Deglazing Cylinders

[earossi]

As you may know, I am in the process of having one of my Nikasil cylinders reworked to repair a scored area found during a recent teardown of the motor for an upper end "refresh". Since all but one of the cylinders appear to be reusable I had done some research on what to do to prep the walls of the cylinders for new rings.

The common wisdom on this board, when working with Nikasil cylinders, is to merely remove the glaze from the cylinder walls since the original hone marks are clearly evident. The suggested technique seems to be using hot water and Dawn dishwashing soap as a lubricant and degreaser along with Scotchbrite pads to remove the glaze. That appears to work well in the opinion of most on this board. However, in discussing the deglazing with the firm that will be reworking the damaged cylinder, they are of the opinion that the Scotchbrite does not remove all of the hydrocarbon varnish that has accummulated in the etched areas produced by honing. They believe that the Scotchbrite simply takes off the "high spots" leaving glazing material in the bottom of the honed etch marks.

Instead, they recommend the use of Muriatic acid as an acid wash to dissolve all of the hydrocarbon that fills the honed areas. So, I thought that I would recant their instructions with the hope of getting some comments back from those of you who have done deglazing a few times.

The instructions were to purchase hydrochloric acid at the hardware store and dilute it with water going 3 parts water to 1 part acid. This weak "Muriatic Acid" is then to be wiped over the glazed walls of each cylinder using just a shop rag (and protective equipment to protect yourself from the acid). Once the acid has been applied, you are to allow it to remain on the walls for 5 to 10 minutes which should be sufficient time to dissolve all of the hydrocarbon glaze that resides on the walls and in the trenches of the honed areas. At that point, simply wipe the remaining acid and dissolved hydrocarbon off the cylinder walls using another shop rag.

Finally, throughly wash the cylinders using hot water and the Dawn dishwashing soap so that 100% of the acid wash is removed.

I was told that I could use the Scotchbrite to apply the acid wash, but that they did not consider it necessary.

Comments on this process?