My "D" series 20B is now BUILT!!!

[Herblenny]

Originally Posted by Judge Ito

nice build... did you bake on a thermal barrier coating on the side housings after they got lapped? once they get lapped, they loose the gas nitride coating that mazda puts on them.. pettit racing usually adds the thermal coating for me.. i really stay away from lapping side housings.. i try to find excellent ones for a build.. if i have no chocie then i lapped them, and get them coated..

Well, the whole nitride coating thing was an issue for me when I first found out about lapping.. But I've seen feedback with people who haven't re-nitriled after lapping and they haven't seen any ill affect.

This same question was asked not so long ago at Rick Engman's shop. The answer was that Rick laps even new irons as they are not perfectly flat... And they also don't nitrile after lapping and seen no ill results. Apprently nitrile coating also leaves unevenness to the housing so re coating after lapping seem counter productive...

In my opinion, nitrile coating seem more post production storage than actual function. As I was told the coating does come off the engine after so many miles... But it does help with rusting of the iron housing.. But who knows..