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Prepping Irons (Sanding??)

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Old Jul 14, 2020 | 02:29 PM
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Prepping Irons (Sanding??)

I'm in the process of rebuilding my s4 n/a 13b and I keep finding contradicting info on how I should be prepping my irons. Supposed god of rotary: Lynn, E Hanover has a method for a home lapping procedure that a lot of people seem to preach. It can be found at:
https://www.nopistons.com/rotary-eng...rebuild-73338/

The issue with this is the lack of general consensus of "lapping" at home.

All these threads below are essentially calling OP an idiot for sanding his irons
https://www.rx8club.com/series-i-tec...t-help-233852/
https://www.rx7club.com/1st-generati...-like-1135998/
https://www.rx7club.com/2nd-generati...s-home-910197/

Meanwhile a majority of the people in these thread would jump off a bridge if Lynn said it was part of the procedure
https://www.rx7club.com/3rd-generati...-irons-917523/
https://www.rx7club.com/3rd-generati...ppers-1076811/

No, I don't want to get told to buy new irons, send them in to get lapped/re-nitrided, etc. because half the people in the threads posted above have already said that. I just want to see if anyone has something to say about this discrepancy with hand-lapping the irons since most of these debates were over 10 years ago.

Ideally other people in my situation can find this thread and decide "ahh so I ____ follow Lynn's procedure"

Thanks
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Old Jul 14, 2020 | 07:15 PM
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Sounds like you made up your mind. Just do it and you will find out if it works or not. It is your car. Like 10 years ago , many on here are going to tell you get use ones withing specs or new ones.
good luck..
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Old Jul 15, 2020 | 09:40 AM
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From: https://www2.mazda.com/en/100th/
The irons are a regular cast iron with a Nitride coating. the Nitride coating is hard, and helps with lowering friction. The iron by itself is soft. The older Pre-Rx7 cars had a harder iron and no coasting, lapping these was encouraged. a Nitrided iron without the coating will wear very fast.

you want the irons as flat as possible, but you also want to keep the Nitride coating as much as possible. you can have the iron re-nitrided, but it costs more than a new iron

i would suggest that the least amount of Mr Hannovers method is good, you keep as much coating as you can, plus iron is flatter.
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Old Jul 15, 2020 | 09:52 AM
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Hmm I'm hesitant to take a powered disc of 180 grit to my irons just because I feel like that would remove a lot of material rather quickly. Would it be worth it to give them all a light wetsand with 1000 grit or something like that? That's what some guy at a car meet told me. Or will that not do anything and at that point just be better to leave them as is?

I attached some pics of how they currently look in case that changes things



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Old Jul 15, 2020 | 12:47 PM
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From: https://www2.mazda.com/en/100th/
did you measure them? do they need any work or are they in spec?
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Old Jul 15, 2020 | 12:55 PM
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They seemed to be in spec after following a couple guides to check certain wear spots
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Old Jul 15, 2020 | 08:49 PM
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If they are within spec you should be good then. No need to mess with lapping them.
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Old Jul 15, 2020 | 10:33 PM
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Yeah I guess that makes sense. So nothing should be done to them? I thought one of the main reasons this method was posted was to improve oil retention during a rebuild.
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Old Jul 16, 2020 | 06:58 AM
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No.. you dont have to do anything.
Lapping is done to bring out of spec irons within specs and be able to use them.
you just need to clean them really good and put your engine together.
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Old Jul 16, 2020 | 09:00 AM
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From: https://www2.mazda.com/en/100th/
Originally Posted by DirtyVert
Yeah I guess that makes sense. So nothing should be done to them? I thought one of the main reasons this method was posted was to improve oil retention during a rebuild.
if its good its better not to mess with it.
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Old Jul 16, 2020 | 10:22 AM
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Hell yeah appreciate the help guys!! Hopefully will get some work done this weekend
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Old Jul 19, 2020 | 06:14 PM
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STOP! I have to agree with everyone else. Do not sand your irons at home please. Find the procedure and determine if they're within spec or not.
Im new here but not new to the rotary engine. And I will respectfully disagree with those methods.
If they're within spec, give them a nice cleaning, inspect them and use them. Best of luck.
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