I do have to add one thing a couple of threads up there was a comment about leaving the cylinder in the oven for a couple of hours. what you are doing is heat treating the liner, if you leave it in that long, now the material is hard as a brick bat, I have had my cylinder guy bitch a few times when I left the cylinder in too long or had to heat it up too much , he can tell by the chatter on the boring bar if the hardness has been increased or not.
As far as the comment above do yourself a favor do it once and do it right the first time, different sized cylinders is not doing the job right and the replacement sleeve is going to have to be bored anyway, they are undersized and have to be bored to stock cylinder size , bore both holes the same size an put in two new pistons..
Heat Treatment Steel: Hardening
The intent of hardening is not just to harden the steel, but also to make it stronger. Unfortunately, there aren’t just plusses to hardening. While hardening does increase strength, it also decreases ductility, making the metal more brittle. After hardening, you may need to temper the metal to remove some of the brittleness.
To harden most steels, you would use the first two stages of heat treatment (slow temperature heat followed by soaking by a specified time to a uniform temperature), the third stage is different. When you harden metals, you rapidly cool them by plunging them into water, oil, or brine. Most steels require rapid cooling, called quenching, to be hardened, but there are a few that can be successfully air-cooled.
As alloys are added to steel, the cooling rate that’s required to harden it decreases. There is a silver lining to this: the slower cooling rate lessens the risk of either cracking or warping. The hardness of carbon steel depends on its carbon content: up to .80% carbon, the ability to harden increases alongside the carbon content. Beyond .80%, you can increase wear resistance due to hard cementite forming, but you can’t increase hardness.
When you add alloys to steel to increase its hardness, you also increase the carbon’s ability to harden and strengthen. That means that the carbon content needed to produce the highest level of hardness is lower in alloyed steels versus plain carbon steels. As a result, alloy steels typically offer better performance than plain carbon steels. .
When carbon steel is hardened, the steel must be cooled to under 1000°F in less than one second. But, once you add alloys to the steel and increase the effectiveness of the carbon, you increase that time limit beyond one second. That allows you to select a slower quenching medium to get the specified hardness.
Typically, carbon steels are quenched in brine or water, whereas alloy steels are quenched in oil. Unfortunately, quenching is a process that produces high internal stress and, to relieve the steel, one option is to temper it. Right before the part becomes cold, you remove it from the quenching bath at a temperature of 200°F and let it air cool. The range of temperature from room temperature to 200°F is called the “cracking range,” and you don’t want the steel in the quenching medium to pass through it. Read on to learn more about tempering.
