F.A.Q.- Frequently Asked Questions

The following are typical questions or comments.  If any of these describes your situation, follow the appropriate link for an explanation and images

 

Why did I lose power all of a sudden/Why did my engine stall? 

My car ran fine not too long ago and now it won't start; what happened? 

I parked my car last fall and I can't start it this spring; any suggestions?

I see smoke every time I start the car in the morning; what could it be?

I'm losing coolant and I can't see where it's going

I'm losing engine oil and I can't see where it's going

I can see engine oil or coolant leaking around the engine

How can I get more power from my engine?

Can I use synthetic oil in my rotary engine?

 

 

Q. Why did I lose power all of a sudden/Why did my engine stall?

A. Sudden power loss is by far the most catastrophic of all failures.  This typically suggests that an apex seal has failed, most likely a function of mileage and carbon build-up.  Apex seal failure is characterized by sudden fracture due to shearing and bending stresses.  Often times, this will occur at lower than usual mileage and this is affected by prolonged vehicle storage and carbon build-up.  Carbon build-up prevents free movement of seals and springs.  Sadly, those who choose to store their vehicles for prolonged periods of time are often the ones who experience premature engine failure.  Sudden power loss could also cause an idling engine to stall and fail to start.  At that point, it is presumed that an apex seal failure has occurred.  Power loss can also be a function of a clogged catalytic converter, which invariably affects engine performance and may lead to catastrophic failure in a weak engine.  Inspect the catalytic converter or have a reputable shop perform the work.

Older 2nd generation RX7's may behave as if the engine has failed if the solenoid resistor is burned.  This is a relatively inexpensive component and is located under the air cleaner box on the passenger side on 86-87's and some 88's.  The resistance must be checked against the specifications outlined in a Mazda workshop manual or equivalent literature.

  This is an image of a rotor tip with a failed apex seal.  The groove is almost always destroyed when the apex seal disintegrates.  The amount of carbon on the combustion faces of the rotor is typical of an engine with progressively lower compression.  Depending on how the apex seals disintegrate and get swept out through the exhaust port, pieces may become lodged between the sides of the rotor and side plates.  At that point, it may become virtually impossible to salvage the majority of engine components.

 

 

 

 

 

 

 

 

This is an image of a damaged rotor housing and it represents the most probable type of damage.  Apex seal failure is also a result of the relative contact angle between the apex seal and the rotor housing.  At a certain point, the apex seal is no longer normal (90 deg.) to the rotor housing surface, which results in increased bending stresses.  Increased material galling is evident in the power stroke region shown in the image to the left.

 

 

 

 

 

As the broken pieces are swept around, they're being forced out the exhaust port.  In doing so, they cause more damage.  Turbocharged engines run the risk of turbine blade damage when this type of failure occurs.  It is good practice to inspect the exhaust system from the engine to the first catalytic converter, to remove any trapped debris and to replace any damaged component.

 

 

 

 

 

 

 

Q. My car ran fine not too long ago and now it won't start; what happened?

A. This type of problem is potentially less costly and it may be possible to revive the engine.  Depending on the nature of the failure, there is a possibility that some of the rotor seals may have collapsed due to carbon build-up.  This is typical of a high-mileage engine, one with a fuel management or one with an oil consumption issue.  First, it should be determined which of the three conditions apply.  The following technique can be used to revive a freewheeling engine, presuming that the rotor seals are simply collapsed and not damaged.  It is important to note that, long term, a high mileage engine will continue to freewheel or lock up and the most practical remedy is to rebuild or replace the engine with a rebuilt unit.  A low mileage engine, which is overcome by carbon repeatedly, requires immediate attention before catastrophic failure occurs.  A reputable service station experienced in rotary engine fuel and oil management systems must be consulted.

1. Remove EGI fuse; move the vehicle outside if not there already

2. Remove both trailing spark plugs.

3. Prepare a 1 L (1 qt.) mixture of 3 parts kerosene and 1 part automatic transmission fluid.

4. Attach a 19mm socket to the eccentric shaft pulley bolt.

5. Using an appropriately sized hose and a funnel, pour a little fluid into the one of the rotor chambers.

6. Work the engine back and forth 1/3 revolution at a time.

7. Use ½ of the mixture to uniformly soak up the first rotor.

8. Repeat steps 5-7 for the second rotor.

9. In most cases, after using 1 L of this mixture, both rotors should be adequately soaked to free up stubborn seals.

10. With the EGI fuse removed and the trailing spark plugs removed, crank the engine for 15 seconds to evacuate excess residual kerosene mixture.

