I will give a 'verdict' in conclusion type post later on. I've enjoyed this process and will be open to doing similar again in the future. I want to thank you for offering yours as an example for others in discussion on an open forum and thank you for considering us for your purchase.

I've worked as a tech at more than one Mazda dealer myself and have nothing against them or Mazda North America. I tried to do the best work I possibly could and that did not lend itself to earning what I needed (Maybe I'm too meticulous) as I'm not one of the quick techs. I am thankful to Mazda and Mazda North American Operations for many things including giving us the cars we enjoy. I also think some people should find a good dealer and get to know the techs. Don't take it for granted that you'll get good honest knowledgeable service anywhere. It's all about relationship after you've done your homework in finding a place that knows what they're doing. By doing so, you'll have people paying extra attention to you and your vehicle. I'm also a fan of many great and talented Mazda independant shops. It's all about doing your research.

Paul.

 

Too funny .

Paul.

 

There are two thermostats - one in each oil cooler. You'll get about 10 degree warmer oil temps.

 

Right but warm-up will not be accelerated.. Oh well.. Someone should come out with a heated oil pan

 

What I meant was it leads to is the breaking point of the liquid which if reached and/or exceeded, it would degrade the liquid's role.

 

The final assessment is: There was oil leakage from various locations including (It appears) the oil-metering pump O-ring. This seems to have been caused by relatively high oil temps over the course of many miles. Water temps being elevated in regions of the motor would possibly also have influenced this. The front main oil seal that was originally blamed for the smoke did not appear to be bad. Most likely the oil leaking from the metering pump may have gotten on the exhaust manifold.

Here’s the break down on individual parts:

Apex seals- Normal wear, ridges in their sides due to rocking back and forth, some distortion in the middle and wear on the ends. Too worn to re-use.

Side seals and springs- Normal wear on seals and springs. The clearances are too excessive for us to re-use and the springs are too warn to re-use.

Corner seals and springs- Normal wear. There are the indentations from the wear of the side seals constantly colliding with them. We would re-use neither spring nor seal.

Cut off seals- Were in reasonable shape

Oil seals- Casings are in good shape. O-rings aren’t too bad. They were very typical in being hard, squared and a bit brittle. The springs were good. We re-used the springs and the casings only.

Rotor housings- Very little shrinkage (79.99mm) was present. Excessive wear on chrome surface due to apex seal condition. Excessive spark plug distortion (Leading plug holes) and excessive cracking due to high localized temperatures at some point. This may have been partially due to water cavitation whilst at the race track. We would not re-use these housings.

Flat housings- Very good shape. Very little wear. Probably due to pre-mix and good quality oil.

Rotors- Decent shape although a lot of carbon was present. Possibly due to level of enrichment of air fuel ratio, a little too much pre-mix.

Bearings- Rotor bearings were good enough to re-use. Stationary gear bearings were not re-useable due to excessive wear. This would be caused by the oil layer being too thin to cushion the shaft in the most critical areas especially the front of the shaft. This becomes exaggerated at high engine revs. The wear was all on the load side of the bearings.

In summary: This motor could have kept on running for 10s of thousands of miles without much problem. Some minor things could have been done differently in maintenance. I would back off the pre-mix by one ounce per gallon perhaps. Our water pump is imperative to any one who runs prolonged high rpm. It will enhance the longevity of the rotor housings. We recommend a higher viscosity of oil for bearing protection (30, 40 or even 50 weight). The reason I said 10W40 is because it meets most peoples needs here in North America. I have nothing against 5W or 0W except that those who don’t like synthetics could be using oils with more VI improvers to achieve my recommendations, which becomes a problem with hard driving and long oil change intervals. As for cold start and driving techniques and their relation to bearings and oil: I like to drive almost immediately in order to put gentle load on the motor. This is done in order to have less time in what I call ‘Fast idle enrichment mode’. The engine warms up quicker and suffers less from fuel dilution of the oil. The emphasis is on ‘gentle’. That being said, I won’t argue with those that suggest that the oil temps are too slow to normalize since I haven’t tested this myself. A good rule of thumb is: Never accelerate hard on a cold engine.


Paul.

 

Here's the finished product. Ready for a new home.

Before anyone mis-understands me: I recommend 0W,5W or even 10W to most people with the viscosity being at least 30 weight. My general recommendation is 10W40 in a quality synthetic but it's up to the individual to decide whether syn is for them. If you're racing one of these, up to 50 or 60 weight would be even better.

Paul.

 

Thank you Mazmart for the detailed post mortum and thank you Expo1 for the engine. I'll be at 100k in a few months and it sure is nice to know what to expect... and where I can get a good rebuild when it's time.

 

My pleasure and thanks for the comments.

Paul.

 

great write-up Paul! Can't thank you enough for all that you're doing with this project

 

I'm sorry. Could you repeat that? I seem to have missed that part!

 

sounds like I will be selling my 5w20 oil. Thanks to everyone who contributed to this. This is such a great site and a awesome thread.

 

Thanks Paul, while hearing I could have driving some more on it gives me mixed feelings in the end myself, and the RX-8 community have been helped.

Expo1

 

very true Expo, never fun to hear that you spent the $$$ prematurely BUT it was only a matter of time before more problems surfaced. Better to be proactive and ensure you keep on Zoom Zoomin'

 

Expo1,

It's been a pleasure dealing with you. You're a quality person and an asset to the community.

Paul.

 

+ a million.. Thanks to expo1 for volunteering up his engine and to Paul for taking the extra time to provide public feedback!

 

I agree, and this is a huge contribution to the RX-8 community, so thank you Expo and Paul!

 

Here are the apex seals for those that would like to see. By the way, if your engine builders hands don't look like this he can't be any good

Paul.

 

Hey Paul,

So now that expo has his new motor, the thoughts turn to how he should break it in. I know plenty of people believe in the baby it for the first few thousand mile school of thought, but there's also an argument for breaking it in hard. What would you recommend?

We all know what Fred would recommend...

 

This awesome... big thanks to Paul for the awesome write up.

Leaves me with one question though: If people were to go with your recommended 10w40 in a quality synthetic, what quantity of premix would you recommend to go along with that?

 

I already have 3,000 miles on the new motor so break-in is over. I just followed the standard take it easy to 600 mile thing. AS for the pre-mix amount I was adding about 4oz of Idemitsu to 13.5 gallons of fuel. I will know it down to about 3.5. One thing about the Carbon / Pre-mix issue. The one thing I noticed right way when I started to pre-mix was the reduction of tail pipe soot. Did that soot end up becoming the carbon that was around the exhaust ports?

 

I'm going to be difficult and say, moderately. His should have used rotor bearings (That are already broken in) although it will have new apex seals. One thousand miles max.

Paul.

 

Those apex seal pics really support my hypothesis that the engine does either need the 3rd oil injector or some form of premix. Look at where all the wear is!!! It's all in the middle. The outsides, where the oil injectors spray, is where the least wear is.

How often did he run premix? I know he used it for track events but did he always use it on the street too for the engine's entire life?

 

Started to premix at 60k IIRC

expo - that "less tailpipe soot with premix" thing always puzzled me. The first thing I thought when I saw those exhaust ports is "oh, that's where it all goes"

 

I've never had less soot with premix. If anything, I have the same if not a little bit more soot when using premix.