CHT guage readings, What should they be? Options

[Jaiden]

I installed my CHT guage and sender (voltage type) yesterday on cylinder 3 and did not get a chance to run the car to temp.
What range should the readings be? I do not have any other temp sensors hooked up on the car yet.

Hopefully I'll get the new sender for the 912 Oil temp guage installed tonight.

I just want to make sure that the car is running within spec so I can start driving her. I did not want to drive the car very much without knowing the state of the engine.

[Mueller]

this is from Jake Raby from another thread:

QUOTE

As for temps... Here are my standards ALL MEASURED UNDER THE PLUG! 275-350 perfect for flat line driving 350-375 OK for climbing the occasional hill or for engines that are driven in 5th gear BELOW 3500 RPM- DO NOT DO THAT IN A TEENER!(people wonder why 2.0 heads crack) 375-400 Very warm- don't sustain these temps for more than a few seconds. 400+ You are aging the heads, startsing cracks and waiting for a dropped seat followed by the opening of your wallet.

I recommend you browse the entire thread for some more infomation that'll be nice to know.

CHT questions and answers and more...

[lapuwali]

My 1.7 with Webers but stock otherwise did these kinds of numbers:

275-325 when tootling around on surface streets
325-375 cruising at 70mph
375-400 climbing a steep grade

Note that CHT figures are very sensitive to engine load, not revs or even ambient temps. HOWEVER, the VDO and Westach gauges are calibrated to read correctly at roughly 70dF ambient temp. If it's hotter than this outside, the gauge will read LOW. If it's colder than this, the gauge will read HIGH. So, the numbers are fairly approximate. On a 100dF day, freeway cruising should show closer to 325. On a 30dF day, freeway cruising should show closer to 375dF, all else the same. On a 70dF day, 350dF is about right.

Oil temps lag CHT by a large margin. After startup, you'll find CHT will hit roughly 300dF within one minute of just idling, where oil temp will remain below 180dF for several minutes. Oil temp seems to be affected more my ambient temps, and they generally go up with revs. Oil temps change fairly slowly, where CHT changes pretty quickly. On the 912 oil temp gauge, the temp is about 180dF when the needle is on the hot end of the lower white box. 220dF is roughly midway between the boxes, and 240dF is the cold end of the upper white box. The red line is about 280dF. I don't have an oil temp gauge in my 914 (yet), but in my 912, it runs about 190dF on cold days, 220dF on hot days.

[Jaiden]

Thanks alot guys!!!

[914forme]

Hopefully less than 1220.58 F or you will have something to write about.

[Jaiden]

Well checked the temp last night and was running around 275-300 so it looks like I'm good to go!!!!

Thanks again for the info!