Footman

iTrader: (2)

Yours show 283 rpm.
Every car cranks at a different speed depending on the condition of the starter/battery system.
That's why values need to be normalized for 250rpm because if your data came from cranking the car at a higher RPM, it is going to return higher compression values.

boffam

iTrader: (1)

Could the cause of the low compression be diagnosed from the teardown?

Is it at all possible that the compression numbers are whack, given that your car ran pretty well? I would have been curious to see dyno numbers. I wonder how much a certain decrement in compression influences engine output?

Anyways, a supremely interesting thread...your attention to detail is impressive.

shadycrew31

iTrader: (6)

I will bet $5,000 that his compression was low due to side seal shrinkage.

Footman

iTrader: (2)

What do you base that claim on?

Footman

iTrader: (2)

Also after reading on a lot of oil threads, it looks like in Toronto's climate where winter can have those odd cold days where it's -20 C, and in the summer some days are like 36 C, it makes sense to run 10W30 in summer, and 5W30 in winter. And of course premix Idemitsu all-year round.

I can see that if I was driving the car leisurely like nothing over 5k rpm.... literally only doing ONE REDLINE a day..... I could see why the recommended 5W20 or 5W30 would work fine. But I am not that type of driver, and perhaps if you are also a spirited type of driver that drives the car the way it's meant to be driven... you might fare better with what I am thinking of doing.

shadycrew31

iTrader: (6)

The fact that you didnt have extremely low compression, most low compression that I have found is form side seal shrinkage. if an apex seal breaks thats a whole other story.

Considering sideseal specs are gapped wider than a podunk hick's front teeth. It doesn't surprise me that this issue comes up all the time.

Neo

Nice! Having the CX5 in the dealership is always a big plus. They gotta start receiving trucks by now if they expect to have them on the road officially by March 1st.

As I said before, this is a stressed 1.3lt rotary engine. Getting 90-120k out of the engine during normal driving duties is expected. Anything above and you're lucky to have an engine that is going strong.

At least you'll be happy with the new engine.

scottish

iTrader: (1)

+1 with shady on this one .

With your **** maintenance program you follow, oil is not to blame for the cause of your engine failing a compression test in this case. Poor side seal clearances or carbon build up is the problem.

With your driving style as you put it, daily driven, stop and go traffic, highway driven and red line a few times a day all cause excessive carbon build up. Believe it or not the few red lines a day that you do creates way more black soot or carbon if you like than sitting in traffic.

What burns carbon off is heat, not a few red lines a day or the two parade lapping events you do a year. Throw some premix in the tank, and take your car lapping for a few hours at the track and this will generate high heat burning off the carbon also high RPMs increase OMP injection for fresh oiling of all the seals. Doing this is better than seafoaming or decarbon at the dealer plus you have fun at the same time.

I have just pulled a rotor apart from an fd that dropped an apex seal and trashed the housing. this thing was choked with carbon build up about 1/64th thick on the rotor surface. corner seal, side seals are intact no abnormal wear but did notice one of the side seals was sticking and on the flip side of the rotor, one end of a side seal was stuck compressed in and the other end was free. took some time to free it up with brake cleaner once i got it out check all springs are good.

So five pages of trying to find a new super oil plan is not going to stop your motor from failing again.

That engineer brain of yours is over thinking things again. Forget that oil is the problem and accept that poor build quality and carbon build up is the enemy of all rotary engines period.

a red line a day does not keep the carbon away.

Be happy your getting a high quality reman unit built from bits and bobs left over from other failed renni’s and be glad you took the extended warranty program.

Footman

iTrader: (2)

So how do you maintain your engine Scottish? A lot of what you said is contradictory to what a lot of other people have said for ages as well. I'd like to know your maintenance routine.

Footman

iTrader: (2)

I don't know how to embed youtube into here so I'm just gonna post the links. Can someone teach me?

http://youtu.be/sw4CYYgoj_Y

http://youtu.be/bV_3ByWV-bA

shadycrew31

iTrader: (6)

Wish you could crack it open and have a look, I'm still betting $5,000, that if you put a feeler gauge in between the side seal and corner plug it will be waaayyyyyyy out of spec.

As Scottish said, its a rotary thing!

I had that same amount of oil buildup, in my engine as well... In fact most engines do.

9krpm came to the same sad conclusion that there isn't **** you can do to prevent carbon buildup. Its just the nature of the beast.

when you add lose side seal clearance and nasty amounts of carbon you get stuck everything and low compression.

01Racing

So using a heavier grade oil and premixing will solve that oiling issue lol. Sorry just had to add that lol. Here is the real bottom line, so be prepared. Mazda went the route of trying squeeze former turbo horsepower from a NA engine. They also chose to run race style RPM and had to make all the seals lighter and smaller in doing so. You can't expect or ask a 80 cubic inch engine to produce 2.87horsepower per cubic inch and live for a very long time. The older 13B's had big heavy seals in them and really only revved to about 7-8K, thats why many of them went into the 150-200,000km range or more. Lets not forget that those engines also only produced 170 horsepower at the max. The reality is these renesis engine really have a life expectany of probably up to 100,000 miles at best. I am sure the odd one will live beyond that, but the majority are failing at around 60,000 miles or 100,000KM.

bse50

Bullshit.
Side exhaust ports and crappy side seal clearances and poor OMP programming is what killed most of the early engines around that mark.
All the engine that I tore down and that used anything between 5w30 and 0w50 didn't show excessive apex seal wear for the mileage.
The engines that used 5w30 oils and did a lot of stop and go traffic had a lot of bearing wear, one who used the same grade but had a better oil pressure regulator didn't.

