benedunn

chuffin hell phil!!! fancy you found this thread haha

IMO now im thinking the cast iron that the rx8 irons are made out of is simply cheap crap! i toold an iron down to the nitriding shop near me and they stuck it in the oven for 2 days for nowt to see what would happen ... they managed a nitride layer 14 thou deep but the faces didnt come out perfectly flat so a couple of thou would need grinding back off that!

what was intresting (and i was gonna talk to you about this if youd ring me :-P) was that they were very suprised how un hard the finish was ... i didstinctly remeber numbers like 400 and 500 being used but will have to ring them tomorrow or tuesday to have another chat about it ... long story short they said there wasnt enough of what they needed in the iron to get a truerly untouchable finish and even the nitride layer was pretty soft!!!


im now looking into other avenues we have a plasma spraying company that i already use to refurb stuff basically they spray industrial hard steel onto whatever suface you like and then grind it off to better than factory finish ... going on that 10a and early 12a were not nitide treated and relyed on the hardness of the metal itself i figure spraying on a completely new layer of supper tuff metal smothed off to within 13 RA could be viable alternative!! although it would require grinding 7 or so thou on spraying 10 thou back on and then grinding 3 thou back off so a couple of trips to the grinders


both avenues are quite expensive ... nitriding would probably be the favorite in that respect but im unsure if i trust the irons after what ive seen now!!! thats 4 engines that have all done the same thing and the only thing in common is the grinding or lapping of the irons!!!

back o what i was saying i think the tissue paper the MSP irons are made of rely completely on the nitride layer which is so thin you could see through it, just shows that they rushed manufacturing and forced costs down by skimping on material .... not surprising considering the price of the car tho

PhillipM

Well, you can make the nitriding harder on soft castings, but it means a thinner layer than usual - I reckon that's what Mazda have done perhaps. However, I think it was the debris from the warped rotor tips that did ours to start with - lesson there perhaps - don't touch the side housings, even if they're marked.

Wish I'd found out 'fore we lost the CNC mill, could have made some.