In order to try something unique, I decided to upgrade my sandrail from the stock VW 1600 to a mazda rotary. The mazda rotary is a very different engine, based on the original wankel rotary engines. It doesn’t have pistons — instead it has “rotors” which spin around in a sort of spirograph type motion. Common rotary engines are the mazda 12A and 13B, which each have two rotors.
Below is a picture of the completed Sandrail, at the Oregon coast.
Since I didn’t find a real good source of information on how to do the engine swap on the web, I’ve put together this page that documents the process that I went through (right, wrong, or otherwise…) to do it.
In order to test the concept, and make sure I liked the engine, I purchased a used engine and tranny from a junk yard for $150 ($100 for the engine, $50 for the tranny). For a narrative of what it took to get the junk engine running, click here.
I also have page that describes the necessary mods I had to make to get things working.
Once the junk engine proved the idea viable, I went ahead and ordered a good rebuilt engine for a reputable builder, and the necessary adapter to connect the 12A to the volkswagen transaxle.
I also put together a step-by-step list of the process I went through to get the motor up and running.
The three most important rules about swapping out a VW engine for a higher performance engine:
- You’re going to blow out the transaxle
- You’re going to blow out the transaxle
- You’re going to blow out the transaxle
What I’m trying to get at here is that you should either have a close look at your tranny and beef up any weak parts, or be sure to be careful in how you drive the thing.
Questions / Comments / Etc — email me at sandrail@smbaker.com
Topics in this section:
- Original Rail
Pictures and description of Scott's original sandrail before the Mazda Rotary Conversion. The original engine was a stock VW 1600cc with dual kadrons. - Junk Engine
The steps necessary to take a junkyard RX7 12A engine, set it up on the bench, and fire it up. I did this so that I could get an idea of how rotaries worked before jumping all the way into the project. - Rebuilt Engine
This is the rebuilt engine that I purchased for the Mazda conversion. - VW-12A Adapter
Pictures of the kennedy adapter plate and modified volkswagen flywheel that lets you connect a Mazda 12A engine to a VW transaxle. - Step-by-Step Conversion of Sandrail to Mazda Rotary Engine
A step-by-step guide to converting a sandrail over from a volkswagen engine to a Mazda 12A Rotary Engine (RX7). The Rotary conversion adds power and uniqueness an otherwise stock VW sandrail. The guide will walk you through obtaining the necessary adapter plate, fabricating cooling and exhaust componets, electrical, etc. - Sandrail RX-7 Mazda Conversion FAQ
Frequently asked questions about the Mazda Rotary Conversion. - Modifications
Modifications that I made to disable the emissions components on the rotary engine and discussion of simplified wiring diagram to get the ingition working. - Ins Panel
This is the instrument panel that I built after completing the rotary conversion. I also discuss how to attach generic oil pressure, temperature, and water temperature gauges to the mazda engine. - Holley Kit
Racing beat sells this cool high-performance modified holley carburator kit for the 12A and 13B engines. I show some pictures of the new kit installed on my sandrail. - MSD 6A direct fire Ignition for Mazda RX-7 Rotary Engine
Converting a 12A rotary engine over from the stock ignition to a direct fire MSD-6A ignition is another way to increase the performance of your mazda engine. Direct fire eliminates the distributor from the primary ignition. The MSD-6A adds a capacitive discharge for better spark. - Performance
A few closing thoughts about how I felt the performance of the sandrail was changed after the conversion to the rotary engine. - Misc
Misc stuff that doesn't fit anywhere else. It's really just me bragging about using the CNC sherline milling machine to create a billet rotary nameplate.