1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

DIY Iron Resurfacing – what should they look like?

Thread Tools
 
Search this Thread
 
Old 05-17-19, 02:23 PM
  #1  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
DIY Iron Resurfacing – what should they look like?

I'm cleaning parts to assemble an engine and I followed the Lynn Hannover method of DIY resurfacing the irons without messing up the nitride coating (dry 180 grit, then 5 minutes of wet 400 grit with kerosene on a DA). My irons had some surface rust and stains. I got the surface clean but it doesn't look like I expected. In the light I can see a pattern on the surface, almost like a bunch of small pock marks. Is that how it's supposed to look or did I mess something up? Or maybe I need to spend more time sanding?

Also I know there is step wear, but it's under 0.003" (spec is 0.004")




Old 05-20-19, 10:48 AM
  #2  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
Anybody? I don’t want to do a rebuild with bad irons and I can’t find pictures of resurfaced irons online
Old 05-20-19, 12:30 PM
  #3  
Lapping = Fapping

iTrader: (13)
 
Jeff20B's Avatar
 
Join Date: Aug 2001
Location: Near Seattle
Posts: 15,725
Received 70 Likes on 64 Posts
I would not do what you are doing. .003" is within spec so I'd just use them as is with no funny business attempting to sand them down or whatever. These nitrided surfaces are not piston bores and should not be treated with the same mindset. While it is true piston rings and side seals are made of similar materials, that is where the similarities end.

I would stop what you are doing and assemble the engine now. I say this because all you are doing is wearing away the hard surface and shortening the life of your irons and any seals that ride on them. Ever torn down a resurfaced engine before? It's pretty bad. Usually nothing is reusable that had any sort of contact with the irons.
Old 05-21-19, 12:17 PM
  #4  
Rotary Enthusiast

iTrader: (8)
 
dguy's Avatar
 
Join Date: Apr 2006
Location: sb
Posts: 1,471
Received 210 Likes on 158 Posts
If it's not for a client just slap it together.
Old 05-21-19, 12:19 PM
  #5  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
Im not sure about that. I read most threads on this forum about it before I started. I definitely did not attempt to reduce the step wear and it looks like I didn’t. It’s still the same as when I started. What I did do is remove the staining and surface rust that was on these irons.

This thread convinced me to do it: https://www.rx7club.com/3rd-generati...ppers-1076811/

From what I’ve gathered, you can do this a lot before you get through the coating
Old 05-21-19, 02:41 PM
  #6  
Senior Newbie Member
 
Frogman's Avatar
 
Join Date: Jun 2017
Location: Downey California
Posts: 1,048
Received 89 Likes on 77 Posts
Originally Posted by derSchwamm
Im not sure about that. I read most threads on this forum about it before I started. I definitely did not attempt to reduce the step wear and it looks like I didn’t. It’s still the same as when I started. What I did do is remove the staining and surface rust that was on these irons.

This thread convinced me to do it: https://www.rx7club.com/3rd-generati...ppers-1076811/

From what I’ve gathered, you can do this a lot before you get through the coating
if you do do this you are locking yourself into OEM seal territory. Plenty of youtube videos showing people getting low compression using aftermarket seals after doing a resurfacing.. as stated above your better off just using them as is. I can guarantee you won't get noticeable compression gains .
Old 05-21-19, 02:53 PM
  #7  
Waffles - hmmm good

iTrader: (1)
 
t_g_farrell's Avatar
 
Join Date: Jul 2004
Location: Lake Wylie, N.C.
Posts: 8,783
Received 282 Likes on 232 Posts
Whats the difference in the thickness of the nitriding on an 13B plate versus older 12A plates? Maybe it works for 13Bs.
Old 05-21-19, 03:38 PM
  #8  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
This is an S5 13b I’m building to drop into my FB. I did order an Atkins rebuild kit already with OEM corner seals and plugs.

