Hi All,
I got my 8 ('06 6MT w/100k mi. original engine) a few months ago, and I was driving, just cruising on the highway (well, not highway, but going 65 on back roads in the northeast is pretty similar, and I look down, and the temp gauge is pegged. I did the best I could pulled over ASAP, but the engine still evacuated all (and I mean all, not a drop left) of the coolant everywhere. Have done all my hw, and I am going to rebuild it myself. After having done some research, I am inclined to go with the rebuild kit from Atkins Rotary (with OEM apex, side, and corner seals). I was originally going to go with OEM coolant seals, but Atkins has their "brown coolant seals" that they claim that are impossible to install incorrectly, and can take and additional 150 degrees over the stock seals. Has anyone had any experience with these or other Atkins seals? what is the consensus on their rebuild kit? I have read very mixed things about Atkins products, and even at that, I have not been able to find a ton on info on them.

 

Why did the coolant all evacuate in the first place - you'll need root cause this and fix before a new seals are added. Also what's the compression on the engine now?

 

I am not sure of the root cause, but it is the original radiator with 101k miles on it, the original water pump, the only thing in the cooling system that I had changed was the thermostat (put in Mishimoto 169 degree thermostat), so that kind of speaks for itself. I was just cruising, like I said, and glanced down, and it was basically pegged... did the best I could, but was not able to pull over for a few miles. I pulled over and had it towed home. When I did pull over, it was still running totally fine (if the heat was not cold, and the temp gauge was not pegged, I would have noticed no difference). I pulled over, and opened the hood, and there was coolant everywhere. I mean everywhere. I am not even bothering to check compression, because I know that at least one of the coolant seals is bad, so it needs a rebuild, and it was starting a bit hard before (literally exactly like this: ), and it was the original engine with 100k miles, so I am going to rebuild it, even if just for good measure and to get a fresh start (so that it does not leave me stranded somewhere again).

 

That thermostat probably isn't related to the failure but it didn't do anything other than make your account balance smaller and maybe contribute to a little extra carbon build up.

If there was "coolant everywhere" then you either burst a coolant hose or it all came out the overflow. Is it concentrated anywhere near near the overflow tube coming off the air separator tank?

If it was a burst hose, then I'd replace the hose and do a block test ($30-$40 for a kit on Amazon). If the block test comes back negative, then get a compression test. You might have gotten lucky.

If it all came out the overflow, you either boiled it (meaning you have cooling capacity issues) or the coolant seal failed near a high-pressure section of the keg (probably around the power-stroke section). Again, a block test will help you figure this out.

A 100k mile engine is very unlikely to have housings in good condition. You can try to get by with marginal housings and the engine might last a year or two but it will never have great compression and it will never make full power. Replacement housings are ~$850 each. $1700 for two housings + $1500 for the Atkins kit and you're already over the price for a Mazda reman motor.

 

Ok, good point, I kind of figured that it came out of the overflow... there are definitely no burst hoses. I think I am still going to do a rebuild, I am pretty set on that, this just gives me a good excuse to do it... I think I might be able to get some half decent housings off of eBay (I love eBay, and have only had good experiences there... I know, the possibility of a scam or bad product w/no support is a big possibility, but at least for me, the risk is justified), for about $450-500 apiece for the housings, and then like you said, $1500 for the Atkins rebuild kit. I know it is really sketchy, but I think it is worth a shot. As for everything else, my best bet is to hope it is in spec (assuming no hiccups, I will be pulling engine and tearing down on Saturday), and if not, then back to eBay it is!

 

If your time is nearly worthless to you, this might actually be cheaper.
Rebuild kit: $1500
2 x rotor housings of unknown condition: $1000
Possibly need to lap and re-nitride the irons: $200 each (?)
Bearings: $?
Rotors: $?
Eccentric shaft: $?
Gears: $?
Many hours of labor: $?

Do the tear down and measurements before buying anything. Get your entire parts list together.
If you get in there are discover things are really bad, you can reassemble it and still use it as a core for a Mazda reman.

Also, regardless of which route you take with the engine, CHECK EVERYTHING. It's so much easier with the engine removed.

