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How to access cylinder wall condition?

1. Before honing?

2. And after honing?


Before honing, I have two cylinders one has:

A. Stains that appear to run part way down the wall. Is this a fuel glaze stain? Does this come out after honing? and then the other:

B. The other cylinder has spotty black colored pin tipped sized spots, that are smooth enough that I cannot catch a finger nail it them, but I'm wondering if this is a concern before, and then after honing?

I looked on the web and could not find any photos of cylinder wall diagnosis. I'm interested in visual accessment vs. micro-measuring in this instance.

Thanks
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Old 01-07-2005, 07:15 AM
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I assessed mine using a profilometer, which should be available in any good college chemistry department. But first, soak them in xylene or toluene the remove any oil. Pitting will be visually obvious without oil coating the wall.
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Old 01-07-2005, 07:23 PM
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I hate to say it, but in my book there should be no pitting in a cylinder. I am unsure what you mean with "stain". Anything that is not a defect should clean up with some steel wool and break parts cleaner.

The honing you will do, likely is with a ball hone and just to put a cross hatch pattern in the cylinder to assure proper ring seating? This is not going to take off any significant amount of material, nor will it cover the entire area evenly. There will be deeper and there will be shallower grooves. None of that will clean up pitting, unless it is very minor.

I'd clean the walls with a fine steel wool as good as you can and then give it a shot and see how they look after honing. Maybe you get lucky and it is minor enough to clean up. If it is still there after honing, get a set of replacement cylinders.

Hope this helps.

George
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Old 01-07-2005, 10:09 PM
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Quote:
Originally posted by aigel
I hate to say it, but in my book there should be no pitting in a cylinder. I am unsure what you mean with "stain". Anything that is not a defect should clean up with some steel wool and break parts cleaner.

The honing you will do, likely is with a ball hone and just to put a cross hatch pattern in the cylinder to assure proper ring seating? This is not going to take off any significant amount of material, nor will it cover the entire area evenly. There will be deeper and there will be shallower grooves. None of that will clean up pitting, unless it is very minor.

I'd clean the walls with a fine steel wool as good as you can and then give it a shot and see how they look after honing. Maybe you get lucky and it is minor enough to clean up. If it is still there after honing, get a set of replacement cylinders.

Hope this helps.
George

That I'll try tomorrow. Thanks.

The only thing I could find with rust pitting on the net with pictures is here....
http://www.antique-engine.com/abel/abel02.htm
Kind of neat and the LaBlond videos here http://www.antique-engine.com/video/videoclips.htm

The rust of course looks nothing like the above. It is speckled. sporadically speckled on the inside wall. It is not in the ring step area. I can close my eyes and move my fingers through the cylinder, and over these spots the metal is still smooth. The "pitting" I've never seen in a defective cylinder so I can't ID it. What appears as pitting I can still run my finger over and is smooth.

(The one defective cylinder I've already thrown out has what I term as a "gouge", I could not smooth it at all with 180)

I may take a pic after steel-wooling but my digital is low resolution. In the meantime I'll work on checking of the availability of a decent replacement.


Also, the grape hone to me literally is "fine haired" hatch.. Is this what a grape hone hatch should look like?

Thanks
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Last edited by H.G.P.; 01-08-2005 at 12:28 AM..
Old 01-08-2005, 12:13 AM
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Quote:
Originally posted by H.G.P.

The rust of course looks nothing like the above. It is speckled. sporadically speckled on the inside wall. It is not in the ring step area. I can close my eyes and move my fingers through the cylinder, and over these spots the metal is still smooth. The "pitting" I've never seen in a defective cylinder so I can't ID it. What appears as pitting I can still run my finger over and is smooth.
H.G.P:

Well, if you can see it, it is there. To catch it with your finger nail or feel it with yor finger tip, it would have to have a rather aprupt topography, e.g. like the edge the top ring creates in a worn cylinder. Who knows, you may be fine after honing, I don't know. And it also depends much on what lifetime you expect to get from your rebuild. A 40-50k mile goal can be achieved with things that aren't perfect. If you want 100k+ miles, I'd be more careful.

I have never honed 911 cylinders, only American iron. On a water cooled engine, I'd just go get it overbored at a machine shop, if there would be any rust on the cylinder sidewall ...

Quote:
Originally posted by H.G.P.

Also, the grape hone to me literally is "fine haired" hatch.. Is this what a grape hone hatch should look like?
Thanks
Yes.

I remember seeing very nice images of hone marks in some old haynes manuals, it may be worth flipping through them at the auto parts store. I remember even the angle being indicated at 30-40 degrees. Also, search the web for images, since any cylinder with a piston in it should look the same!

Here are some pictures of a couple of engines I was working on in the past. I still had these pics on the computer. While they aren't air cooled cylinders, they may help in trying to illustrate the size and orientation of the hone marks. These are crops out of larger images, so their resolution isn't quite up to what I'd have if I would have taken them solely to document the hone marks ...

