Normal Engine Temperature?

[cmcfaul]

I believe 190 is the optimal temp for engine longevity.

Chris

73 911 E

[a911s]

Great posts by Ed and Grady. Lots of experience there!

Adding a radiator type cooler as suggested to a US '73S (or any 911 without a cooler or just a trombone cooler) is a great idea, especially if you drive in heat or at the track. Comparisons between the 28 tube and the Carrera style radiator type have shown the radiator coolers do a much better job as long as air is being pushed through them. In traffic, a fan will help in this regard - either automatic or with a manual switch. One thing to note is that the MFI fed mag case engines do tend to run cooler than others. My '72S with its stock radiator cooler runs between 180 and 190 normally. Flogged on the track in 90 degree ambient temps might see it reach 225-230 at the end of a session, never higher. The 2.8, 3.2 and 3.6 motors I've had (even with lots of cooling) have generally run hotter.

Normal oil temp gauge readings of 205 is a number often given as ideal for burning off water, but I would try to keep it at 200 or lower for longevity. The point Grady makes about where oil temps are read is important to consider. Readings of 250 or higher are bad news. I shut things down at 240 now at the track.

The link about cooling from evaporated water is another interesting point. A rain shower on a big RS front cooler will lower oil temps about 10 degrees in my experience. Here's Sherwoods cooling solution: http://www.seinesystems.com/MPC-Home.htm

[Flieger]

I am still curious why Mountain Roads' engine temps would be so different with the same engine specs. The only thing I could think of would be some sort of debris blocking cooling fins on an oil cooler or cylinders.

[Chuck Miller]

I am still curious why Mountain Roads' engine temps would be so different with the same engine specs. The only thing I could think of would be some sort of debris blocking cooling fins on an oil cooler or cylinders.

I'm thinking the same Max.....

My '73 2.4S engine always ran relatively cool except on the track in summer...
I added a radiator style ('72) front cooler with late lines ('74-on) and thermostat just for that reason with very good results.

Interesting point...
When I rebuilt the stock 2.4S engine to 2.7RS+ it now attains running temp to slightly higher level (less then 5d on the gauge) quicker than before ... Then when pushed in RPM, will climb progressively... but then when eased off will recover to its normal temp MUCH quicker than the stock 2.4S......

.... for sure no complaints......

[MarkS]

I am still curious why Mountain Roads' engine temps would be so different with the same engine specs. The only thing I could think of would be some sort of debris blocking cooling fins on an oil cooler or cylinders.

Mountains = less air? I think a 28 tube more than adequate on anything under 3 liter. A big + is they are very robust.

[MountainRoads]

I am still curious why Mountain Roads' engine temps would be so different with the same engine specs. The only thing I could think of would be some sort of debris blocking cooling fins on an oil cooler or cylinders.

>> still curious << So is Mountain Roads I noticed almost right away after taking possession again. I knew the PO worked on the carbs and they needed to be adjusted, so thought maybe a bit lean. Local pro took care of that and car ran great, but no change to the warmed-up temp. Reinstalled MFI 6 months later. Also no effect on temp. Even pushed hard in Central Wa. (hot) summer produces +10F max, and siimilar to others, only until I back off. My plan is to give the engine a good Gunk bath as soon as the car comes out of hibernation, removing the oil cooler access port if I can to make sure nothing's hiding in there. Doubt that will make much difference, but I like things squeaky clean, anyway. At this point, I'm wondering if the thermostat might not be fully opening or if the sender and/or guage aren't reporting accurately.

Thanks to all who've chimed in already. Any and all additional thoughts or suggestions welcomed. Just to be clear - stock '71E. No external cooler.


- MR

[merbesfield]

I am still concerned about my cars temp. I got it back from the shop after having one new injector installed, throttle linkage adjusted and everything dialed in. The difference is night and day. Car drives great now, starts on first turn, fast etc. However, I drove it last night, it was a cool night in GA, did not push it hard, and the temp went to 220-225 according to the gauge. This seems high compared to others especially given the climate conditions. Any ideas what I should look at? Thanks

[edmayo]

I am still concerned about my cars temp. I got it back from the shop after having one new injector installed, throttle linkage adjusted and everything dialed in. The difference is night and day. Car drives great now, starts on first turn, fast etc. However, I drove it last night, it was a cool night in GA, did not push it hard, and the temp went to 220-225 according to the gauge. This seems high compared to others especially given the climate conditions. Any ideas what I should look at? Thanks

One of the tests we run just to verify that the gauge is reading correct is to use one of those infra-red guns and aim it right at the temp sensor to see if their in agreement on temperature. If that really is your temperature it is too high for those conditions. remove the cover duct over the cooler and make sure nothing clogging the fins. If that's good next step is to remove the thermostat and test in heated water with a thermometer to verify the opening temp and for full opening.

[boxster03]

180 to 210 normal depending on stop and go and temps and maybe 220 to 230 if you are doing 120mph at 7000 ft in 100 degree heat. make sure you are using 20-50 oil.

[merbesfield]

I need some suggestions. My car is running great now, but the temp climbs to 240 according to the gauge. I did take a read of the temp using an infrared sensor gun and the readings were 225 at the sending unit and other locations and even hotter under the car so the general feeling is that the engine too hot even if the gauge is reading high. It is barely warm here in Atlanta, if it were summer there is no way I could even drive it. I do not want to run it until I figure out the temp issue. Should I replace the thermostat? That is what my mechanic says I should do. What say you guys?