Re-ring Alusils?

[911 tweaks]

bump...anything new??

[Porsche_monkey]

I'm hoping to hear from Rondinone sometime soon. He will be able to report on the surface finish of a 'worn' vs. 'treated' cylinder.

Adam?

[anh911]

Originally posted by Bobboloo
That logic makes more sense when your talking about other types of P+Cs' but not necessarily Alusil sets, hence this long thread.

If you've got a broken ring in an an otherwise good Alusil P+C set then obviously you've got no other choice if you want to reuse them.

My thoughts are that if your rings or pistons are near the end of their life with an Alusil set then your cylinders are probably goners and just good for cores anyway in which case I would bore them out and have them Nickasil plated and buy new pistons and rings.

The point of this thread was to prove or disprove the "accepted wisdom" at the time that Alusil cylinders couldn't be re-ringed. It has been proven time and again that yes, they can, IF properly prepared. Nowhere in this thread will you find knowledgable contributors SPECULATING on what type of rebuild work is required based solely on if you have alusil or not.
The condition of the engine/parts should be determined at every point before and during the process. Unfortunately planning for a 911 rebuild is tricky, (please note that I said rebuild - if you only need valve guides at 60K then this probably doesn't apply) You could have a good running engine and discover out of spec parts that will blow your budget. Hope for the best based on what you KNOW (data from compression and leak down tests as well as oil consumption, mileage, history etc) and prepare (financially and time) for the worst.

[anh911]

Originally posted by DohertyCM
Got it Ring part number ANH911 and clean up with the little ball hone..

I guess that saved me some money....if you look at it that way..

Hi, sorry for the late reply but I missed the reference to "the little ball hone" in your post. Please understand that as far as I am concerned this is NOT the correct way to refinsh your cylinders. Please spend some more time reviewing the thread before you do this. The correct method, as developed by the same people that made the parts in the first place (KS), is with an-30 and felt "stones".

cheers and good luck with the project.

[anh911]

BTW, if anyone out there has a set of out of spec 3.2 cylinders I'd be interested in them. PM or email me, thx.

[snowman]

THose little ball hones do EXACTLY the same thing the crap Sunnin came up with to avoid a patent fight.

[mike95125]

Have we proved this yet?

[snowman]

I don't think so. Someone dropped the ball way back and never completed this step.

[gabenheimer]

Oh my God! I just spent the better part of three hours reading this thread. It's like the sopranos, it just ended without any resolution. What ever happened to the reconditioned cylinder from the Canadian guy? Can we still test the ball hone technique?

I have an '87 Carrera with Alusil cylinders. The number two cylinder has significant scoring and I was about to toss everything and go to Nikasil until I read this thread.

Randy

[mike95125]

You can still recondition the alusil cylinders, that has been resolved. I have had all of my alusil cylinders reconditioned by Motor Works in National City, CA for about $190 3 years ago. If it is scored you would likely be better off finding a good used replacement and having it reconditioned. Just make sure it is in the same size class and you should be fine.

As for the ball hone, we are still waiting on the empirical evidence.

[Porsche_monkey]

I guess the 'scientific experiment' is dead. I sent a 'fellow Pelican' a 'used' cylinder which he measured the surface finish of. Then he mailed it back to me and I had it 'polished' on the Sunnen machine.

I mailed it back to him ( a loooong time ago). And that's where it ended. I haven't heard back from him.

Maybe it dragged on too long and he lost interest? I'm really frustrated that I spent the time and money, all for nothing at this point.

[DohertyCM]

Yes you can use the "dingle balls" (thats what I called them...) on the cylinders. Not long though- 13 seconds someone told me once....comes to mind but im not sure...so dont quote me...
But my mechanic does it and has a good track record with success as long as they dont use some type of synthetic super lube or treatment in the begining to allow the rings to seat properly...just in the beginning though.

I think its kind of like the 2.7 liter motor question....In the beginning there were all kind of problems so it was deemed to be bad...but since education came into play, and people started taking note and correcting and preventing the problems before they occur its turning out to be a really good reliable motor.
Same goes with these types of cylinders. As long as you know what you are doing and do it with the right tools you will be fine and have a pleasant experince.