In short... what worked for the previous gen 13b family doesn't apply here.

01Racing

Exactly, hence why the renesis blows up and the old ones didnt. I take it from your statement that you can reassure those who own say a 2009 or 2010 wont have any engine issues?? lol

Okay lets look another perspective, I am bored today and this kind of time lol. A pinnacle of V8 engine engineering, a 358 cu in Sprint Cup engine unrestricted can make say 900hp and car turn almost 10,000rpm! These engine are built with the kind of money and engineering most of us will only ever dream about, they are truly state of the art in pushrod engine building. They make 2.51 horsepower per cu in (less than a stock RX8) and have a life expectancy of about 8- 10 hours before requiring a complete rebuild. You get the point I am making?? lol Or we can look at real serious horsepower, NHRA Top Fuel, Supercahrged etc 472 Cu In @ 8,000+ horsepower, 16.9 HP per Cu In, life expectancy including warm up and burn out? 4 Minutes lol.

bse50

Who owns a s2 will have much less problems, not sure about side seal tolerances though.

Neo

As I stated before.. these little engines are stressed. It's in their nature to be stressed.
Can't expect it to go 400k like your typical Crayola or Civic. It was never designed to do that.
It was designed to be in a sports car.

What we need to see is some serious engineering of future rotaries. These little kegs are fantastic at what they do. But they have to evolve just like their piston counterparts.

Lets hope the 16X pulls through development.

Iluvrevs

Spin, I will post more thoughts in my analysis of the UOAs with regard to conversations here in the UOA section to help keep things more organized.
But, you are getting what Im saying as I meant for you to.

RXeckless

iTrader: (5)

Been watching this thread since the start, and I could not help myself.
Wow, it about time we really got around to what killing the renesis engine. Said & done, now back on to what really matter on the 8 forum, what is the best car wax!
I still like Mothers Carnauba Wax myself. Man, sometimes I can be such a *******!
Poor side seals bingo! Carbon build-up bingo!
I've seen build threads with less pages, free new reman, stop over analyzing it. Renesis engines are not the only engines that fail, live long and prosper.

01Racing

Dude, they need some serious cash to stabalize Mazda Japan before they spend on R&D etc. Last I read they were 14 Billion in debt! I read they are actively seeking partners, looking to an additional share offering, anything to get some working capital.

01Racing

What?!! Your waxing your a____hole lol???? ahahahahaha

G_ man

iTrader: (2)

well after reading all of this, I will do what I have been doing from the start.
Keep up with all regular maintance, drive like I have been(a guy in his late fourties)
And be glad I got all the warranties even the extended ones
Life is life, just have some fun before you check out.

Glen

RXeckless

iTrader: (5)

The waxing ******* agrees!
So hold on to your Mazda rotaries, I don't think I'll see a new one in my lifetime, some of you young guys might. The 16X is a pipe-dream in today's economic / environmental hole we dug ourselves into. Hopefully the Germans will take over where Mazda has left off.

shadycrew31

iTrader: (6)

Ehh I put in a rotary rebuild as the equivalent to a timing belt change. Every 60k pull the engine and rebuild it! only costs about $1300 if you do it yourself.

scottish

iTrader: (1)

there’s nothing routine about my maintenance. My 8 isn't my daily driver and it all varies on what I’m doing. last season I was changing oil with dino, what twice a month i.e. before I went to track. Also top up at the track, I was burning just over a qrt each time plus premixing at the track only. Then once in the winter months. Heck I think I put on 5k km last year if I’m lucky and the majority of that 5K was all too, on and from the track.

as for contradictory how many of these people that report their engines failed on this forum are weekend warriors tracking their cars or are dd with the same driving habits as you? I would say more like your driving habits.

I was at a buddies place who is a builder and races rotaries and what I seen there was interesting what he had going on. Endless daily driven or babied kegs just choked with carbon and his race engine from last year’s season clean as a whistle but his omp was missing even said the omp was a waste of time as it can fail with no warning or the oilers clog up so just delete it and premix only then there’s no reason to worry about if the seals are getting enough lubrication.

judging from the pics and vids of your intake runners all gummed up I would bet your side seals are just as bad also in the vid it looks like they disassembled and cleaned the lim before you got to video it but put the dirty sleeves back on it. Hope they cleaned them before they put the lim back on the fresh keg.

I wouldn't bother wasting any more time trying to find alternative oil because putting in synthetic, isn’t going to stop an apex seal or side seal failing due to carbon build up. Maybe it will give you better mileage and better bearing wear but only if you put a SOHM adapter in so you can put 2 stroke oil through the omp.

The renni is weak for daily driving and mazda know this and that's why the extended the warranty period.

I would put a catch can on it straight away and stick to the spec oil for the remainder of the warranty and be happy.

van

iTrader: (2)

^ Highly recommend the catch-can. When I got my reman engine installed, it dumped a bunch of oil into my intake after a month.