On one of our current Rx8 builds, the car came in not running, a common occurrence. Our job is to make sure that what ever caused this to not start / run properly doesn't happen again.

On this motor, everything looked ok, until we got to the internals.

Every rotary engine that comes apart tells a story of what happened and we want to find out why it happened. Experience and details matter. When we remove the motor, the details present the story.

As we pulled the motor, removed the intake, wiring harness, lines and all that surrounds the block, the story came together. 

On the first impression, the oil ran hot for some time, the inside of the front cover all shiny gold in color means that this ran hot for some time.

Next, was the fact that the seals all fell out when we pulled the rotors out, they themselves didn't want to come out easy, the rotor bearings were spun on both rotors, this I haven't seen for a long time. Oil cooling will be addressed, for this writing, it is about rotors and the bearings.

The second clue was that the surface material of the bearings was not worn hard on any one side, this indicates that the engine load was minimal. I finally got the driver of the car to reveal what happened.

Sure enough, they were reving it in neutral allowing it on decel to pop and snarl as rotaries do, what they did not realize that the while the rev limiter is active just over 9000 rpm, the motor over-run (or its ability to spin freely) does not have a preset limit and can easily hit 11-12000 rpm shaft speeds, these motors do not do well with that type of abuse.

The over-reving caused the rotor bearings to tear themselves up trying to stay locked in place while the rotor itself spun (at ⅓ shaft speed) over 3000 rpm. Motors do not like that, they can handle a couple of over-revs, just not that many. The motor refused to start at all after several days. 

Why check the rotors for cracks? Oftentimes, situations demand checking vs. assuming. We want to make sure that our builds are done properly, when we sense that they have been over-stressed, it is better to be on the safe side and have that done. Since we didn't have any current Fluorescent dye penetration liquid, having quality relationships with our neighborhood businesses matters.

Just right down the lane from us, JP's Garage LLC, offers quality repair services for cars 1996 and newer. I wanted to elicit their crack checking services (like what you do for a head that needs machine / repair work). It is always good to work well with your neighbors in a business like ours, serving others.

They have a solid process and we had them back in a couple of days, checked and passed inspection. 

Off to the ultrasonic cleaner for one last pass before we start rebuilding with new seals, springs, oil control rings and of course new bearings / E-shaft. The pressing in of new bearings is another action we do that ensures that there is no damage to the rotors, if the bearings just drop in, then they have outlived their lifespan and need replacing. Details matter.

Like I tell every customer, we want to only see the inside of your motor once, so we take the extras steps to ensure a quality motor build. 

Not every motor is going to need to have the rotors cracked, we inspect how the motor comes apart and measure carefully, our experience comes into play when making these decisions. I am a firm believer in having a proper checklist to do things right.

As our business continues to thrive, we want to support our local businesses, please check in with them if you need any of the following:

JP's Garage: Professional and Affordable Auto Repair in the Frederick, Erie and Dacono Colorado area. 
- Tires
- Transmission Repair
- Diesel Repair
- Gasoline Repair
- Steering & Suspension
- Brakes
- General Maintenance
- Cooling System Repair
- Accessories
- Heating and Air Conditioning
- Electrical 
- Lift Kits
- Gas Direct Injection Service
- 1996 & Newer

Every rotary engine rebuild deserves to be built correctly, details and process matter. Connect with us.