Re-ring Alusils?

[Rondinone]

Here's the polished region:



The round blob at the bottom (marked with a red 2) is a calcium carbonate particle. Calcium carbonate is added to motor oil to neutralize combustion acids.

It's obvious here that there is more texture. There's a silicon particle at the top left that is a little exposed. There is also significant pitting. Here's another:



You can see alot of debris here. Most of it is ring material. Some of it is leftover polish (the quartz abrasive). There are tons of pits and holes. Here's a zoom on a pit:

[Rondinone]

After having a look with the SEM, I put the pieces on my profilometer. My profilometer can also calculate the roughness (Ra), but all my numbers were lower than those posted above. Because the instruments are different, and mine's not set up specifically for testing cylinders, I wouldn't get bent out of shape about it. The relative numbers are what's important.

Factory finish: 0.26, 0.32, 0.17, 0.34. microns
Worn area: 0.095, 0.136, 0.12, 0.18 microns
Polished area: 0.37, 0.87, 0.40, 0.20, 0.13, 0.16, 0.31 microns

I took several measurements from different places.

Overall, the surface definately got rougher during the polish. A few things concerned me however:

1. There was alot of pitting. I know this cylinder has 220K miles, so I shouldn't be surprised. The pitting was visible to the naked eye (looks like darkness/roughness on the cylinder surface). I probably would not reuse a cylinder with pitting after seeing what it looks like at the microscale. Makes me feel better about getting those camshafts reground also!

2. I identified a bunch of leftover abrasive. It was everywhere, in pits, stuck to the surface, etc. Since so much is left over, I think that using the actual silicon abrasive (rather than silicon oxide, quartz, that is in the 3M polish) from Sunnen is probably better. There might be unexpected consequences of using quartz.

3. The polished surface looks nothing like the factory finish, due to the extensive pitting. But if we look past that, we can see improved relief of silicon particles (this was evident in profilometer also) in the polished area. Will that lead to improved ring break-in? It might.

This was only one experiment, and if I had to polish the cylinder again I would probably go longer. I didn't expect to see so much ring material left behind. It must really be lodged in there.

I didn't post all my photos, and the originals are much better quality (100k limit). I'm going to look all this over and think about it some more, and maybe even take another look in the SEM. I just learned that my own cylinders will need new rings. The compression was perfect across the board, but some of the ring gaps are too wide to warrant reuse.

[anh911]

Excellent information R, thanks. There might be some correllation to your ring gaps and the amount of ring material you found in those cylinders. The only way the gaps get big are if the ring wears or the cylinder does. (I know the cyl you are using for exp. isn't from your car) Can you measure one of the old rings' width to see how much it's worn? Seems like one key to a good job is getting most of the ring material off the cylinder surface.

[snowman]

Rondinone,

Is it possible to also post a macro view of the cylinder finish, one that shows the cross hatch that results from the circular and up and down movement of the polishing (honing) machine.

I realize this could be near impossible with the 100k limit. Possibly on someones web page?

[jstgermaine]

You can email me high res pics of whatever and I can post them.

My direct email is jstgermaine@stgassociates.com

[anh911]

Hey R, how about a shot of the BFH smashing process...

[Rondinone]

Ha! I didn't record it because I knew you guys didn't have the stomach. As I swung the hammer I had this wierd daymare about accidentally grabbing the wrong cylinder.

I've been pondering this tonight, and I think that the real important information here is not what is shown, but what isn't shown. We know that traditional honing stones rip up the alusil surface making the cylinder unusable. This procedure didn't do that. And the profile numbers show that the polished area is about twice as rough as the non-polished worn area, so aluminum between the particles was removed. I
am going to think a bit more about this, and possibly examine some other areas of the cylinder.

Snowman, I didn't see anything like honing marks on these pieces. There were some scratches on the silicon particles but nothing like what's in the brush research literature (I've got it also). However, when I take photos of the cylinder you're getting I will be able to post them.

[snowman]

Ron..e "Ha! I didn't record it because I knew you guys didn't have the stomach. As I swung the hammer I had this wierd daymare about accidentally grabbing the wrong cylinder."

