RC Car - My Engine Is Too Hot!

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My Engine Is Too Hot!

Comments: The only problem I am having is the engine temperature. I tried hundreds of set ups and I cannot (never have been able to) succeed in keeping the temperature below 250°F. The needles (high and low end mixture) are as opened as possible (sometimes even too much!!!). Every so often I get readings of over 300°F. Can the OS .21 RZ-B engine support these temperatures? What can I do to decrease them? What would be the highest temperature allowed? I have a friend with the same engine and he has the same problems. Can we make any adjustments inside the engine? Could it be that the needles are too opened?

Thank you in advance.

Response: It sounds like you have an air leak somewhere in your fuel system or engine. If you are running your needle valves at excessively rich settings and still have 300+ temperatures there must be extra air in the engine some how.

Check everything. Replace all of the fuel lines, inspect the tank for leaks, make sure all screws are tight on the engine components. Replace gaskets if necessary. You can even use a high temperature silicone between the backplate and engine and carb and crankcase to reduce air leaks (I do this to all of my engines, even brand new ones). Do not put silicone between the cylinder head and sleeve / crankcase (it may squeeze into the sleeve).

Also check that your pressure line is not plugged at all. If your pressure line is plugged the pressure will be reduced and less fuel will get to the engine (thus a leaner setting).

The RZB should definitely not be running at 300+ degree temperatures. 250 degrees Fahrenheit is the hottest it should get unless you are at a big race or you have a lot of money to replace your engine on a regular basis. For the most part you should try to keep it under 250 degrees.

One more note. You mentioned that you were using a Raytek temp probe (in a previous e-mail). I used to use one until I had an accuracy problem. I was racing in Detroit and I could not get my engine temp below 270 degrees. I tried everything, finally I asked Kris Moore for help and he brought out his Paris temp probe. My engine was running at a temperature of 230 degrees, not 270. I trashed the Raytek ever since. I am not saying that the problem is with your probe, just keep it in mind.

If you can, borrow someone else's probe to see if you get the same (or similar) numbers. I feel even more strongly about this one because your friend is having a similar problem as you.

Let's take off a few tenths per lap,

"PRO"
Pro Racer Secrets