Does glaze exist and should we remove it?

After I asked my question about the Flex Hone grit, I started thinking about one of the responses which referred to a post which referred to an SAE paper which said not to deglaze cylinders which did not require honing for size. Since I can't get too dirty this morning because of having to visit my grandson's soccer game, I spend a couple of hours Googling the subject. It seem there are a number of articles which refer to the one article talking about the SAE paper but no specific info as to where to view the paper itself. The deglaze vs not seems to be about 100:1 in favor of deglaze, some using only a Scotchbrite pad by hand with some lubricant or solvent to keep any particles suspended.

So dear forum members, when you put your motor into bits before refurbishment, is there an actual coating on the bores or are they generally as smooth as the proverbial baby's bottom? Does the type of ring used mandate the deglaze? Are we deglazing just because our fathers did it? I have entered questions on the web sites of a few ring manufacturers ansking the question. Hastings is the only one which has a reference which states to always deglaze with new rings. If any of you actually have some evidence-based articles to quote, I'd love to read them.

A flexible hone will not fix irregularities in a cylinder wall, it will make them worse. Imagine sanding out the inside of an hour glass. So before deciding whether or not to "break the glaze", you should figure out whether or not the walls of the cylinder are still parallel (or close enough to it) to leave them alone. I was taught never to use a ball hone on an untrued cylinder. To me this means start with a rigid hone, rebore it, or leave it alone.

Russ

Yep what's been said above, plus only thing to "de-glaze" are the wear particles left by abrasive tools used in bores. Bores usually wear tapperd from one end to the other or barrel shaped. Lips tend to form at top where rings stop and reverse.

rvich said:

A flexible hone will not fix irregularities in a cylinder wall, it will make them worse. Imagine sanding out the inside of an hour glass. So before deciding whether or not to "break the glaze", you should figure out whether or not the walls of the cylinder are still parallel (or close enough to it) to leave them alone. I was taught never to use a ball hone on an untrued cylinder. To me this means start with a rigid hone, rebore it, or leave it alone.

Russ

Click to expand...

I agree.
Deglaze with 220 three blade hone for probably 10 to 15 seconds a side. If you do not deglaze, the new rings will take a much longer time to set and stand a good chance to not set at all. Again, deglaze with 220 three blade hone for probably 10 to 15 seconds a side and use plenty honing oil. I have done this under a stream of mineral spirits (parts washing tank) with great success.

On sale for $19.99
http://www.harborfreight.com/4-inch-eng ... 97164.html
Even if you only use it once, it's worth it.

Edit. If you have a visible cross hatch already, some have gone in with a non abrasive scotch brite pad and lacquer thinner.

When the surface of a cylinder becomes "glazed" oil consumption will increase and compression will decrease. The glazed surface needs to be physically removed and new rings fitted, in order to restore original levels of performance. Best possible way to deglaze a cylinder is to use a "Flex Hone" as this will remove the glaze and provide ideal surface finish for the new rings, but will not remove the amount of material to eb expected if a conventional hone was used. Some very interesting info on this here: http://www.brushresearch.com/pdf/GB.pdf

So what is "glaze"? Is it just a totally smooth wall without cross hatching or is it actually a removable deposit? Is the loss of compression just due to ring wear?

Well Doc,
It seems we are just scratching the surface (or removing some glaze) on this topic. The photo is of my 850 cylinders. They clock shows just over 6000 miles. It is difficult to get a good picture but the original cross-hatching is still visible in both cylinders. So, this is probably my bias toward not touching it as I don't really want to remove more metal. My original post was a bit hasty in the attempt to be brief. If your cylinders are truly shiny and still in spec, then probably you should run the hone through there. This actually fits with what the manufacturer says. I have to wonder based on the above as to how many miles it really takes to lose all original cross-hatching and if at that point you shouldn't be thinking about going up a size.
As to whether or not glaze exists, probably. Cast iron is very pouros. I can imagine oil being baked into those pours and the original cross-hatching. Does it require honing to remove it? That part I don't know about. I am out of brake cleaner, but that is what I plan to use on these cylinders for the final clean up. You can see there is still some carbon near the top that has not been removed. So far, these were soaked in ATF and acetone while the bike was assembled. Then into a bucket of kerosene after. This loosened most everything on them and the pistons. Is this the right approach? I can only hope so.

Russ

My bike too has only about 6k on the clock and I too hope I'll see just smooth bores and I'll just clean them with a Scotch pad and wash them down before installing new rings. Now do I put in just iron rings or chrome? Oh, decisions decisions decisions!

Hi Guys,
When its time to clean those cylinders from whatever you used (hone, sandpaper, or scottbrite) the easiset way is just take them over to the shop sink and use dish detergent and hot soapy water, and maybe some sort of brush. This will quickly and completely remove all of that gray honing residue. Once you are done rinsing immediately spray the wet cylinder with WD-40 (or some sort of multi-purpose lube) then blow the rest of the water off. If you try to dry it without first oiling it will rust really fast.

GB

The cylinder pictured doesnt look like its glazed to me.............deglazing and honing are 2 distinctly different processes though, and on an engine where the cylinder geometry is correct, and which is merely having new rings fitted, there is no need whatsoever to have the cylinder honed, and deglazing with a brush type tool is all that is required.

rvich said:

Well Doc,
It seems we are just scratching the surface (or removing some glaze) on this topic. The photo is of my 850 cylinders. They clock shows just over 6000 miles. It is difficult to get a good picture but the original cross-hatching is still visible in both cylinders. So, this is probably my bias toward not touching it as I don't really want to remove more metal. My original post was a bit hasty in the attempt to be brief. If your cylinders are truly shiny and still in spec, then probably you should run the hone through there. This actually fits with what the manufacturer says. I have to wonder based on the above as to how many miles it really takes to lose all original cross-hatching and if at that point you shouldn't be thinking about going up a size.
As to whether or not glaze exists, probably. Cast iron is very pouros. I can imagine oil being baked into those pours and the original cross-hatching. Does it require honing to remove it? That part I don't know about. I am out of brake cleaner, but that is what I plan to use on these cylinders for the final clean up. You can see there is still some carbon near the top that has not been removed. So far, these were soaked in ATF and acetone while the bike was assembled. Then into a bucket of kerosene after. This loosened most everything on them and the pistons. Is this the right approach? I can only hope so.

Russ

Click to expand...

Deglaze is to produce a "break in" surface fo New rings, clean the finnished bore with kitchen towl and oil..alar Cummins.

I got a response to a question I had asked of the Mahle piston folks who now own Perfect Circle piston rings and they advocate deglaze and wash before new rings; they didn't specify how the bore looks before the deglaze as to if the cross hatch marks are still there would it be necessary.

I'm going to get a set of bore gauges and a larger micrometer and actually measure the bores before I do anything. I would hope on a low-mileage machine I'll still be in spec. Then I actually have to make a decision.

Get a good look at your bores. You can use the old trick of putting one of your rings at the bottom of the bore where there is no wearing and measure the end gap. Then move it up and measure the end gaps at different heights. It is crude but it gives you pretty quick idea of how much wear there really is.

My line of reasoning is that if the perfect surface is plateaued with grooves to spread the oil, I have that now.

I will be curious as to what you choose for rings. I would still like to know if cast iron rings cause less wear on the cylinder walls. If so it might be a good excuse to use them and just replace them more often. However, if you honed at each change it might be moot.

Russ

The best way of assessing cylinder wear or problems caused by less than perfect machining is by using a proper bore gauge: http://www.bowers.co.uk/products/show/9860