Rose City Scale Racing - Portland, Oregon

Originally Mike Ellis was going to do a post build and picture guide on the MTX4 kit, but as they say, stuff happens so here's what he had to say:

Well the new kit arrived and is done. Because of the fact that the original brand was dropped and another ordered I have decided to change this article. The drivers that bought the same brand are more than capable of assembling it without my help. For that reason I will touch on a few areas that some drivers may need help in.

One of the problems I have seen with most brands is the suspension arms do not always swing freely. It is advisable to drop the pin into the arm and see if the holes are lined up. If not then I use a drill bit smaller than the hole and pull it back and forth like a file while holding it at the angle needed to align the hole. You never want to enlarge the entire hole, but enlarge the area to allow the pin to drop through on its own. If you find a bulkhead that has a hole on either end, the same process can be used but it is advisable to mount the bulkhead to the chassis before modifying the holes. This applies to floating and entrapped pins only. Some of the pins are secured by a set screw, so pin fit means nothing.

Once all pin fitting is done, assemble it and check that the arm with the link installed falls freely. This is something that should be checked often. Make it part of your routine maintenance.

During the assembly all parts should fit without any binding or forcing. This includes upper radio trays. You don’t want to build in a tweak. Never expect something to free up after you drive it.

Next the shocks. Take your time! It is very important to never scratch a shock shaft. Be careful when you screw the ends on and lube the orings before inserting the shaft. Measure each shock length and be sure they are the same length,.with out the spring installed. When you fill them with oil stroke them until no air bubbles come from under the piston and set it aside for 15 minutes before installing the cap. You will find it is normal for air to get inside the shock after use. That is why I suggest that they be serviced before each race day.

Engine break in is critical. All engine should be taken apart before they are started. Check for burs around the ports. You can find this by moving the piston up and down carefully to feel any catching of the piston and the port. I have found that an Exacto knife will remove the burs enough so the piston doesn’t catch the port. After you are satisfied with the parts, clean everything with a spray type cleaner and re-oil the parts. Reassemble and install the engine.

There are a lot of different ideas as to the correct method for break in. I will explain my method and add that I have never damaged an engine during break in. The setting on the carb are always good enough to start the engine. On 12 motors I install a glow plug in the #5 range. Once it’s started I richen it up so it blabbers if you give it a lot of throttle, but not so much that it stalls. Next I rev the engine up and down without over reving. Never let a new engine idle. Bump the idle up if you need to but don’t let it run at what would be a normal idle speed. As you run it, check the temperature often. Keep it at 180F, and don’t let it get to 200F at all. Keep reving up and down until you have used a tank of fuel and shut it off. Let it cool down for 10 to 15 minute before repeating the process. After 3 tanks have gone through the engine you can begin to lean the mixture down to a better response. I call this making it crisp. Still do not let it get to 200F.

Next will be driving the car. Make it shift to second even though the engine is not leaned all the way out. There is nothing harder on an engine than reving the crap out of it when it’s new. I might add that if the engine likes to stick to the point of needing to be backed off to get it to start, that needs to be repaired first.

If your engine sticks, my method of repair is to remove the head and button and find some screws and plastic spacers (like you use for the shocks) and secure the sleeve into the casing. I use a small amount of wet moly lube on the piston and sleeve. It is a mild abrasive that will free up the wedge a bit. I personally use an electric drill to spin the motor over. Don’t over do it with the moly. It only takes a little bit. Once you have freed up the wedge, take the engine apart and clean it well, re-oil and assemble. If you don’t free up an engine before you run it, it will always be a pain to start up until it’s about worn out. Take the extra time to do it correctly. Saves money too!

I hope some of this helps. If you come up with any questions feel free to contact me for help. I haven’t spent all these years doing this to keep it to myself.

Later,
Mike