R/C Tech Forums - View Single Post - Crank Timing vs. Port Timing

03-30-2012 | 08:21 AM

#27

Z'Stein

Tech Adept

Joined: Mar 2012

Posts: 148

Quote:

Originally Posted by Roelof

For the sleeve I use this:
http://www.amazon.com/Pro-Quality-20.../dp/B000MOI9G6

And I must say the Dremel wall tile cutter is also an awesome tool for the sleeve:
http://www.dremel.com/en-us/Accessor...aspx?pid=TR562

For the crankshaft I use simple grinding stones for a Dremel tool.

For raising the ports you can also try to modify an headshim so it will fit over the sleeve. When placed under the upper edge of the sleeve you will raise all the ports. But what you add to raise the sleeve must be taken away from the head to be sure the combustion chamber will stay at the same height.

This is done a lot, for some brands they are even available:
http://www.capricornrc.com/capricorn...d_product=1320

I tried it on an OS 15RX that I've had for a while. I ordered the pro-quality 20 piece diamond bit set, and at low speed, I slightly opened the exhaust port in the corners (up and out) and the same for the intake ports, but not as much or on both sides, just on the side of the port of the direction of the flow. I also fanged, tapered and lightly sanded the roughness out of the sleeve. Further, I cut .5mm off the opening side of the crank and 1mm of the closing side of the crank. I put this motor in one of my on road cars (NTC3) and its quick/fast as hell! A partner of mine with a Traxxas 4-Tech (3.3), that he is so proud of, couldn't wait to race me. That little 15 is all over that 3.3 from start to finish! He wants me to do his motor now, but I don't want to be responsible for messing up his motor. It's amazing what you can learn and do based on shared information within race forums. Thanks!

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