People are always sure to blame the mechanical portion of the problem, before they blame themselves....

Wow I think i just came up with a good signature line!

[mike95125]

Still, the only data we have on this method is anecdotal. We were hoping to get empirical data that would be harder to refute. So far we have such for the Sunnen method only (IIRC).

[Eagledriver]

It would seem that the reconditioning of the cylinders is not only possible but the process doesn't seem to be that critical. There has been success with everything from the Sunnen method to scotchbrite by hand. With a few dishwasher only reconditions thrown in for good measure. I just did a re-ring myself for my race car and so far so good. Mine was not that great of a candidate because the pistons fit looser than the proper spec. I had the piston skirts coated to take up the clearance so I'm hopeful that they will continue to work. If they don't I won't be blaming the alusil cylinders however because of the piston clearance issue.

-Andy

[gtihop]

I did mine about 3000 miles ago. So far it seems ok. No oil burning as of yet. Time will tell.

[LWJ]

What an excellent thread! I read the first 14 pages or so until I realized I had burned over an hour at work.

Here are a few quick thoughts, which may have been covered in pages 15-26.

1) BMW's nikasil failures (530 and 540 engines) are attributed to sulfer in the fuel and fuel injectors spraying on the cylinder wall. My opinion is that it is possible that a high pressure stream could erode the thin plating of the nikasil. Of course, the Bimmer guys think Alusil is the "good stuff."

2) I worked in an Aluminum factory a few years ago. We made some bicycles and a few other products with what was called "metal matrix composite." This was an aluminum alloy that had a very high ratio of silicon in it, similar to Alusil. My recollections of conversations with the metalurgist is that the silicon was part of a "solid solution."

3) As the silicon is integral to the substructure of the Aluminum, it is not inconceivable that a chemical etch could do an excellent job "honing" the cylinder, as referenced by the poster who had his washed in a BFPW. Aluminum is highly reactive. It will react to both acid and base PH solutions. The great news is that the silicon should be left in place (which is desired) and the aluminum could be microscopically etched back.

I don't know if this thread has lost its momentum, but I wanted to give a plausible explanation for the BFPW theory.

Thanks!

Larry

[snowman]

It seems reasonable that any method that cleans up the surface and leaves space for oil to collect and do its job lubing and a hard wear surface, the silicone, for the rings to ride on would work. Chemical or mechanical should be ok as long as the surface isn't "ruined" in some way. My opinion is tHe silicon balls use the exact same kind fo material Sunnen uses in their paste. Both form a slurry, and both should wear the cylinder surface in the same way. I have been told that Patent issues prevented the use of the silicone balls by Sunnen.

Some shops claim that using the wrong method will cause problems and it takes a long time for them to show up. SO the bottom line, we still need more proof of what really works and what dosen't.

[FL911]

Originally Posted by Doug E

Doug - like many things in life the best laid plans go to waste ... when I got to the point of trying to pull the P's & C's together we couldn't get the wrist pin out simply by pulling on it. After a meeting of the minds (ie., 3 Pelicanheads/NoVa members who were in the garage with me) we decided to roll the dice and separate them. Worst case scenario I figured was that everything was OK and I could simply slide the P's back in using a ring compressor since with my Alusils I didn't want to install brand new rings.

In hindsight this made removing the wrist pins much easier b/c we used a 12 mm 1/4" deep socket on an extension and drove them out ... I don't see how anyone simply pulls those suckers out with how tight mine were in there.

After separation we closely inspected the rings and didn't find any damage. As of right now I'm going to clean the P's and then re-install them (same direction they were removed) using the same rings.

Thoughts / comments ?????

I could not agree more! Those wrist pins will not simply pull out....I did the same thing...had to seperate the pistons from the cylinders.

[Aurel]

The wrist pins will slide out freely if you heat the piston squirts with a propane torch. I wish I had known that before separating the P&Cs, since now I will be rolling the dice with new rings...

Aurel

[Eagledriver]

Just because you pulled the pistons out doesn't mean you have to re-ring. I've used old rings on 3 engines and new rings on one (all Alusil) and never had a problem. Not pulling the pistons and checking the condition of the rings is a mistake in my opinion.

-Andy