Rotary Engine build Blog

Building the Rotary Engine is all in the right tools, experience and knowhow. Get it right


10 Min Read

Rotary Engine builds | More than just apex seals and gasket set

Mazda REbuilds | Rotary Engine Shop Colorado


Keep things simple, it is all about the details, get them right and your motor will last and perform as intended.

The rotary engine is a combination of cast iron, steel and aluminum of all types held together by bolts, rubber seals and goop. If you are a lover of the rotary engine then you are one of a few. Not everyone cares to understand what makes this an amazing engine.

Looking deeper to a rebuild, it is not hard to see that having the right measuring equipment will equal a quality build.

Here we have an RX8 E-shaft and a pair of matched rotors.

What do we look for?

I look for damage to the moving parts and take special care to measure all relevant surfaces / groove for irregularities. This motor was worn out, and that is easy to see as there was exhaust getting into the oiling system. That leads to heat / soot getting into the bearings and oil passages.

When you get this far into a measurement, the necessity to get that oil / exhaust soot out of the passages is not an option. If left unchecked / cleaned, the future performance of this engine is going to be hampered. I am a fan of replacing all hoses & coolers as a build up of deposits will get back into the new engine and cause increased wear.

Remember, this motor is a volume oiled engine, up to 40% of cooling comes from the middle of the engine pumping oil through it (and the rotors) to extract heat and protect large bearing surfaces. Anything that is not clean oil is going to accelerate wear. It isn’t about spending the most amount of money you can on these motors, but putting it in places that help protect your new investment is very important.

This is also why I highly recommend a high flow Peterson oil filter before the oil cooler to protect that expensive oil cooler and for you to check and see what the filter is pulling out of the oil on a yearly basis.

I know, many will say I’ll just check the factory oil filter that will tell me what I need to know. You are wrong…the location of that filter is after the oil cooler, so because of the small turbulators and passages that make an oil cooler efficient in extracting heat, it also captures bearing material and other debris.

Rotary Engine Shop Colorado

Rotary Engine Shop Colorado

It is your car and your choice, sure it might not be an issue, are you willing to risk it? Have you ever cut in half an oil cooler, those passages are really small and capture a lot of material (packing it in tight) and reducing capacity as well as efficiency.

For a daily driver, it may not be an issue, I have seen motors not last because they overheated and had old radiators / oil coolers. It is a lot more than just a new motor. This isn’t new to rebuilds of any type of engine. Leave out the cooling system and you are already behind.

Topics:   rebuilds

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