• Test all vacuum solenoids (using mityvac hand pump to pull 10 psi, if it holds apply 12v across the terminals).
• Test all oil injectors (Same test as above but without applying 12v).
• Check oil injector lines for clogging.
• Send your fuel injectors off for cleaning and flow testing (I'm partial to Witchhunter Performance).
• Remove oil cooler lines to check for corrosion.
• Clean up all chassis grounds.
• Check all coolant and vacuum hoses for leaks or wear.
• A bunch of other things.

 

Judging by the results on this forum, it is nearly impossible to rebuild a Renesis to the level of the current remans for less cash outlay. Most first time rebuilders fail and end up rebuilding it again, giving up, or buying a reman. Food for thought.

 

NotAPreppie, thank you for the suggestions, I did not think of several of those points...

Steve Dallas, I have gotten that feeling, but maybe I should give a little bit of background: I am 16, and my dad decided to get me an 8 as a first car... he is pretty mechanically inclined, but knows nothing about the rotaries, especially the 8. He has clearly stated that if I do not attempt to rebuild it, then it will be no longer... I myself am very mechanically inclined, and the thought of rebuilding it myself is not terribly daunting, as long as I approach it armed with the proper knowledge, and a real lot of care...

so, yea, I might be setting myself up for failure, trying to do a budget rebuild myself at 16 with sketchy components off eBay, but even if it ends up not working, it will be a fun learning experience, and if it does, then all the better (and more fun)

 

Rebuilding is not worth it. Just get a reman and engine swap. It's far better than trying to attempt the rebuild.

 

Well, I guess the best time to learn stuff is when you're young and you don't have any financial liabilities or dependents.

Like I said, don't make any purchases until you have the engine torn down and everything measured. Make your decisions after you've gathered as much information as possible (this advice also applies to life in general). If you're going to go with used eBay housings, buy those first and measure them before buying the rest of the rebuild kit.

 

AMD,

The "caution" around the forum...consider it a right of passage...a well-intentioned welcome into our community. I've pared your above comments to IMO what's important. Sounds like you've all the essentials to undertake and do a successful job. But don't take it lightly...as you've said do your hw...read, read, read non-forum material as well. Leverage your dad, SMEs on this forum & any local rotary community. Be meticulous, and detailed in your planning & process. Not to minimize the difficulty, risk., or resources required..... , but w/ the right research, planning & process you can execute a successful rebuild and learn much along the way.

I'm 9k miles in on my first engine rebuild for failed coolant seals... on a turbo application. Excluding the cost of tools... I rebuilt my engine for ~$2300. As Preppie has said... the cost of your rebuild w/b dependent on what all needs to be replaced. Check my build thread, Curt’s Gr8t 8 Turbo Build, beginning ~ post 81 where my rebuild process is detailed along w/ a view to those who assisted me in the process.
https://www.rx8club.com/series-i-maj...-268497/page4/

Below is a comment I posted in another thread on the same topic...

All the best!

 

wow, I guess I never expected to get this much support... If I have learned one thing so far, it is that ignorance kills (engines and more...), so the most important thing is that I know what I am doing. I will be using all of the materials available to me... I am hopefully going to be pulling it apart on Saturday, along with the help of a friend, (he owns an STI, and while he is into cars, and has done much more than me, knows nothing about rotaries. I am probably not going to be buying any parts that are expensive for a while, as I have to come up with (most) of the $$$ (my dad is making me pay for most of this project, which I am kind of happy about, because then I have a bit more freedom to choose parts...), so as I have read elsewhere, and now been told here, I am first going to measure everything...

 

Enjoy the journey. I wish I could have gotten my son into a deep dive at your age. He was not interested beyond the basics, until after he moved out.

Anyway, use only OE Mazda parts on your rebuild. Atkins and Goopy and others do not have good track records in the Renesis.

Also consider using an OE thermostat. 180F is really about as cool as you want to run this engine. Do what is necessary to control the temperature ceiling and leave the floor where Mazda designed it.

 

ok, I know to use only OE internal seals (apex, side etc.), but I will not use the Atkins water seals. I will do some more research regarding the thermostat. I have read the they Renesis is happy around 190 at cruise, but with the stock thermostat, I was cruising around 205-210.. came right down to 190-195 with new T-stat...