A Look Inside an MRC Tuned REDS 521 Sport

This is a REDS 521 Sport that has been in my brothers truggy. The engine was broken in during November and has been occasionally inspected and has had occasional after run maintenance. After around 7-7.5 gallons the engines performance started to go downhill. I knew that it was the rear bearing since the sound of it was pretty noticeable. The balls of the bearings were still smooth and intact, but the race had been worn down enough to where there was a good amount of radial play and, as I already mentioned, were making noise while the engine was running. I have ordered a set of Avid RC bearings. A steel 7x19x6 front bearing and a ceramic 14x25.4x6 rear bearing. This alone should make the engine’s performance better than it was with the steel rear bearing. I looked back at some old videos and realized that the engine never seemed to run at its full potential. The material and build quality is all there but the timing numbers in the crank is where it was lack-luster. That’s when I decided to put a little bit of work into the engine to make it really shine. Hope you enjoy the video. If you have any questions about engine rebuilding, modifying, or painting RC bodies, DM me on insta @MoralesRC_Designs.

[@johndavidson402]

It's me great video! You really helped me with the Dynamite. 21 modifications!

[@gainsrc]

I'm dealing with the same detonation after engine gets over 210f. Also it will not idle unlessI lean it like crazy. This does not happen until it gets to temp. So you are saying .2mm shim helped? Also what plug are you were uou running? Sry if I missed that in the video..

[@moralesrcdesigns3784]

The engine ran great the way it came out of the box, but I had to be pretty spot on with the tune or else it wouldn’t seem to run right. Adding the shim definitely calmed the engine down in terms of erratic the idle and throttle response was. It widened the tuning window a bunch and made it way more forgiving without sacrificing any sort of power. I’m running an O.S. p3 gold plug right now and it hasn’t given me any problems. Keeps the engine responsive and idle consistent without being erratic

[@flaviorodrigues9168]

How does it feel with the new head shim? I was more stable and easy to tune??

[@moralesrcdesigns3784]

Made more power than original from my mods, but the headshim calmed down the power delivery so it’s still drivable. It also tuned a lot easier and the idle was much smoother

[@blow9899]

Hi sir can i used rot0r starter to reds engine

[@moralesrcdesigns3784]

No. You need a specific crankshaft for pull start and rotostart and reds doesn’t have one