Sort of like taking a sledge to a Porsche, any Porsche yuck!!! Now I can't sleep, or eat, worse than the nightmare on elm st or any Gilbert Godfrey fling

I almost "reported this post to the moderator" as being unfit for viewing.

[smestas]

Awesome information Rondinone!

My Alusil rebuild is awaiting the final results (parts washer/ etching) before I go any further.

Thanks for the hard work to bust the myth and for the great information. Long Live the Alusil Revolution.

[William Miller]

R, great work!
Someone above asked what Scotch Brite pad I used. It was the green pad without the sponge attached. Bought it at a grocery store. I used the same hone as R, but didn't wrap it, just sandiched it between the stone and the cylinder wall.
I know they make several different pads with different roughnesses.
I doubt it's the plastic balls because it definately scratches metal. When I clesn my stainles kitchen sink a new pat will certainly leave very fine scratches.

R, regarding the clogged up pores. The thought just came to mind that maybe the hone should be run in both directions. If the drill was reversed the particles in the compound might get in and clean some aeas that were not reached in the other direction.
How much ring material did you see in the worn cylinder. I sort of anticipated that the ring and piston material would be worn and deposited or clog up the pores.


Also good news about being able to plate pistons.

[Porsche_monkey]

I just had my cylinders done by the Sunnen method. Cross hatches are clearly visible. (I will email JSG pictures)

If someone wants to send me a cylinder I could have it done by the 'official method' and returned for inspection.

[jstgermaine]

PBH,

I can send you a cylinder from the same set Rondinone and snowman are experimenting with. When you email me the pics, send your shipping address along.

[William Miller]

PHB, where did you get them done? How much?

[Porsche_monkey]

I had a local (Toronto area) old-timer do them. He says he used to make a living doing Vega's 8 hours per day as he was the local expert and all the GM dealers brought their cars to him. He knew exactly how to do them as soon as he looked at them. He also does aircraft cylinders the same way.

He does them in about 5 minutes using the Sunnen method. He also did my heads and supplied new rings, and since I paid cash (guess why) I did not get a detailed bill. I believe he told me it was about $10 per cylinder (CDN funds), but I might be wrong.

I have received a LOT of help from this board over the past few years, I would be glad to have a cylinder done at my expense in return.

[William Miller]

Old-timer's the best! That's a relative term.
My brother is 10 years my senior, just hit 51. He was wondering at what age old fart status turns to dried-up-old-fart. I told him it might be closer than he thinks. It ain't just the age it's the milege!

[Porsche_monkey]

An 'old timer' is anyone ten years older than me.

[anh911]

A couple of thoughts have come to mind regarding the paste method. I noticed in the pic that it's labeled "fine" perhaps a more coarse variety (I'm assuming tht more coarse would mean larger particles of abrasive) would give us less of a polished finish and more the buff look we want. Also, wouldn't a wash-down with a good solvent after honing get rid of most of the left over polish? Finally, how about using a stiff sponge in place of the towels? The sponge would hold more of the paste. I recall one of the Sunnen or KS guides said to even apply honing oil while using the paste to aid the process.

[Porsche_monkey]

I believe Sunnen uses felt.

[anh911]

Sorry, I wasn't clear in that last post. I meant to address it specifically to how Rondinone was testing.

[KTL]

If you want to stick with the 3M stuff? They make all sorts:

3M Compound Products



For instance, on my car I used the microfinishing stuff, then the Perfect-It II, then the Imperial Hand Glaze (not pictured). All with a orbital waxer/polisher. Oh this was on the paint by the way.........

But my guess would be to try the microfinishing or ultrafinishing stuff for heavier cutting of the cyl. surface. Try the super duty stuff if you think it needs more? I was a bit leary using the microfinishing stuff on my paint, but it did a great job cutting thru the surface to expose fresher-looking and much brighter red paint. This is of course soft paint, not hard metal surfaces. Just saying that the microfinishing stuff has a pretty good cut to it.

You can get the stuff online if you can't source it locally.

HandsOnTools