Cooling System Mods

[Barry Bordes]

Some thoughts on improving the cooling of the rotor housing in the area of the spark plugs to minimize heat distortion.

Let’s go back to my previous engine failure.
Whenever an engine is disassembled I do a failure analysis (an old habit of mine from working on helicopter turbine engines for a large oil company) and attempt to determine the Root Cause.
Sounds so simple but like they say,” the devil is in the details”.


So first we have the broken apex seal. The very common type failure with the apex seal chip imbedded in the rear rotor and it gouging the housing.

Next we have the cracks at the spark plug holes and lifting of the apex seals in that area.




Add to that chafing of the side plates to rotor housing interface that same spark plug area.




At this point we have two contingents drawing different conclusions. One thinks we should secure the area better with dowels and or studs. The other group thinks better cooling of the area is appropriate.

I started looking for 3 studs to reinforce that area. In my search for studs and reamers I contacted Carlos Lopez. He changed my direction.

Carlos thought that creep was a symptom but not the root cause. The problem was high heat and low water flow in that area. He mentioned that the 3rd gen pump was one of the poorest designs.

Kenichi Yamamoto's book shows the temps around the plug area.







My thoughts then went to 1-A better water pump (Mazmart) and, 2- Porting the rotor housing in the hot spots as shown above.

Barry