I have a 89 Iroc with a new 350hp crate 350. It is carb. I have both fans coming on at the same time and a 160 thermostat. My fans come on about 180 and kick off at 165. Is this good or too low? I have the probe that goes between the fins in the radiator. It seems to work real well.

180-190

I think it depends on the motor, as no two are the same. Most days, even in the dead of summer or the coldest winter day, on the highway my guage is reading about 170. In town it warms up quick and will easily rise to 220. My fans are set to come on at 185 and off at 170 +/-. But my point is the car runs fine at all these temps. But Ive also had Chevy V8's in the past that seemed to run better at other temps, some being warmer (the OEM TBI 305 previously in the car liked to be warmer about 200), while others I've had liked it colder. So I'd say whatever works best for YOUR car.

Run it as hot as you can, 160 is likely too cold. A 180 heavy duty stat or 195 high flow might be what you need.
You want to run what ever temp gives you a stabile temp, if your temp is swinging up and down by 40 or 50 degrees your cooling system will never propery pressureize, if its not pressureizing then you could have surface boiling, that much tempture change could be enough heat cycle the metal, cause stress and possibly cracks or gaskets to let go.
Plus over cooled engines ware out faster.
I would take a hot stabile temp over a cooler bouncing temp any day.

i found an article on optimal cooling temps in one of my
corvette mags,said most of the nascar engine builders
like the engines to run at 220-230*as they feel that
temperature gives the best compromize between lower
cylinder wall friction and preventing hot spots in the
heads.
I use 195* in my cars.

Why is that?Just curious cause I run a 160* stat cause of the summer heat here.Plus it doesnt get too cold here.Both my fans run all the time(on purpose)Runs between 180 and 200 in summer time depending on traffic.Runs 170 or so in winter.I had heard with my alluminum heads and higher compression it was a little better to keep it running cool.But if that temp is good enough for nascar its good enough for me.It sure seems to run better cool.

All I know is that the old guys, racers and the old racer guys really know their stuff, listen to them.
If they have been doing some thing a certain way for 20-30 years it means it works and no one has found a better way.

I do know that motor oil doesn't really start to fully protect and work like it should until its heated to about the boiling point of water. I have herd that for the antiware addtive ZDDP to activate it takes nearly 1000 degrees and high pressure between metal on metal moving parts for the chemical to break down and coat the contacting parts with zinc.
Plus heating your motor oil well above the boiling point of water drives out the moisture, which you know what moisture inside an engine can do. In addition to rusting surfaces it will allow the formation of acids.

I have 113 casting aluminum corvette heads in the machine shop getting resurfaced and stuff, I plan on running them with a 195HD or 195HF thermostat. I expect strong low end power, out standing fuel economy and long engine life with them.

Please reread and explain what temp you meant for zddp to activate.If I read correctly you said 1000 degrees.That must be a mistake.Just saying
.

I run a 195 T-stat but my car runs at 160 degrees all the time... Im not sure whether to trust the gauge or not... but it acts normal. I can see the temp rise to about noon, a little before the 220 mark, and then it drops back down to 160 as the t-stat opens and just hovers there. I can also turn my fan off at idle and watch it climb... but 160 just seems really low. Is it really possible for a car with a 195 thermostat to run at 160 all the time? That the coolant in the cylinder heads is 160 degrees and the coolant at the thermostat is 195?

I am not sure how hot that chemical has to get to function, but think. It has to be stable at over 300'F and activate before the cast Iron parts melt together. So it likely activates some where above a minimum of several hundred degrees F.
Metal parts rubbing together at the contact point can hit 1000 deregrees no problem and Zinc melts around 900 degrees. Under heat and pressure the zinc gets laid down on the contacting parts and the rest of the chemical gets burned off so you know this process is happening at a temp much higher than the bulk of the oil sitting in the pan.


That is not good. Got a thermostat bypass and lots of air flow?

Lately now that it is getting cooler out my car has been warming up slowly and running at about 180 with around 20-30 degrees of needle swing. Thats from using a 195'F high flow thermostat, I need to put the 195 heavy duty thermo back in there. I would like my car to run above 200 to no more than 220, and the less temp swing the better. If I could get the temp up to 220 and never move when warmed up that would be fine with me.
When I put my 6.2L diesel suburban back together was considering digging up 205 degree thermostats.

To me its too hot here most of the time for a 195.I get no temp swing on my known working after market gauge and with a 160 stat in summer it stays right around 190 in heavy traffic.I do go up to a 180 in winter,and it stays about the same.Did it with my 305 and had no isues.Inside of that engine still looked great when I did the swap.I`ll stick with what I`m running.We can have 2 months of 100 degree weather here.I always considered heat an enemy to engines.

on the topic of stable temps...every since I got the air dam back on my FB my temp says rock steady at the middle mark between the 100 and 'noon' as some call it 220...the only time it goes above that is when I sit at very long lights or have prolonged times of not moving ...once the car gets moving again it's no time at all till it goes right back to where it was before the long, non moving times...

I do hear the fan kicking on about the time the gauge hits 'noon' and it seems to kick off about 20 or so degrees cooler...

seemed to me like the air dam and thermostat was working just as they should...?

am I incorrect here?

thought about changing stat to raise temp a bit but not sure...

seems to run good the way it's operating but I can't say if it's at peak efficiency right now or not...

any ideas?


thanks

Zeke

Over all your temp sounds good, just need to stabilize it a little bit more.
Try installing a fan switch that kicks the fan on at a slightly lower temp, install a manual switch, or install an additional pusher fan that you can turn on when ever you need it.

I appreciate those suggestions...

can you tell me where the fan switch is located and are there many different temp settings that they come in?....price?

thanks a lot

Zeke

Fan switches are pretty cheap, just make sure you dont accidently get a sensor for an ecu or a temp gauge.
Summit racing is the first place that I can think of.

>>>



thanks...I look at summit's stuff once in a while...where abouts on the car is that switch located anyway?


appreciate it

Zeke

Does anyone have the part numbers for the fan switch and temp gauge sender? Are they the same?

If you want to talk old school tuning, they throw away pretty much every single sensor and tune for exhaust gas temp. Nothing else matters according to some of race engine builders I talked to.