Mildren Rotary Automotive Services

21/12/2025

Pleased to be a part of the cruise and display - plenty of quality builds from the many people in SA still producing good work.

Thanks for checking back into the channel legends — appreciate the support as always 👊Today I’m out in Birdwood, South Australia for a Rotary Christmas Crui...

13/07/2025

Who in their right mind would put "this" into "that"?

15/03/2025

Latest build I have been working on for sometime now. It's taken a while, and to get my head around the Henshaw dry sump system.
I try not to assemble anything where I have not taken the time to understand all the nuances - I figure if you don't understand it, you shouldn't be building it!
Thank you BJ for your patience, thru 'sickness and health', I'm hoping 2025 is a better year for me than last year.

Engine is 20B NA J-port, balanced, studded and aligned.

I'll try and post more in coming weeks as the project progresses.
When you see the car this engine is going into, you will be surprised at the effort the owner is going to. The plan is so crazy - it might just work!

All the best, Greg

19/02/2025

Send a message to learn more

09/02/2025

Genuine Mazda Factory Race L*D, as supplied for Group C touring cars. Has not been used in decades and only for a short time. Has been stored correctly. In good condition, no repairs required. Please note - side gears are splined for Mazda 28 spline axles, as used in 13B Rx4. Suit race or competition car. No time wasters please, low ball offers will be ignored. Call Greg 0438 153 584 or email [email protected]. I dont check FB very often.

$2,800 o.n.o.

10/07/2024

A modification that you might like to consider when getting your Rx8 engine built. You can see the internal shape of the exhaust port is not smooth and flowing. Instead, at the top it seems to have sharp edges and step-like shape as the exhaust flows out of the chamber through the exhaust port. In the second picture you can see a black build up of carbon in the std port (and this is after acid dipping heat treating!). In many engines this carbon build up is so bad, clogs up the top of the port, protrudes into the rotor area and absolutely affects engine performance, wear and reliability.

My solution is to get a dremel set, use a 1/8" carbide ball nose burr and re-shape the port by grinding all the shelf like sharp edges away. See other pic for an example how it could look. I also dress it with a small cone shaped stone bit to make it look nice.
This process might take you about 2 hours to perform.

My theory is that this modification will reduce the likelihood of carbon build up, as the exhaust flow more evenly through this area and there is no flow undercurrents in dead flow areas. Also improve exhaust flow and make engine breathing more efficient, although I doubt you could measure the difference.

I think this would be a good investment in your time, what do you think?

08/07/2024

Rx8 Engine builders, owners and those planning to have a go, here are some tips for you.

The inlet manifold from a recent engine build was probably one of the worst I have seen.
This engine struggled to make good power, the SSV valve was jammed shut, and airways were quite congested with carbon and thick sludgy gunk (yes that is a real technical word in rotary builder's vernacular).

I sent this manifold off for ultrasonic cleaning and even then as it came back looking clean, I checked it inside to find even more residual gunk. More hand cleaning was required and now I can be sure it is clean inside and out, ensuring the engine has the best chance of breathing as it should.

Don't assume if it comes back looking good, that your job is done - check it.

Of course, if you suspect your intake manifold is clogged up and you are not planning to remove the engine or manifold, don't forget you can always try decarbonising using a foam intake cleaner such AMSOIL Powerfoam (the one I use).

Good luck, all the best.

16/12/2023

Christmas Holidays clearance sale of Rotaflo mufflers.
Rotaflo (Walker made) Resonator RFR 200
Length 450mm
OD 89mm
Bore 50mm
Priced to clear $50 plus postage. Call me Mob. 0438 153 584

16/12/2023

Christmas Holidays clearance sale of Rotaflo mufflers.
Rotaflo Resonator RFR6 250
Length 310mm
OD 150mm
Bore 63mm
Priced to clear $90 plus postage. Call me Mob. 0438 153 584

16/12/2023

Christmas Holidays clearance sale of Rotaflo mufflers.
Rotaflo Resonator RFR6 300
Length 310mm
OD 150mm
Bore 76mm
Priced to clear $90 plus postage. Call me Mob. 0438 153 584