Reverse rotation 4s for twin
02-14-2015, 04:01 PM
#2
From what I've read, Enya 4C's can be re-timed to run in reverse. I don't exactly know how to set it up, but I've seen it mentioned many times over the years that it can be done. Not sure on OS or Saito.
02-14-2015, 05:23 PM
#3
OS and Saito in the past made reverse rotation camshafts for some of their four stroke engines. But they haven't done so for quite a while now though. As mentioned most Enya four strokes cam be retimed to run in reverse.
But you do not need to run a engine in reverse for twin engine planes. They fly fine with both engines running the same direction. You do not gain anything from reversing the engine. Problems are finding reverse propellers to use, as they have a very limited selection of reverse props. Also the prop nut now has a tendency to come loose on you as it gets loosened when running in reverse. The stronger torque pulses from a four stroke engine magnifies the tendency for the prop nuts to come loose too.
For example:
But you do not need to run a engine in reverse for twin engine planes. They fly fine with both engines running the same direction. You do not gain anything from reversing the engine. Problems are finding reverse propellers to use, as they have a very limited selection of reverse props. Also the prop nut now has a tendency to come loose on you as it gets loosened when running in reverse. The stronger torque pulses from a four stroke engine magnifies the tendency for the prop nuts to come loose too.
For example:
To reverse the rotation of an Enya .53 four stroke engine it is necessary
to move both cams seven teeth away from the timing marks. Proceed as
follows;
1. Remove the glow plug. Set the engine at Top Dead Center on the
compression stroke.
2. Disassemble rocker cover, rocker arm assy. and remove push rods.
3. Remove carburetor and manifold assy.
4. Remove timing cover and push cam followers up out of the way. You should
now see the four timing marks lined up with each other, two on the timing
gear shaft and one on each cam. If they're not next to each other, you are
not on TDC compression. You'll need to carefully rotate the crankshaft one
revolution. Marks should now be together.
5. Remove each cam and set it aside on its respective side. The first cam
that you'll put back in place is the left cam i.e. the intake side. Set it
in place with the timing mark seven teeth offset to the clockwise rotation.
Now replace the exhaust cam with it being offset seven teeth to the
counter-clockwise rotation.
6. Reassemble engine and adjust valve clearance.
7. Go have fun!
These settings are for the .46 and .53 engines only!
The settings for the larger Enya engines are 11 teeth in the same sequence!
If you have problems, you can contact me via e-mail.
Ed Hershon
Southern Maryland, USA
to move both cams seven teeth away from the timing marks. Proceed as
follows;
1. Remove the glow plug. Set the engine at Top Dead Center on the
compression stroke.
2. Disassemble rocker cover, rocker arm assy. and remove push rods.
3. Remove carburetor and manifold assy.
4. Remove timing cover and push cam followers up out of the way. You should
now see the four timing marks lined up with each other, two on the timing
gear shaft and one on each cam. If they're not next to each other, you are
not on TDC compression. You'll need to carefully rotate the crankshaft one
revolution. Marks should now be together.
5. Remove each cam and set it aside on its respective side. The first cam
that you'll put back in place is the left cam i.e. the intake side. Set it
in place with the timing mark seven teeth offset to the clockwise rotation.
Now replace the exhaust cam with it being offset seven teeth to the
counter-clockwise rotation.
6. Reassemble engine and adjust valve clearance.
7. Go have fun!
These settings are for the .46 and .53 engines only!
The settings for the larger Enya engines are 11 teeth in the same sequence!
If you have problems, you can contact me via e-mail.
Ed Hershon
Southern Maryland, USA
Last edited by earlwb; 02-14-2015 at 05:27 PM. Reason: add more info