11. Perform a compression check with an adequate compression gauge (a standard gauge provides good results if the check valve is removed)

12. Repeat steps 3-11 if the compression is still not above 6.1 bar (90 psi)

13. Reinstall spark plugs, wires and EGI fuse; with vehicle outside, attempt to start engine

14. If the engine starts, run it to operating temperature and shut it off.

15. Check compression again and compare to the value obtained in step 11 or 12

A healthy engine should maintain good compression for a while after this procedure.  It is good practice to check the compression on a regular basis, as this is the only indication of what is happening inside the engine.  If the compression slowly creeps below 5.0 bar, it is definitely time for a rebuild, which is the only way to adequately remove all the carbon build-up under and around critical seal springs.  The above method has been proven to provide positive results in a good majority of situations.  No guarantee is implied or offered and it is recommended that the above steps be performed by a qualified technician who is familiar with rotary engine fuel management systems.  Rotary Dynamics is not responsible for personal or property damage resulting from improperly following the above steps as well as improperly following service procedures as outlined in the Mazda Service Manual.

 

Q. I parked my car last fall and I can’t start it this spring; any suggestions?

A. This type of problem is very similar to the above situation.  Refer to: My car ran fine not too long ago and now it won't start; what happened?

 

Q. I see smoke every time I start the car in the morning; what could it be?

A. There are two types of failures which could be characterized by smoke coming from the exhaust:

1. If the smoke has a blue tinge and dissipates after a short while, it is an indication of slight oil consumption, which is somewhat normal and typical for these engines.  If smoke is visible, it is recommended to monitor the engine fluid levels on a regular basis to determine where the loss is.  Excessive blue smoke indicates a serious oil burning issue, which will invariably result in carbon build-up and premature engine failure.  In some cases it may be a function of a malfunctioning oil metering pump, or a seized metering pump rod linkage (pre 1989 models).  If the oil metering pump system is found to be functioning properly, the oil control ring seals may be allowing oil bypass into the rotor chambers, which could be rectified by rebuilding or replacing the engine with a rebuilt unit.

2. If the smoke is white and persists for longer than a few seconds and appears to move away from the vehicle like a small cloud, it is an indication of an internal coolant leak or coolant bypass from the coolant galleries to the combustion chambers.  This may be a result of overheating, which could cause the rotor housings to warp or the coolant seals to fail.  This may also be an indication of an internal crack or housing material corrosion resulting in fluid bypass, which tends to occur in engines with high mileage.  This could be rectified by rebuilding or replacing the engine with a rebuilt unit.

 

Q. I’m losing coolant and I can’t see where it’s going?

A. This type of failure is very similar to the above “I see smoke every time I start the car in the morning; what could it be?”  This may be characterized by internal coolant ingestion if the leak occurs around the intake side of the rotor housing, or it may be characterized by compression gases displacing coolant from the system.  The latter would soon result in overheating and subsequently in rotor housing warpage.  This could be rectified by rebuilding or replacing the engine with a rebuilt unit.

 

Q. I’m losing engine oil and I can’t see where it’s going?

A. This type of failure is very similar to the above “I see smoke every time I start the car in the morning; what could it be?”  When engine oil is burned in small amounts and efficiently, it may not be apparent if there is no smoke coming out from the tailpipe(s).  Make sure that the metering pump is functioning properly.

 

Q. I can see engine oil or coolant leaking around the engine?

A. Engine oil or coolant can leak from many places, but the leaks to be primarily concerned about are the leaks from between the rotor housings and side plates, as those cannot be repaired without a full engine rebuild.  Other typical leak paths are the front and rear main eccentric shaft seals and the oil pan to engine block interface.  Also investigate for oil and coolant leaks around the turbocharger, oil cooler and radiator.

 

Q. How can I get more power from my engine?

A. Base stock configuration adequately balances power, fuel consumption and exhaust emissions.  Common engine enhancements include what is known as porting and polishing, which is a process by which the intake and exhaust ports are carefully modified in order to alter port size and duration.  Common porting levels have been established, ranging from mild street porting to monster porting.  As power increases, engine durability and reliability decrease and therefore careful consideration must be given to any level of modification.  As with any modification, it is impossible to only modify one characteristic without affecting the entire system.  Therefore all modifications must be carefully planned based on ultimate goals.  Turbocharging and supercharging are also options, which provide further power gains.

 

Q. Can I use synthetic oil in my rotary engine?

A. There are many opinions and just as many people who express them.  Some are for and some are against the use of synthetic motor oils in rotary engines.  Neither camp can provide compelling information.  Generally speaking, synthetic oil is not entirely harmful, but the combustion process does leave a residue, which is harmful to the internals of a rotary engine.  After consulting with chemical engineers and experts who are intimately involved in synthetic oil development, the use of synthetic engine oil was given a solid thumbs down.  Synthetic oils consist of a PAO (Poly Alpha Olefin) base stock, blended with Esters and Diesters to attain the desired characteristics.  The problem arises when the PAO stock is subjected to the combustion process.  This process is unique to rotary engines due to their oil metering system which injects oil to lubricate the apex seals.  The residue is a hard carbon-like substance, which tends to harden and become glass like in certain areas.  Once this residue makes its way on and around critical seals and springs, the engine fails due to seal collapse or apex seal breakage.  Upon disassembly, it is always evident that synthetic oil was used, by the contamination on the rotors and the severity of the damage.  Frequent oil changes with a high quality mineral oil of the proper grade, will provide a great deal of durability and reliability.  It is therefore our recommendation to stay away from current synthetic motor oils.