This is from an RX-8 owner in the UK who has done 58,000 Miles, he suffered an Engine Failure and decided to pull RENNY apart,
what has been revealed are the usual Stationary Gear Bearing wear, badly worn Apex Seals which damages Rotor Housings
(look at the middle scour marks from no oil). Spark Plug hole cracking.

In the interest of not "upsetting" our touchy UK friends I won't include the link.

I have included some of the pics he posted and all his comments.

Interestingly he used only Fuchs XTR 5W-30 engine oil (which would be a semi-synthetic).

 

Hi everyone,

My RX 8 engine failed, so i decided to pull it apart to see whats gone wrong.

Well the bearings are knackered the rotor housing look shot!!! The apex seal's are heavily worn!!. One of the rotor housings looks like it has a crack in it by one of the plug holes.

Just looking for opinions on the failure and the causes and what i can do to prevent it.
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Hi guys

The car (2004 model) did approx 58k always serviced on time and i checked my oil regulaly the most i ever need was 3/4litre to bring back up to max. I used Fuchs XTR 5w-30 for servicing and top up. The only real problem the car has had is a missfire at 45k approx and it ended up needing coils plugs and leads. It never overheated or had any other problems.

Thanks

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Interesting - prolly need more history before you blame the oil ...

 

hmm guess me premixing is a good thing

 

The rotor housing wear looks to be from improper oil metering which reaffirms my belief that pre-09 engines need to premix. It is this wear that the new oil metering system on the '09's was meant to fix.

The bearing wear is most likely from poor startup lubrication.

 

this I need to start doing

 

Yeah more history would be good. But if he did change it properly and there is nothing else scary about it then that's pretty scary.

Interesting.

 

I met up with a few young rotor heads the other night and they were doing burnouts without even warming up their motors properly . Not to say this guy did that sort of stuff but unless you know the history who knows what that engine was subjected to .

 

I agree RG...

The wear in the centre of the Rotor Housings is very clear that little to no oil was lubricating the Apex Seal, also interesting to see how well the outer Oil Injector/Dribblers lubricated the outer Apex and Housing, very smooth and clean looking apart from the usual marks on the extreme edges.

The Bearing wear is severe.

Yes, Pre-Mixing is definitely in order, but tell that to the British.

 

Aren't you suppose to use full synthetic and not semi syntheic ?

 

The guy appears to be an enthusiast, also restoring an S124A RX-3 (12A), appears to be fastidious in his maintenance and car care.

 

5W30 is the recommendation in the UK and it is also Mazda UK's (Distributors) usual warning not to use "Synthetic" engine oils only mineral.

But as we know I know of no engine oil that is a 5W that is not a semi-synthetic as I understood that 10W or a 15W is the lowest they can go with ALL mineral?

 

Yes it is, the guy did say..."The car (2004 model) did approx 58k always serviced on time and i checked my oil regularly the most i ever need was 3/4litre to bring back up to max. it needing coils plugs and leads. It never overheated or had any other problems."

Not sure on what extra/more history would help....

 

premix ftw!

 

That sounds pretty good. What are the ambient temps where he lives I wonder? I have been to England but only in the summer. Does it get really cold there?

My family gets so annoyed with me because I have to warm my car up fully before I go anywhere if its been sitting.

 

its pretty obvious that the housing wear came from lack of lube at the center. premix helps that.

the bearing wear ... blah. I dont want to upset anyone anymore. everybody has their own beliefs, yes? no ?

 

Come on nycgps, you know you wanna scream 90W90 diesel oil.

 

Hey man... I don't think anyone (certainly not me) are trying to upset any of you guys.

I thought it would be good to see a Renny stripped from another country that uses a particular grade of oil...

We don't get to see that many RX-8 engines in pieces and most of the "issues" are pretty consistent.

I am not sure about "poor start up lubrication" as everything being equal why are we seeing this wear in bearings.
The FC RX-7 has the same Rotor Oil Pump, same By Pass Regulator and pressure, same rotor bearings and this wear is not usually seen at this mileage, the only thing that is not the same as then are the oil viscosities.

Yes, we know why we see the Apex Seal wear, it is because of Mazda's STUPID Engineering decision not to include a Middle Rotor Housing Oil weeper, when they have done so in every other Rotary with oil injection.

PEACE

 

Here in the uk our oil drain intervals are every 12k, i wonder how much of an effect this has on the quility of the oil, i change mine every 4 k as i don't like burning dirty oil nor do i trust the 12k service interval.

Dave

 

I was thinking to tell them to use 0w10 ...

notice that when "proofs" like these saying that the recommended oil weight is a joke, all the "anti-going-against-Mazda's-recommendation" zealots never shown up ??

IN this case, things are even worst, 5w30.

Wear down to copper ... not good ... at least not at this mileage.

Damn I love that 20w50 smell ...



12,000 Kilometer is about 7500 US Miles. which is the same as what Mazda USA "recommend"

 

Sorry nycgps i ment 12000mls,here in the uk most cars run extended service intervals for the fleet buyers, also our early RX8's came with colder plugs than the USA, we had an 8 for our leading plug rather than a 7, which i'm sure won't help against carbon build up, plus longer warm up times.
I premix and use bg44k to keep things clean and well lubed, i'm not one of those touchy brits though lol but i know where Ash is coming from.

Dave

 

It's good to see info like this but again I think we are simplifying things. Not all oils are equal. But maybe looking at specific data on the "higher end" heavy synthetics? I mean does a good 0W-40 hold its thickness as well as a average 15W40?

 

I think that i can chime in, having torn apart some renesis engines in europe with that used that very same oil grade (5w30, semisynth)

That is not normal wear, both for the bearings and the housings for my experience. I saw just an engine with 70.000kms or so in that condition and that was because the OMP shaft was worn, the ecu was not updated with the new injection tables, therefore the car was not injecting oil practically at all.
The other engines were just showing the effects of the heavy traffic we have here, lots of carbon buildup and related damages but the bearings were keeping up just fine, same for the housings.
The dealers in rome often give me the engines for little money since they are no longer sending them back to mazda and have got no interest in rebuilding them. So i'm having my share of fun now!
Did this guy check up the OMP as well? this could explain the housing wear but what about the bearings?

 

I personally suspect high revving on a cold engine to be an issue. The wear all seems to be on one side of each bearing which I suspect to be the bottom. If it were high rpm wear, we'd see it all the way around.

We can't draw any definitive conclusions about the oil iteself being an issue whether it's with it's weight or blend based purely on the pictures shown.

 

<---------running to buy stuff to premix.....