Q: What is a normal temperature range for a Type IV engine?
A: Generally head temps are desirable below 365°F. I like heads to run 265°F-365°F as a norm. 375°F -395°F is getting warm, with 405°F being too hot for any sustained period of time. Oil temps should run 180°F-220°F, as an optimum. 225°F-235°F is warm and 235°F+ is hot and should see some attention.
Q: Where should I mount a Cylinder head temperature sender?
A: Under the spark plug of at least one cylinder! I have just completed testing and found that the stock position for the EFI sensor (found on TIV engines) can be up to 180°F degrees LOW for a cylinder head temp gauge. This was not its purpose from the factory.
Q: Why can my oil temperatures be hot, but the cylinder heads run cool?
A: Gearing and ambient temps play a key role in the oil cooling of the engine. Higher revs make for more friction and the oil must work hard to absorb that heat and then dissipate it. Gearing that does not match a Type IV engines powerband is the #1 cause for overheated oil.
Q: Why do my cylinder heads run hot, but not the oil?
A: Head temperatures are directly related to load. An increased load and decreased RPM result in higher head temps, as the engine is creating heat but it cannot be cooled, due to low fan RPM. Too high of gearing can cause death to head temperatures, especially in high demand applications. The other key factor to engine temps is tuning, an out of tune engine, gets hot fast…Invest in dynamometer tuning, its like gold!
I’ll be adding more….here, feel free to give us a recommendation on the questions you’d like to have answered.