A 521 in Massachusetts

[Crashtd420]

So by design it seems I do have a 180 sensor, and while looking them up i found out it doesn't shut off till 165..  I actually thought they turned on and off at the same temperature...

 

I do i run my sensor above the thermostat in the top cover of the housing.... would it make any sense to change that sensor to open at a hotter temp ?

185 on/ 170 off or maybe

190 on/ 175 off.... 

Or leave it as is.... 

[Crashtd420]

No datsun today... 25 degrees and Icy this morning... supposedly getting 1 to 2 inches of snow tonight..... yesterday may have been the last driving day till spring...

[Stoffregen Motorsports]

17 hours ago, Crashtd420 said:

So by design it seems I do have a 180 sensor, and while looking them up i found out it doesn't shut off till 165..  I actually thought they turned on and off at the same temperature...

 

I do i run my sensor above the thermostat in the top cover of the housing.... would it make any sense to change that sensor to open at a hotter temp ?

185 on/ 170 off or maybe

190 on/ 175 off.... 

Or leave it as is.... 

Yeah, that's one that still confuses me.

 

Thinking out loud here -

The crate GM LS3 motors I install come with a 187 degree t-stat.

The fans come on at 207.

The fans shut off at 197.

 

So that means the fans don't turn on until the motor is well past the t-stat open phase, and theoretically, the t-stat is open the entire time...? No. I can see the coolant cycling at around the same intervals as the fans. The difference here is the t-stat is on one side of the motor, at the h2o pump, while the temp sensor is on the other side of the motor, in the front of the cylinder head. But, the t-stat only STARTS to pen at 187, it probably doesn't reach its full open spot until 200 or so.

 

My understanding is that in an ideal setup, the t-stat and temp sensor/sender needs to be about 10 to 20 degrees hotter than the t-stat. To allow for full open. I need to get a better understanding of the V8 coolant path, but on the Datsun with the t-stat and temp sensor directly adjacent to each other, we should test that theory.

 

As an experiment, you may want to test the t-stat in a pot of water on your stovetop, with a thermometer. Or does the t-stat you bought come with those numbers?

[Stoffregen Motorsports]

Ok, I just did a bit of reading.

 

The "cruising" temp of the motor has the t-stat open, to some degree (no pun) almost the entire time.

A typical 180 degree t-stat opens within 3 degrees of its rated temp, so 177 to 183.

A typical t-stat reaches full open around 15-20 degrees higher than its listed temp, so 180 = 195-200.

The fans should turn on a tad higher than the full open temp, so 205-ish.

 

It seems most experts are setting a 180 degree t-stat to turn the fans on at 205-210 and off at 190-197.

 

That makes sense. I guess I always figured that the t-stat opened and closed during normal driving. I guess I was wrong.

[Crashtd420]

From what you said I think I could get away with changing it.... 

I'm not sure I want it up to 200 or 205 before the fans kick on though.... I know it's fine for a datsun but I think a 190/195 sensor might be the sweet spot for me.... I'd just feel more comfortable with them on sooner but off as the thermostat is closing.....

 

[Crashtd420]

14 minutes ago, Stoffregen Motorsports said:

 

That makes sense. I guess I always figured that the t-stat opened and closed during normal driving. I guess I was wrong.

I guess I thought that too.... 

My fans are wired to stay on after shut down that why I figured having them turn off at 180 would be ideal....

Now I'm think the 195 would be the ideal sensor..... 

[Crashtd420]

26 minutes ago, Stoffregen Motorsports said:

 

As an experiment, you may want to test the t-stat in a pot of water on your stovetop, with a thermometer. Or does the t-stat you bought come with those numbers?

No information on the box, I could look it up and see if anything Is listed....

Unfortunately old one is gone and new one is installed so no experimenting....

[Stoffregen Motorsports]

6 minutes ago, Crashtd420 said:

From what you said I think I could get away with changing it.... 

I'm not sure I want it up to 200 or 205 before the fans kick on though.... I know it's fine for a datsun but I think a 190/195 sensor might be the sweet spot for me.... I'd just feel more comfortable with them on sooner but off as the thermostat is closing.....

 

Oh, right. Every motor has its sweet spot. I wouldn't be afraid to run a Datsun L motor to 200, but I wouldn't want that to be the cruising temp. Maybe 195 cruising temp.

 

2 minutes ago, Crashtd420 said:

No information on the box, I could look it up and see if anything Is listed....

