My Concern:

After Lapping to bring the side seal surfaces back in spec, there is a good chance that the "nitrided layer" has been compromised.

My preliminary research has shown there to be 2 major Nitrided Processes: Salt Bath and Ion Diposition.

Is there any advantage of one over the other?

Here is a description of the Salt Bath Process:

http://www.finishing.com/kolene/qpq/index.html

Here is a brief description of the ion-nitriding process:

http://www.solaratm.com/pdf/in.pdf

The following are unknowns to me:

1. What is the surface finish (in RA) of a factory iron?
2. What is the surface hardness of the factory nitride coating?
3. What is the Case Depth?
4. Is the nitride layer a Gamm Prime?, Epsilon Prime or is it a Mixed Phase?
5. Are the Irons Cast iron or Cold Quenched Cast Iron?
6. What is the Temperature Tolerance of the Irons for dimensional stability?

 

Damn you asked a mouthful! Brandon (No7Yet) said on the resurfacing thread that it has a 900 Vickers hardness. I believe he got that from a Mazda SAE report.
I know that the nitride surface is incredibly thin and it does not take much lapping to go through it.
Good luck.

 

I may have to go back and read it, I tend to skim over trashy type posts by individuals

 

Well that was the only information he posted. He may be willing to look it up for you though. PM him.

 

how come you can't use the spray stuff on the side housings scalliwag?

 

I'm setting up to do it now but it is not even ready for testing yet. He is ready to get his done now.

 

This process is to restore lapeed housings that are still in Spec.

 

Damn. I almost missed that post.

I guess I won't sully "your" thread with any "trashy type" answers, then.



Brandon

 

If youm have somrthing useful to contribute please do

 

hmm, there pretty shiney, really smooth, really really thin, and pretty damn hard. seriously though, I think mazda went with you plain old garden variety gas nitriding

 

That was helpful! Thanks

 

I have heard of titanium nitriding like you see on drill bits and mills (it looks kind of gold in appearance) The reason I have not spent a great deal of time researching that though is because it is no more than a few mil's thick and would not help in my resurfacing endeavor.
Whether or not it would hold up to to environment inside a rotary? I never made it that far. But since you are still within spec on your plates it would be worthwhile to look into.

 

Here is a link to a equipment manufacturer that their sales people should be able to answer some of the questions as well as point you to someone to do the work.
http://www.nitriding.biz/

 

I have found a local shop that does ion nitriding I just wanted them to replicate the stock specs.

 

Hell Banzai if they have a better process give it a try. Come on dude you got more ***** than that!

 

If re-nitriding was cost-effective, why do all the major rebuilders (and the minor ones, too, for all I know) toss housings in the trash as soon as the original nitriding is beyond spec?

 

We are talking about side plates that are within spec though. Nitriding would not help if it was out of spec because it does not build the surface back enough to really help.