The picture in the first mail is my TDC finder. All published timing is in some number of degrees from a familiar point in the circle. So you see these locations as TDC, (Top Dead Center) BBDC (Before Bottom Dead Center) and so on. So, any timing reference will be inside of 90 degrees from some known location.

 

This helps you see it in your mind, some distance from one of the 4 locations. So, to start out you must locate TDC (Top Dead Center) with great precision.

 

In the picture you see a front iron with a stationary gear installed. A crank is sitting in the gear. An aluminum angle is touching the throw (eccentric) of the crank. The aluminum piece is pivoting on a piece of case bolt at the far end, and is exactly parallel with the centerline of the iron. The throw then moves the aluminum to the right as it passes over TDC. The dial indicator records this as a null in movement. Since the indicator is as far from the throw as is the pivot, the indicator is seeing double the movement of the throw. So accuracy well inside of one degree is easy to resolve.

 

Once the crank is sitting in the TDC position, a very large degree wheel is mounted to the threaded end of the crank. I cut open a flywheel nut and crimped it closed a bit. I drilled and tapped a 10-32 hole and installed a screw on one side of the cut. Tighten the screw to open the crimped nut and release the crank. Loosen the screw to clamp the nut to the crank. The degree wheel is affixed to the nut with 2 10-32 screws.

 

Attach a long pointer to one of the intake manifold studs. Turn the degree wheel to get the TDC mark right at the tip of the pointer. I used a length of 3/4 steel strap from the hardware store. Now you should have the crank at TDC. And the pointer sitting right at the TDC mark on the degree wheel. Lock the degree wheel to the crank. Tighten down the nut holding the pointer. Check to see that the relationship has not changed. Remove the crank and degree wheel without moving the degree wheel relative to the crank. Lay a clean rotor on the iron in the TDC position. Install the crank through the rotor.

 

Now for the intake timing stuff just go ahead and turn the crank in the running direction until part of the intake port is just exposed. (Intake open point) Record the degree wheel reading. Keep turning the crank until the intake port is just completely covered.(intake closing point). Record the degree wheel reading.

 

For Renesis engines do the exhaust the same way.

 

For others, add a rotor housing and 2 dowel pins. Install a set of springs and apex seals with the corner pieces super glued in place. Record the events as above.

 

Now you have some data to compare to other published data and determine what kind of performance you are likely to have from this engine. You can use this data to mark the rear iron to duplicate the port in the front iron. In engines where the primary ports (in the center iron) resemble the secondaries (end irons) you can make a pattern to move the data to those irons or add the pieces, to your mocked up engine and redo the setup for the center iron. Or with the pointer at TDC and with out moving the crank at all, loosen the big nut and turn only the degree wheel to the 180 mark and lock it down. For marking ports in the number 2 housing. Or if you have a mind like my wife adjust the degrees in your head.   

 

Note that the 6 port has the latest closing ports of all rotaries. If you will have both sets of the secondaries open together perhaps moving the closing line of the upper port would be less than helpful. 

 

Early intake closing (stock port) helps starting, maintains the low speed torque, and makes for a responsive engine from just off idle to 4,000 to 5,000 RPM. Late intake closing points moves the power well up the RPM band and takes it away from the low RPM band. Starting becomes more difficult as less mixture is trapped at cranking speed and sluggish starting becomes the norm.

 

Exhaust porting is another whole book. I would just radius the bottom of the stock port. Make it a bit wider. And radius the top of the port. It is good to start with not much at all is required. Staying near the stock exhaust timing will allow for a dreadfully restrictive  exhaust system. Just like the stock one. With matched headers and a free flowing system, lots of extra power is available along with the noise, if you want to go bigger later.

 

You may want best power (depending on your reduction ratio) to be 5,000 RPM, 5,500 RPM or 6,000 RPM.

 My thinking is that if you cruise just below best power, you have some in hand if you need it. But where you want the peak should be thought out ahead of time.

 

The two TDC locations are when any 2 corner seals align in the vertical.  The 2 BTC locations are when any 2 corner seals align in the horizontal. Easy..............

 

 

Lynn E. Hanover