I have had no luck finding an answer to my question through searching so any help will be much appreciated. I am in the process of rebuilding the b18a1 short block found in my 90 GS, to stock specs for a reliable daily driver, and have a question regarding the crankcase breather chamber; found on the rear of the block near the oil filter. The breather box, as I removed it, had an insulated cover a few millimeters thick. This insulation has disintegrated and is now currently in four pieces, though the breather box itself shows no sign of physical damage other than oil eaten paint.
Is this insulation required? Is it necessary to prevent overheating of the breather box, which could lead to increased pressure or some other damaging consequences? If the insulation should be used, what is the ideal replacement? Would powdercoating be effective protection? Are there any good aftermarket replacements for the breather box assembly? (oem is discontinued…) Lastly, can the chamber be safely cleaned out with brake cleaner? All hoses, joints, grommets, and o-rings will be replaced with oem parts. Thanks in adance.