This here is a cheap short block engine from an engine remanufacturing place. This is what the "pros" finish looks like. Including the dirt! I cleaned this one very well before it went together, trust me. Bore is just over 4" diameter.



This here is an engine that I re-ringed. It was a case of neglect (never changed engine oil and gummed up the valve guides to the point where the valve stems ran dry), so it wasn't worn beyond specs and could be brought back with a hone. Bore is just over 3.7".



This is the same engine just when I started honing. You can see the honed cylinder to the right and the unhoned one to the left. I use a ball hone but forgot the spec on the grit.


Hope this helps! If you are local to the bay area, I'd be happy to come by and take a look and I could also lend you the hone I have.

Cheers, George
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Old 01-08-2005, 01:07 AM
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I assume you've checked the bore roundness.
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Old 01-08-2005, 06:20 AM
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Quote:
Originally posted by aigel
H.G.P:

Well, if you can see it, it is there. To catch it with your finger nail or feel it with yor finger tip, it would have to have a rather aprupt topography, e.g. like the edge the top ring creates in a worn cylinder. Who knows, you may be fine after honing, .






This here is a cheap short block engine from an engine remanufacturing place. This is what the "pros" finish looks like. Including the dirt! I cleaned this one very well before it went together, trust me. Bore is just over 4" diameter.



This here is an engine that I re-ringed. It was a case of neglect (never changed engine oil and gummed up the valve guides to the point where the valve stems ran dry), so it wasn't worn beyond specs and could be brought back with a hone. Bore is just over 3.7".



This is the same engine just when I started honing. You can see the honed cylinder to the right and the unhoned one to the left. I use a ball hone but forgot the spec on the grit.


Hope this helps! If you are local to the bay area, I'd be happy to come by and take a look and I could also lend you the hone I have.

Cheers, George
The only ball hone available was the flex 180 grit, that's what I've been using, it's the only one available around here.

How many times can I flex (grape) hone at this grit (180) safely?

(Thanks George, if I didn't live several thousand miles away , I'd bring them over.)

I'll post the results of steel wool cleaning soon.

Thanks
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Old 01-08-2005, 09:39 AM
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I'm no expert, HGP, but I'd only do enough passes to get the desired finish. Do not use the ball hone to "sand" things down. It does not at all create the desired shape, it only follows the given shape and I'd be afraid you take material off very unevenly, if you'd use it for anything that gets even close to "boring".

Cheers, George
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Old 01-08-2005, 10:59 AM
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hones

Lisle makes a hone #15000 that sells for about $200 which works really well.
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Old 01-08-2005, 11:21 AM
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Quote:
Originally posted by aigel
I'm no expert, HGP, but I'd only do enough passes to get the desired finish. Do not use the ball hone to "sand" things down. It does not at all create the desired shape, it only follows the given shape and I'd be afraid you take material off very unevenly, if you'd use it for anything that gets even close to "boring".

Cheers, George
1. Used the extra fine wool, and it immediately took off all the rust spots (pin tip rust spots). After this process, there were left only pin tip dots to the sight but not to the touch. (Not many) And there are no dark areas.

2. When I use this grape hone, my understanding is it is designed to create a "plateau" finish. When I first removed the old pistons (all with good rings, with the exception of the broken valve clyinder head), I could see the old hatch in all the cylinders.

3. This old hatch, the appearance was in larger swaths. The new hatch, with the flex-grape hone, appears different in that the "hatch" is more fine, shorter in length, and not as angular. Is this correct?
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Old 01-08-2005, 08:53 PM
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I am unsure what you mean with "plateau" finish.

The new hatch will look finer. The old hatch was like that before the engine got miles on it. After it is run for some time, the finer and shorter grooves will disappear, only leaving the deeper grooves which also are longer. I have seen cylinder walls with 200+ thousand miles on V8 cars which still had significant hone marks left. But just like you describe, it was only the long and deep scratches.

The angle is nothing to loose sleep over. I'd say anything between 20 and 40 degrees will work. If you are angled further away from the plane of the cylinder ring with your hatch, you are moving the drill up and down to fast, or you need to crank up the rpm of the drill.

I sure hope someone that knows honing on the flat six will chime in before you are ready for re-assembly.

Cheers, George
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Old 01-08-2005, 10:16 PM
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Please correct me if I am wrong;
It looks like a good approach is to use some fine steel wool FIRST and then hit them with a grape hone to get the cross hatching.

Cheers
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Old 01-09-2005, 06:06 AM
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Va914:

Absolutely correct. I meant to use steel wool first and then hone. Fine steel wool isn't very abrasive, but I would still worry that it takes the bite out of a hone to the point where the rings would have trouble breaking in.

