Hand lapping irons.
 

Im in the process of rebuilding my first S4 na 13B and i was wondering if anyone had any success lapping their irons. I know mazdatrix offers that machine lapping but im trying to save some cash, what did you guys use? any and all feedback would be greatly appreciated.

http://www.youtube.com/watch?v=fXfk0DrxAYY
Use valve/lapping compound.
After that you will need to re-nitrate or something better.

^Interesting! Can that introduce swirl marks into the iron though? I think the mazdatrix video shows them doing this by hand but they use a more random pattern.

This is the real way to do it...and why you see swirls.
http://www.youtube.com/watch?v=NB-nA...eature=related

Another way.
http://www.youtube.com/watch?v=0pMG7...eature=related

You just need to start out with non warped irons.

After it's lapped you can/should hand run a coarse grinding stone over the surface before you re-nitrate...It's better for break in and it will retain oil better.

I hope this helps.

Have you taken the engine apart yet? You should measure your housings and see how much wear is on them. You might be able to get away with not doing anything with them. Check the FSM to see how to do measure the wear.

I have resurfaced my housings, and personally I would pay someone to do it. I used a surface grinder to make passes back and forth on the face of the iron, then used lapping compound and rubbed the faces together like in the video above.
If you don't have access to the equipment, then it's a pain. You might be able to find a machine shop to blanchard grind your housings, but they might charge you a lot for the jig to place the parts properly.

My process looked like the last video in the last post.

Bottom line, check around and see what machine shops are willing to do it and check prices. If you don't have access to the right machines, it's worth it to pay up and get them done.

what do you mean about re nitrate, how do you do that and what will you need?