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-   -   How to resurface irons at home (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-resurface-irons-home-910197/)

alex91n/a 06-24-10 03:22 PM

How to resurface irons at home
 
Can someone please go into detAil about the process of sanding down ur irons by hand. I know you want to use a large piece of San paper that's on the bottom of a large piece of plywood so that way u get even wear. If someone could give detail such as what grit sandpaper, and if there is a certain pattern i'm supposed to sand in, I.e. Little circles, big circles, left to right top to bottom etc
thx Alex

gear_grinder 06-24-10 04:28 PM

no, just no.....

Gryffinwings 06-24-10 04:52 PM


Originally Posted by gear_grinder (Post 10075701)
no, just no.....

+1

You just don't do it. You have to get them sent to a machine shop that has the proper tool and knowledge to do that kind of thing, mainly they have to be within a specific tolerance.

arghx 06-24-10 04:56 PM

and you can't exactly apply nitriding to the irons in your garage

eriksseven 06-24-10 05:05 PM


Originally Posted by arghx (Post 10075784)
and you can't exactly apply nitriding to the irons in your garage

^ exactly.

Atkins stopped recommending the service years ago because the engine's built with resurfaced irons had no longevity.

hub_01_69 06-24-10 05:07 PM

A process is shown in the Mazdatrix rebuild video using a lapping compound.

alex91n/a 06-24-10 05:15 PM

Ok well I read something on here saying that's how they used to do it back in the day.. What's the average cost to have that done? Or should I just source a new one?

SpeedOfLife 06-24-10 07:15 PM

Just buy some good used ones. New ones are $$$ and lapping + nitriding CAN'T be cheap.

MaczPayne 06-24-10 07:36 PM

From http://www.rxforyour7.com/Rotary%20Engine.htm :

"In 1979 nitride coated steel housings were introduced. This decreased the wear on the side housings from the Side seals, Corner seals, Apex seals and Oil Control Rings. The steel housings before this could be past replacement criteria at only 40,000 miles. Nitriding increased usable life up to 200,000 miles. At this point housings can be lapped or machined but they will only be good for only another 30,000 to 50,000* miles because machining will remove the nitride coating.

A point needs to be made about lapping and Blanchard grinding as it relates to long-term reliability. The nitride coating is very thin and once you have gone past the nitride you are back to pre-1979 housing surfaces. Lapping isn't as aggressive as the Blanchard process. Also, if too much material is taken off the four side surfaces of the housings, a different adjusting spacer needs to be fabricated to be able to set the end play."

Might have been acceptable to do prior to 1979, but with good housings floating around, why not pay a little extra for 150,000 more miles?

jjwalker 06-24-10 09:36 PM

Side housings are extremely cheap. I got very low mileage housings from RP for $150 a piece. New, they aren't that much either considering the long term benefit of new versus used.

alex91n/a 06-25-10 12:55 AM

Yeah I was trying to buy some good used ones. The one I bought from a member was supposed to be good. He said it was good for a rebuild but it had step wear so I guess I'll js pick up a new one.. I figured it wouldn't be that hard to resurface but obviously I was very misinformed and wrong.


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