George
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Old 01-09-2005, 09:10 AM
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Quote:
Originally posted by aigel
Va914:

Absolutely correct. I meant to use steel wool first and then hone. Fine steel wool isn't very abrasive, but I would still worry that it takes the bite out of a hone to the point where the rings would have trouble breaking in.

George

I am surprised that even in the books, I have found very little, (if any) pics/comparisons in new vs. used cylinder walls, and damaged walls. (Even in the books, I have found little even in new cylinder inner walls.)


1. I finished flex honing today/early evening, they came out all very well. The only thing noticable, not really felt, is what I can only approximate, is a thousands or less minute imperfection in the 6th cylinder. It is not in the ring step area.

2. Once again, all the flex hone after results are minute hair lines.

3. Using the new piston and the newest Biral cylinder, I decided to use as a baseline with a piston test fit.

4. With the new piston/cylinder, I performed a piston test fit. Without a stock feeler ribbon, I used a splice of paper.

The results from the sides of all cylinder walls tested, was basically the same resistance as the baseline, with lubricated piston movement, including cylinder #6. Here I am happy.

5. Inner dial caliper about the same all cylinders, but innacurate as mine extends only so far. I will check on the availability of cheap inner micrometer tomorrow.

6. Lastly, after honing I feel no fingernail "lip" demarcation at the very upper cm. of the ring step area. (I do feel obe extremely small undulation (cm or less), in #3 clinder lip.

All pics dark areas are only shadows from the lighting, there are no dark areas on any cylinder




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Old 01-09-2005, 07:52 PM
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While these look clean, I can hardly make out hone marks. Is that your camera, or is the cast iron harder than your average cast iron block and hence gets machined less by the hone?

I think what you have is what you will have to work with and as long as you do not expect 100k miles out of it, rather than about 50k, you should be fine.

If I were you, with the fine hone, I'd plan on breaking the engine in under load. That means having the car ready to DRIVE to break the engine in. This way the cylinders will see more pressure, pressing the rings harder against the cylinder walls. If you can't see yourself breaking it in driving, you may consider renting dyno time and breaking it in on a dyno - under load, of course.

Bore gauges are a must, otherwise you fly blind. Did you check piston to cylinder clearance? You can get a coarse idea by inserting a feeler gauge. The better way is to measure the pistons and the respective bores. You may be able to match pistons with cylinders for better tolerances.

You can measure overall taper of a cylinder with the "ring and feelergauge" method. You use a piston ring (new or old) and shove it into the bore. I like to use a piston to level it perfectly in the bore. Then measure the piston ring gap. Measure in 4-5 areas of the bore, from top to bottom. This basically leaves you with the variation in the circumference of the bore. It is not an accurate method but if you factor in a safety factor, this method is capable of giving you a go / no go for re-ring, at least regarding the taper, not really the out of roundness.

Report back the numbers and I will be happy to help estimate if your overall taper is tolerable by looking it up in my books.

Hope this helps,

George
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Old 01-09-2005, 11:33 PM
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Quote:
Originally posted by aigel
While these look clean, I can hardly make out hone marks. Is that your camera, or is the cast iron harder than your average cast iron block and hence gets machined less by the hone?

check piston to cylinder clearance? You can get a coarse idea by inserting a feeler gauge. The better way is to measure the pistons and the respective bores. You may be able to match pistons with cylinders for better tolerances.
George

Yes! I do believe I have hatch. It looks like (B) below here:

http://www.brushresearch.com/Index.cfm/FuseAction/home.FlexHoneTools.htm

Also on the left menu under "Applications Report" they have an automotive application.

Here is a magnified view of my hatch especially first pic through magnification:





Instead of a feeler gauge so as not to disturb the metal, I am using very thin (but just barely rigid) paper splices.
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Old 01-10-2005, 11:01 AM
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(ignore the red dot camera pointer, the hatch can be seen at the bottom)


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Old 01-10-2005, 11:07 AM
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How do you check clearance with a piece of paper? What is your paper test doing? If you want to check clearance, as in room between the piston and the cylinder, you will have to insert a gauge. At least a plastic shim cut from plastic shim stock, if you are worried about scratches.

After looking at those wall profiles on the hone manufacturers webpage, I now understand what you mean with a plateau. But does that really matter? Once you start running the engine, it will be a plateau pretty quickly.

Now, back to the hone. I think it looks fine, still, but it will be sufficient. Your angle seems flatter than 30 degrees, but that should be no problem either.

I remain with my recommendation to run this in under load. It will give it the extra leverage you may need in a used cylinder with questionable shape. Which brings us to the question: "Did you measure the bore yet?"

Cheers, George
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Old 01-12-2005, 01:12 AM
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Update: I checked the ring gap(s),with the new Goertz rings, and well within the tolerances of both Haynes and Wayne's book.

My caliper close to the tolerances in the "worst" appearing cylinder for bore diameterfrom Waynes book, but I still haven't measured all way down the bore.
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Old 01-12-2005, 04:12 PM
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