do I need to hone this?

[350HP930]

Those diamond hones require a lot of pressure. What are you planning on driving those with?

[Henry Schmidt]

Originally posted by 350HP930
Those diamond hones require a lot of pressure. What are you planning on driving those with?

We will be using a Sunnen CV 616 Power hone with adjustable feed pressure.

[350HP930]

Thats a sweet machine. Do you all only do porsche work or do you guys work on other makes?

[Henry Schmidt]

Aircooled 911 based Porsche engines and transmissions only.
No water please!

[350HP930]

LOL, I just hope there is water based coolant/lubricant in your honing rig. I much prefer working with water based cutting fluids as compared to the oils.

[Henry Schmidt]

Originally posted by 350HP930
LOL, I just hope there is water based coolant/lubricant in your honing rig. I much prefer working with water based cutting fluids as compared to the oils.

Tree hungers in California make oil based coolant/lubricating products hard to work with.

By Water I meant "no water cooled cars."
Accept this one of coarse.

[William Miller]

Henry, last spring there was a long post on refurbishing / reusing Alusil Cylinders. Any comments?

I rebuilt my engine before reading any of this. The cylinders measured within specs. I used the green scotch brite you get at the grocery store.
I used a typical 3 stone hone. I wrapped the scotch brite inside the cylinder bore and inserted the hone which bassically added some consistant pressure to the pads. I did use light oil (Can't remember maybe just wd 40 to keep things clean). I ran the drill for 30-40 seconds with an up and down motion.

This was very easy. Unfortunately I had no good info on the process or a tool to measure the surface roughness. Maybe you can do some tests for us alusil guy's.

The results of the thred lead to a procedure used by sunnen with felt pads and paste.

If you have some time look it up. You may have been there already, I havent been on the board for a while.
Good luck on your quest for the truth! I'm behind you all the way!

BTW I've got about 5,000 on the rebuild. Rings seated fine and so far no smoke. Engine's out now because I'm now restoring the rest of the car.

[Porsche_monkey]

Bill: Your car does not smoke now, did it smoke before the rings seated? I just rebuilt my engine and I get few seconds of white smoke on start-up. I'm hoping it will go away with more mileage.

[William Miller]

Only for a minute or so, but I assumed it was assembly lube etc.
Then the only smoke was from main seal leak.
Only other smoke I've seen out of the tail pipe is from rich fuel at startup when it's cold.

[Porsche_monkey]

So, how can I tell if it's oil or rich?

[William Miller]

The smoke is whitish (Unburnt fuel from the cold start valve.), only when cold. I've read this rich. I've seen oil smoke is usually dark/black. Am I right? Disel is black smoke when rich.

[Porsche_monkey]

that makes me feel better so I will agree. I only have white smoke, and more so since I tweaked my WUR to factory settings.

[Jesset100]

This information is priceless!
I'm going to be rebuilding my engine in about 10,000 miles. Looking at prices for P\C @ Pelican Parts made my heart sink. Reading this thread though made me feel a whole lot better as well as my wallet. Henry you are amazing!

[Henry Schmidt]

Thank you guys for the kind words

Oil smoke is white / gray and rich running condition is black. If you've watched Formula One and seen an engine let go, the white plume of smoke is oil.
I was trying to think of a way to easily tell the difference but I am unable to articulate an easy way. If you have white smoke and no oil leaks, keep an eye on your oil level.

As for reringing Alusil, I have no good information about this because I don't do it. I will reuse a matched Alusil cylinder, piston, ring set if they look very nice and the ring gap is within tolerance but when the rings are worn I find another option.
It has been my experience that you will have a hard time finding any rings other that Factory ring from the dealer and they are so expensive that it's not much of an option. Many ring manufacturers ( Hastings, Total Seal and Deves) recommend the same rings for Biral, Nicasil and Alusil cylinders and that just can't be right.
Good luck

[William Miller]

Try Gotez and look up the Alusil Thread.

[Henry Schmidt]

Goetze does make them, but as far as I can tell no one but the dealer sells them. If you guys have another source let me know.

[ChrisBennet]

Henry,
Did you get a chance to do the diamond hone experiments?
-Chris

[aigel]

Henry, you did excellent work helping establish some guidelines for us cheapos that want to re-ring nikasils! If you see the piston rings being eaten up on the honed cylinders, it must be the case, so I am not going to argue with that. Your tests further support your observations. It is also great to see what Mahle specifies and delivers in their cylinders.

I have a few thoughts about roughness represented using Ra, and what that may mean for cylinder sidewalls and ring wear.

Note that you could get a huge average roughness, even if there is much flat area (plateau) and only concave scratches, no burrs or peaks. Here is an example (from http://www.predev.com/smg/parameters.htm#Ra%20-%20Average%20Roughness) These three profiles all have the same Ra number!



It is clear that if you have a surface like the first one or the last one in the figure, you'd wear the heck out of the rings. But if it were a surface like the one in the middle, with much plateau, it may not be bad on the rings at all, even though it has a high Ra value.

Now, I am not a machinist and can not predict what a ball hone will do to a very hard surface. I would just guess that there is little ductility in the material, so there may actually be little smear and more cutting, possibly resulting in a plateau type surface?

If anyone has access to a profilometer that can record the actual profile, I'd be real curious to see them measure Henry's test cylinders. And if you can supply one done with the Scotch brite method, we'd really be rolling! Of course, who's got that much time on their hand?

In the end we should count on Henry's experience over a measurement and theory anyway. Likely, by the time my engine comes apart at over 200k, (knock on wood!) I will have to buy new p&c anyway!

Cheers, George

[snowman]

I think Henry answered the question way back at he beginning. His experience showed that the rings wear out quickly when clean up is done with a flex hone. Its a little puzzeling though as the flex hone is supposed to plateau the surface.

[hcoles]

I was hoping that this thread would conclude with a "technical" description of the desired surface when re-ringing Nicasil cylinders with Gotez rings or another brand for that matter.

Has anyone asked Gotez if there is a written statement of surface condition or process they recommend for re-ringing?

I don't discount that processes or methods described in the thread could be correct or even better than what the e.g. Gotez people might say. It just seems like a position from Gotez would be available.

It seems reasonable that Wayne would be able to get an official statement from Gotez or find out that Gotez understands the question but will not give out written instructions for using their products.

If the Gotez info. is on the website, I apologize, please send me a pointer.

-Henry