil when overfilled and a quick burn-off on start-up. Again, keeping at about the 50% mark, no smoke on starts. I installed the valves per the factory manuals and the Bentley, Waynes book was not available when the work was done.

Doug,

....

The source of the smoke is probably still the same, ie the valve guides. Maybe that the ammount of oil just overwhelms the guide seals, its possible. Not only that it is the only source for oil that burns off quickly, there isn't any other. Keep the oil at the proper level as the side effect of a little extra oil is a tendency to detonate early, which will either reduce performance (because the knock detector is retarding the timing) or engine damage because of the excess knocking ( maybe unheard, but still there).

I didn't remember seeing a response to the question about valve rubbers. Did you remember to use protection? If not damage to the valve seals is highly likely.

[konish]

Jack,
Yes, I'm a very junior member to this board, but I have lurked for years, and it seems your very own statement:

"Its amazing to me that a practice, long accepted by racers (over 15 years), is poo pooed, but a completely unknown, unverified, and non supported by any engineers or scientists at any real company or racegroup anywhere would be considered to be possible better."

Is the same kind of advice ALMOST everyone states about not being able to re-ring Alusils. It also seems to me that you stand in the minority of a lot of "conventional" ideas, which I don't think is bad at all...in fact, I think its refreshing. You have to admit, there seems to be more "expert" advice suggesting this is largely a crap shoot. Actually, I kind of like your idea about the grape hone to knock the ring material out of the pores of the cylinder walls, and I'm not sure anyone suggested etching in a completely uncontrolled manner. For me it comes down to wanting to explore other possibilities while looking at this problem in a quasi logical fashion, and this discussion is really starting to move outside the box a bit. The bottom line is that I have not heard anyone, expert or otherwise give me a definitive explanation why a controlled re-etch of the cylinder is not possible making a re-ring unlikely to work.

R/
Dustin

[konish]

Interesting...check this out...

http://frwilk.com/early944/cylinder.htm

R/
Dustin

[Rondinone]

snowman,

Remember that we're just talking about alusil here. Of course honing is the preferred method for most cylinders, but it is not generally accepted for alusil because it doesn't work as expected. This has been demonstrated, and is also stated by Porsche. The simple fact of the matter is that if honing worked, this thread wouldn't exist.

>Its amazing to me that a practice, long accepted by racers (over 15 >years), is poo pooed, but a completely unknown, unverified, and non >supported by any engineers or scientists at any real company or >racegroup anywhere would be considered to be possible better.

Actually, there at least 30 years worth of knowledge in the scientific and engineering literature on silicon-aluminum alloys. Like I said before, I'd be happy to provide references for those with access to a university library. Porsche didn't invent this stuff, they just employed it.

Your assertion about oil in the grooves is entirely correct. It's also true for these materials. But rather than linear grooves that honing would produce, these materials have more random voids left between the silicon particles from the etching. This is also in the engineering literature.

As a matter of reference, our understanding of etching from both chemical and electrochemical perspectives is very well defined. The semiconductor industry has developed routine methods for pure chemical etching submicron layers off aluminum films with exquisite control. And if we etch electrochemically, that is by applying and controlling a current that ionizes and removes metal atoms from the materials' surface, we can control the etching process right down to deciding which metals are removed and which are left behind.

But, have you ever looked at a cylinder wall with an electron microscope or a profilometer before and after honing? Of course not. This is not science. You don't know how deep the grooves are that are left behind by any hone, grape or otherwise, and I promise that they're all different anyway. What works in our favor is that the margin of acceptable parameters is huge. A surendipidous etching may work just fine. And for us alusilers, anything that works is better than where we are now.

One last point: the etching that is achieved by a degreaser or cleaner is going to orders of magnitude less aggressive than the etching achieved by acid, or bleche-white, or even tomato sauce. This is because degreasers are not acidic, they are generally basic. Furthermore certain ingredients like alkoxy alcohols are slightly reactive with the aluminum. And I made the offer before that if anyone wants to donate an old alusil jug for some etching experiments, I'd be happy to carry them out. I have access to all the equipment necessary to characterize the cylinder surface before and after treatment.

[William Miller]

Konish, I could not read the bottom of the page or scroll down where it was leading to the good part about what Porsche recommends. with the Sunnen Machine.
Jack, your idea is very simple and you say it's proven. It could be done by anyone sucessfully. I hope my scotch brite polish will last. If not I'll move on.
There's more than one way to skin a cat.
I'm still waiting to see if KS reply's to my e-mail.
Did anyone try porsche?