Ok, so back when renesis was first announced I looked at all the insider information I could get my hands on, spy photos and what not. I noticed this problem way back but I since forgot about it, now that the RX-8 is out and these renesis engines are available to the masses maybe someone can check this out on their RX-8 or crate renesis motor for me/us.



One of these 'spy photos' showed a torn down renesis motor from a RX-8, the photograph was of the rear iron housing showing the wear surface and side ports:





Do you notice anything wrong in this picture?



I do, first theres a shitload of surface rust in the water jacket area on what is supposed to be a new engine, which I don't quite understand. But it gets worse, look at the nipple on the upper left of the iron, the one that on past rx-7's was used to provide coolant for the BACV. It looks rusted already, no? Not only does it look rusted, it doesnt look like it's plated like the coolant nipples usually are? WTF?



Look at the heater hose nipple on the right side in the above picture, it has that plated color to it, and note, no corrosion is apparent. Compare the color to the BACV nipple with the corrosion, entirely different finish.



Now, I have purchased new housings from mazda in the past, and here is a picture of a S5 NA rear iron brand new straight out of the box from mazda (note it has been ported though):





and another view, harder to see the color of the nipple though:





There is clearly a problem here, now, would any of you rx-8 owners be willing to lose some coolant and get a picture of that nipple on your production rx-8 for us? You might have another reason to call mazda headquarters because if that nipple isnt plated you can bet the bank it won't last, it looks to be already corroding in the above picture not even a year old, I'm guessing still a newborn.



If it is confirmed that this problem exists on the current RX-8's, it makes me seriously wonder what other quality control problems there are with this car, the ones we didnt manage to catch in photos posted on the web.

 

this makes me very sad and pissed, i hope to see more proof of this.

 

could the corrosion in the coolant passages have happened after the motor was apart?

 

yes. it also might have been sitting around before they pulled it apart

 

Good point, but it was at least freshly torn apart. Even if it had sat around it doesnt explain the nipple.



I'm surprised there are not more responses to this thread.

 

It looks like the engine ran at least for a short period of time before they tore it apart... so i had coolant in it, probably just tore it apart and it's rusted a bit from sitting, or maybe they live in a costal region where the picture was taken and the salt water in the air... i don't know... I suppose that's just a stupid thought



As for the nipple they must have started plating those on the S5's because my S4 isn't plated, quality control might be an issue, anyone know where the Rx-8 engines are getting assembled?

 

The rust is prolly not a big deal, I've honed cylinders on motors only to walk out an hour later... yes one hour to find little corrosion spots growing and I've had some pits from letting them sit overnight (always use "honey" on freshly hones cylinders)

 

I have S4 housings at home I'll photograph later tonight after work.



I'm pretty sure they are plated, the nipple in the rear housing is the same nipple from the water pump housing (pressed in). This picture is of a S4 water pump housing with the nipple pulled out... you can see the plating but it's still corroded (1987 engine), imagine how bad it would be with no plating.







I'll put photos of S4 housing nipples up later, maybe someone else has pics laying around of this stuff?

 

Plated? You are referring to galvanization, no?



I own a few S4 motors myself, and I've worked on other S4 motors. I have yet to see a single coolant (to TB/BACV, what have you) that is not galvanized.



The galvanization can wear off, so I wouldn't say that they weren't galvanized from factory. Look at Pengs picture. Where he is clamping, parts of the galvanization have worn off - Where the furrel was inside the cast housing, it still looks fresh from not being exposed to the elements.



As for Mazda not galvanizing them from factory I find that hard to believe. But there it is in the picture there.



That's especially funny looking when that nipple is sitting next to a gavlanized bracket, and further to the right, a galvanized bolt in the iron, and another galvanized hose fitting (which looks to be for the heater core?).

 

correct me if I'm wrong, but galvanizing and plating are one in the same, no?



and yes, i agree with you, it is hard to believe and plain as day right there in the photograph. I really would like to see someone with a rx-8 pull that hose off and snap a picture, maybe it was just an early (pre?)production issue.