I believe they are cast as Aluminum Silicon alloy all the way through.

From all of the folks that I have spoken with, yes. Hypereutechtic (sp?) T-390 alloy. Alloy=all the way through.

yeah, but aren't they etched to make the surface mostly si?

I think that if you treat the freshly board out cylinders with one of the proven methods described in this thread then you would get the desired finish.

This thread has given me confidence to re-ring my Alusils but I have a question for the experts on the list. Goetze part number 08-320900-10 interchanges to both of the Porsche OE numbers for Nikasil/Alusil. But the factory spec book say the groove 3 piston rings for are different. For Nikasil "bevelled edge oil control ring with hose covered spring, not chrome plated." For Alusil "double bevelled oil control ring with hose covered spring, chrome plated." Is this a meaningful difference?

Hi zzwhm. I started this thread (what seems a lifetime ago!) and my Goetze rings are still going strong. I work for Goetze so had lots of help from our engineers at the time.. I've prob covered around 8-10000 miles since, and if I had to make the same decision again, I'd do the same...

I still have my alusil cylinders out for 'honing'. Then "ll send them back to Adam R for re-measuring the surface roughness. I'm embarrassed about how long this is taking.

Nathan M -
Thanks for the update. I plan to use Goetze and am glad to know that they are working great for you and so many others. But when I saw the difference in the Nikasil and Alusil oil rings described in the the Porsche spec book it made me wonder if it is meaningful. Maybe one of your engineers could comment on this?
Bill

They'd already confirmed they are suitable for both...

Yes, alusil cylinders are consistent all the way through the part. KS has another product - tradename, Lokasil - which is alloy all the way through but has a different mix of silicon localized at the cylinders.

Yes, you can overbore alusil cylinders, as William pointed out the problem lies in sourcing pistons. To be suitable the skirts need to be tin and iron plated. An engineer at KS suggested that perhaps graphite might work but hadn't tried. For 95 mm cylinders he said 98 mm was max overbore, any larger and the cylinder walls become too thin. Not sure what the max size would be for a 2.7. Best method is to overbore to another (alusil) stock or readily available replacement size if possible. Or you could find a plating company to treat JEs. The specs for the plating are in the thread.

I'm amazed this thread is still going strong. For those who haven't yet, please scan through it. There's a LOT, I mean really, tons of good info, hard work and research in here. Not to mention a little drama.

Well, I hate to report that after about 10,000 miles my engine outlasted the car. I wrecked it in November. The engine will be transplanted into an new test vehicle for further abuse! (Hopefully my brother's 73.5 longhood targa!)

My condolences. I am glad that you are seemingly ok.

Thanks, and this is am oppertunity. Next project is an 81 with a 3.6 conversion.

Measuring cylinders with electron microscope - only on Pelican!
 

What's the status on this? Not trying to get you to do anything, just curious if I missed it.
-Chris

I sent the cylinder back a few months ago.

Did you scan anything with the electron micorscope?
-Chris

I sent the cylinder for 'polishing' weeks ago. He keeps telling me it will be 'a few more days'. It will get done.

I will when I get it back. The EM can't see inside a cylinder, so I must break it up first. Those suckers are tough.

What has been the experiences of re-ringed alusil and the different honing methods. someone out there should have a few miles built up.
Thanks in advance

My cylinder is ready for pick-up. Within a few days I will mail it to Rondinone for examination. I can't believe how long this took...

I'm (still) on the edge of my seat!

Okay, more info. I picked up my 'repaired' cylinder from the rebuilder. He claims that he used this technique years ago as a factory authorized rebuilder for Vega engines, and (more importantly) for Orenda aircraft.

I don't think I've ever seen a brand new alusil cylinder so I can't comment on appearnce versus a new one, but it looks very clean with just the slightest cross-hatch visible. I'll post a picture shortly.

I'm going to mail this cyclinder back to Rindinone and hopefully he can move a little quicker than I did on getting this looked at. I'm anxious to see how close this cylinder is to 'factory'.

Hope this isn't too big....


http://forums.pelicanparts.com/uploa...1148929220.jpg

It has been a long time since I read through this thread.

Was this cylinder scrap and what technique has been used on it?

Yes he used chrome rings.

I think pages 14, 15 and 16 contain most the info you want...

I found the following information in Sunnen's book

http://forums.pelicanparts.com/uploa...1156536814.jpg http://forums.pelicanparts.com/uploa...1156536881.jpg

I just mailed a cylinder back to Rondinone that was 'honed' using the method shown by Snowman. He will inspect the surface and let us know if it's anywhere near the 12-18 microinches that Sunnen calls for. If it is in this range then I would say that re-using alusil is safe.

Hey PBH, was that the cylinder I sent you? I did send mine to you for treatment, didnt I?

It has been a while and I dont remenber who I sent it to ;) I am glad to see that we are keeping this thing going in our free time :D

Yes you sent it to me. It sat around my shop for a long time, then I mailed it to Adam to measure it before honing (I should have had you mail it to Adam directly), he measured it and mailed it back to me, it sat around here a while longer, then it sat around the engine rebuilders shop. Then it got lost in my shipping department. Then, finally it went back to Adam.

That cylinder has more miles on it then my 911.

Mine too:D

I have my 2.7 rebilt now and sitting in the car....and maybe some day it will run. The only things I need to adjust are fuel, air and spark :rolleyes:

Summary please
 

I went through this thread and now I have a headache...

My mechanic friend re-rings all the time. And he has never had any problems, BUT....

I dont go into his shop with out having some idea of what I am talking about.

SO>>>

We have established they can be re-ringed...

Now what rings do you use...part number?

Can you use JE Pistons with these cylinders?

I am at tear down point and need this answered please..

Re: Summary please
 

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..

Re: Summary please
 

Yes, the general concensus is they can be re-ringed.

Alusil cylinders are supposed to use ferrod coated pistons. JE pistons do not come that way. I don't even know if they can coated. Maybe someone can comment on that.

Question, are your pistons out of spec? I thought the ferrod coated pistons usually out last the alusil cylinders.

Question #2. Are your rings out of spec?

I'm probably alone on this but I wouldn't replace rings that were in spec on a set of pistons for Alusil cylinders. I don't see the gain. Breaking in a new set of rings would just put additional wear on a set of used cylinders.

How does a set of used iron plated alusil pistons look like? Isn't there a big chance the plating is worn off?

Bobby - you are definitely not alone in your opinion - I was told the same thing by Steve Weiner and some local rebuilders when I was doing a top end a few years ago. Mine were in spec (with 65k miles) and we put them back in, and so far so good.

I dont know yeat, I am just beginning the engine pull. But I was putting together a shopping list and figured heck if the heads are off why not do a re-ring and replace the rod bearings.

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.

Its sort of like this. If the cylinder is properly honed and holds oil properly, and is of a good material, it will simply not wear. The piston lands will wear, from the pounding up and down and no oil will prevent this. Eventually you need new pistons, but NOT new cylinders. A simple honing will restore the original depth of the oil grooves, microscopic, and your good to go for another 150K miles with new pistons.

A bigger problem is that pistons and cylinders are sold in sets, not individually. You can get them individually but the cost will probably be that of a complete set anyway, so as a practical matter, you get both, need it or not.

If your in business, you cannot use "used parts" just because you have no knowledge of their history, so back to full sets.