I’m surprised to see such a different reaction to doing this in the first gen section than the third gen. I was expecting some feedback on how the irons should look but it seems like everyone thinks I ruined the nitride layer? Not sure how I took that much off when the step wear didn’t change
Old 05-21-19, 07:29 PM
  #9  
Senior Newbie Member
 
Frogman's Avatar
 
Join Date: Jun 2017
Location: Downey California
Posts: 1,048
Received 89 Likes on 77 Posts
To be fair the third gen guys blow motors up like its no body's business .
Old 05-22-19, 10:25 AM
  #10  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
Originally Posted by Frogman
To be fair the third gen guys blow motors up like its no body's business .
I can’t argue with that!
Old 05-28-19, 05:36 PM
  #11  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
Alright, I cleaned up the front iron with only wd40 and a few scotchbright pads. After a while I got to this point. It doesn't look perfect but is it good enough? Interestingly I got the same textured look I saw in my center iron above, so now I'm wondering about that one again too. Thoughts?

Old 05-28-19, 05:41 PM
  #12  
Lapping = Fapping

iTrader: (13)
 
Jeff20B's Avatar
 
Join Date: Aug 2001
Location: Near Seattle
Posts: 15,725
Received 70 Likes on 64 Posts
It looks decent. Scotchbright is what I've used with fine results.
Old 06-01-19, 11:10 AM
  #13  
Old [Sch|F]ool

 
peejay's Avatar
 
Join Date: May 2001
Location: Cleveland, Ohio, USA
Posts: 12,506
Received 416 Likes on 296 Posts
Ugh... that side seal groove is going to eat oil control rings. I have a pile of 12A side housings I won't use because of wear like that and they don't look nearly that bad.

It also looks like it's worn through the hardening anyway. You can see a definite change in "surface texture" in that vertical trough.

All is not lost, Chips Motorsport will grind, lap, and re-nitride housings for something like $700 a set, which includes new core plugs everywhere. Basically they are completely remanufactured. Great deal for what you get. Is why I have a pile of 12A side housings, and haven't scrapped them.

Last edited by peejay; 06-01-19 at 11:13 AM.
Old 06-02-19, 11:20 AM
  #14  
1st-Class Engine Janitor

iTrader: (15)
 
DivinDriver's Avatar
 
Join Date: Jun 2008
Location: Chino Hills, CA
Posts: 8,376
Received 26 Likes on 24 Posts
The key performance factor is not the 'finish' as much as it is the flatness of the surface.

Hand-refinishing to eliminate step wear will not completely restore flatness. It just makes the variations more gradual & harder to measure.

The only way to get a properly flat iron is to have them lapped professionally, IMHO.
Old 06-02-19, 11:50 AM
  #15  
Senior Member

iTrader: (4)
 
tommyeflight89's Avatar
 
Join Date: Nov 2010
Location: Toronto Canada
Posts: 696
Received 85 Likes on 60 Posts
Originally Posted by peejay
Ugh... that side seal groove is going to eat oil control rings. I have a pile of 12A side housings I won't use because of wear like that and they don't look nearly that bad.

It also looks like it's worn through the hardening anyway. You can see a definite change in "surface texture" in that vertical trough.

All is not lost, Chips Motorsport will grind, lap, and re-nitride housings for something like $700 a set, which includes new core plugs everywhere. Basically they are completely remanufactured. Great deal for what you get. Is why I have a pile of 12A side housings, and haven't scrapped them.
Agreed. Chips rebuilt my Streetport 12A and the lap+re-nitride service is a must. His work is perfection.
Old 06-02-19, 12:18 PM
  #16  
Senior Member

Thread Starter
iTrader: (1)
 
derSchwamm's Avatar
 
Join Date: Dec 2014
Location: Austin TX
Posts: 630
Received 62 Likes on 43 Posts
I picked up another set of s5 irons in much better shape for $300, so for now these irons will sit on a shelf in case I need to get them lapped and renitrided in the future. Too many people think the coating is messed up for me to feel good about them, plus the step wear is close to the limit anyway. I’m going to stick with scotchbrite pads from now on.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cr-rex
3rd Generation Specific (1993-2002)
18
08-14-17 09:29 AM
drezjdmrx7
Canadian Forum
14
03-06-13 11:01 AM
alex91n/a
2nd Generation Specific (1986-1992)
6
06-22-10 07:15 PM
fredox19
NE RX-7 Forum
1
05-21-09 09:08 AM
fcdrifter13
2nd Generation Specific (1986-1992)
1
10-11-06 04:37 PM



Quick Reply: DIY Iron Resurfacing – what should they look like?



All times are GMT -5. The time now is 01:16 PM.