A search didn't yield any apparent results, apologies if I missed a similar thread.

I have an S4. NA keg I bought as a fun project to eventually keep as a spare if needed. That being said, I have accepted the risk of rebuilding it myself and expect there to be problems, this is mainly for learning purposes unless everything goes very well.

After opening it, I was surprised that everything looks reasonably healthy. Minor chipping, even by manufacturer maintenance booklet, in one housing post exhaust port but it appeared recently rebuilt, and mild surface corrosion from sitting on the cast iron.

My concern with getting new seals all around and closing it back up is that one rotor has a chip on the side. Doesn't appear it would interfere with sealing on the sides or corners, but I've read if it's chipped or dented it's basically a dead rotor. Obviously that is the ideal scenario but S4/5 rotors are getting expensive, is there a scenario where a chip can be 'ignored'?

I can attach photos later if necessary, but along one side is a 4-5mm long chip about 1mm deep. It mainly affects the combustion side with a small amount out of the seal side, still 1-2mm from the side seal groove.

 

A photo would help to see if rota is serviceable

 

for purchasing new engine rotors you need to import them direct from Japan

just looked at a pair and they were $200 less each including DHL shipping, exchange rate fees, etc. from Japan than the wholesale price from my Mazda Motorsports racing account! For qty. 2 I get free shipping from Mazda Motorsports, but then have to pay tax. The prices being charged here in the USA make no sense. Can pretty much order any major engine parts that are within standard weight limits for less cost from Japan.
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That's good to know, thank you for the info!

 

It is a little difficult to see in some photos, however here is what I have taken.



Last photo is probably the best for seeing extent of the chip

 

that is quite odd, but if the seal groove is ok it should be ok to run. you want to drop a new side seal in there and make sure it doesn't bind, and then check the side clearance, and if it passes that then move on to the other grooves.
you need to make sure that the rotor isn't bent, essentially

 

Side clearance to the housing at the peak or side seal clearance? And I'm assuming if it's seal clearance it would be against the rotor not the corner seal.

I still need to fully clean all of this just did a first pass and noticed the chip.

 

That rota is fine to use just remove any sharp edges off with 230 wet and dry paper

 

i was thinking side seal to the groove, but it kind of looks like someone might have dropped that, so you might check both.
Mazda has a spec for both

 

That's good to know, I haven't had a chance to fully go through the maintenance manual. I'll check it out before rebuilding for sure, thank you!