Originally Posted by
Riketsu
What are you using to measure the temperature?? I have found that temp guns like Duratrax, Ofna usually are 20-30 degs higher than an exergen at the 270 mark.
It does not behave linearly so I wouldn't suggest using that range to correct your reading.
If you are saying that the engine is 270 without a body, usually you can assume it will go up 20-30 degrees with a body on. Like Roelof said, a colder plug will definitely help, and you should check how many head shims you are using and research the net to see what is the stock shims for 20% nitro.
Good point. I was using the Duratrax one but I also have a large laser thermometer I can test it against. The bigger one is just more of a pain to carry but I know that one is pretty accurate. I only have one shim and I replaced it so I am sure that is OK.