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My son has a 2006 3 with 290k on it, and just bought a 2018 3. I think you will find the 6 has an excellent powertrain.
Many fault Mazda for their engineering of the Renesis, but they certainly can build a great piston engine, better than most others. It leads me to believe they know a bit more than they get credit for.
I hope their great engineering prowess of engines will carry on with their upcoming electric plug-in hybrid drivetrains. It doesn't look like rotary will come to them though. It would be a good candidate due to compact nature.
Last edited by danwat1234; 01-28-2020 at 02:17 AM.
Yeah, regarding the oil. The thread I was watching was closed. Good thing. Here's my take, for what it's worth. I'm not a materials scientist or anything close, but it seems to me the issue is whether or not the oil burns, so it doesn't clog the cat. I have been using Castrol from day one, 5W20 as recommended. After following the "oil poet", there were many folks who swear by thicker oil. I think 200K is a testament to their suggestions. OK, for what little I know about the science it would seem that the critical factor here is the flash point of the oil. I'm not going to quote numbers here, but I did go to the Castrol site and the flash point of their original conventional oil is only 50F lower than the full synthetic, which I believe is around 650F or maybe even less. Well, the rotary is known for ow combustion temps due to the long combustion chamber, but seriously?? Combustion temperature far exceeds the flash point, so it seems to me any synthetic oil is fine. I also checked my manual after reading some of the posts on this forum and I could find no place in the RX8 manual where they warn against synthetic oil. I owned an 1976 RX-3 back in the day and it was definitely taboo then, so I never really scoured the RX8 manual for new info. I will be switching to synthetic for sure, and probably a higher viscosity as well. I only have 22K on my rig, so I can likely make it last for a very long time if I switch. Thanks, elf!!
I, too, owned an RX-3, one of the very first, a 1972.
I bought a few cans (yes, cans in those days) of the new 'Mobil1' synthetic oil, that I had seen in Popular Mechanics ( a 'magazine') (they were like the internet, but on paper.)
The very first synthetics were based on jet engine lubes, an amine technology, not the current polyolefin stuff - my poor little 12A lasted less than one thousand miles.
It developed a sudden insatiable thirst for anti-freeze) not good in a Canadian winter. Clouds of white smoke followed it.
I believe (obviously can't prove) that the Mobil ate the side seal O-rings.
Mazda was very good about it, replaced the engine, no charge. (Second owner, 70k miles!)
and requested the dealer to send it back to Japan.
Couple of years later, all the "don't use ANY synthetics!" stuff started to appear.
I've always thought the rotary would be a great choice for a plugin hybrid. Excellent power to weight ratio, so lightweight to be hauling around when you don't need it. Also, the rotary is most efficient when running at a constant speed and load, which is what you would have if they keep the drive train all electric and use the gas engine to simply replenish the battery pack. Seems like a natural to me.
Interesting. I wonder if Mazda changed the composition of the seals to avert that issue, or if the synthetic formulations these days don't cause that problem. I certainly don't want to risk that with my 8. Only 22k miles and showroom condition. Still, 200k is a pretty good endorsement. Maybe I'll switch to the purple stuff.
I too had my engine rebuilt for free with around 50k on it. It would run on only one rotor for a few minutes after startup, due to seal wear. I had heard about the seal issues before I bought the car, but it was just after they announced the extension of the factory warranty so I figured why not? I also bought mine second hand, so I was not the original owner.
65k now on home rebuild. Orig lasted 185k. Still original 6spd and diff. 2007.
E shaft and Stat Gear bearings from original engine. Also front iron from orginal engine. Compression mid to high 8s, all used parts except seals.
Shaft rotated approx 1.1 billion times in these bearings. Maybe more.
Last edited by kevink0000; 04-27-2024 at 05:41 AM.
That's honestly very impressive that the original bearings are being used and are in good working order. I have a Mazda reman engine in one of my 8's that lasted 30k miles before the rotor bearings failed and now the engine knocks. Makes you wonder if they even replaced the rotor bearings. Either way, very impressive on your end!
01-27-2020, 07:02 AM