Unfortunately old one is gone and new one is installed so no experimenting....

Maybe get another one to do the stovetop test.

[Crashtd420]

The only thing is saw under specs was when the mentioned the temperature it did list it as:

Starts to open at 180...

[datzenmike]

Begins opening at 180F but stabilizes and runs 185F or so. You want the thermal sensor hotter than the opening temperature or it will be running all the time the engine is warmed up. I have a 189F or 193F, whatever the  later '95 and up Altima with the SR20 used. Car runs half a needle above dead center on the gauge when moving but if idling or slow, fans only come on at 2/3 gauge. Run for 10 seconds shut off for 30.

[Crashtd420]

13 hours ago, datzenmike said:

Begins opening at 180F but stabilizes and runs 185F or so. You want the thermal sensor hotter than the opening temperature or it will be running all the time the engine is warmed up. I have a 189F or 193F, whatever the  later '95 and up Altima with the SR20 used. Car runs half a needle above dead center on the gauge when moving but if idling or slow, fans only come on at 2/3 gauge. Run for 10 seconds shut off for 30.

I'm on the centerline when ever I drive.... the other day was the first time it didn't fluctuate because I fixed the thermostat issue.... 

My guess is that centerline is actually 180, because when it hit the line my indicator light for my fans come on.... so a little over should be fine..... 

I think I'm going to try the 190, because it does run hotter when I use the ac, and those are the hottest days of the year.... 

I'd rather have them on sooner than later.....

I can always try a 195 after that if everything seems ok.... I'd rather go up slowly vs overheating accidentally...

[datzenmike]

I drove a Plymouth Sundance across Canada. When ever I pulled over for gas the fans were not running in fact it would take several minutes of idling to make them come on. Even waiting at lights they rarely came on. Vehicle movement was enough to cool the engine so the turn on temperature had to be well above the thermostat range or it would be running much of the time the engine was running. Kind of negates the use of electric fans on a RWD car, might as well run mechanical. I strive for the fan to be off as much as possible while driving and on only when there is little to no air passing through the radiator.

 

I've seen builds with fans that are turned on by the driver. This is the worst possible way as it allows for human error. The fans have to be automated and basically fool proof.

[Crashtd420]

3 minutes ago, datzenmike said:

I drove a Plymouth Sundance across Canada. When ever I pulled over for gas the fans were not running in fact it would take several minutes of idling to make them come on. Even waiting at lights they rarely came on. Vehicle movement was enough to cool the engine so the turn on temperature had to be well above the thermostat range or it would be running much of the time the engine was running. Kind of negates the use of electric fans on a RWD car, might as well run mechanical. I strive for the fan to be off as much as possible while driving and on only when there is little to no air passing through the radiator.

 

I've seen builds with fans that are turned on by the driver. This is the worst possible way as it allows for human error. The fans have to be automated and basically fool proof.

Sounds like I shouldn't be worried about using the 195 sensor ...

 

I do have my fans on a switch but only as a back up....

I also haven't figured a way to wire them while using the ac.... I currently have to activate my idle up solenoid and fans separately when I turn on my ac.... 

I thought about using the fan clutch trigger but that cycles... would work for the idle up but I think the fans need to be on while the ac is running.... but that's something for another day.....

[Stoffregen Motorsports]

4 hours ago, Crashtd420 said:

I'm on the centerline when ever I drive.... the other day was the first time it didn't fluctuate because I fixed the thermostat issue.... 

My guess is that centerline is actually 180, because when it hit the line my indicator light for my fans come on.... so a little over should be fine..... 

I think I'm going to try the 190, because it does run hotter when I use the ac, and those are the hottest days of the year.... 

I'd rather have them on sooner than later.....

I can always try a 195 after that if everything seems ok.... I'd rather go up slowly vs overheating accidentally...

I wire my fans two ways, depending on the area of the country the vehicle is going to.

 

1 - Fans always on when A/C is turned on. Sometimes I'll wire it so only one fan is on with A/C.

2 - Fans cycle with A/C compressor.

 

If you have room for a pusher fan, you could install one in front of the condensor dedicated to the A/C.

[Crashtd420]

2 minutes ago, Stoffregen Motorsports said:

I wire my fans two ways, depending on the area of the country the vehicle is going to.

 

1 - Fans always on when A/C is turned on. Sometimes I'll wire it so only one fan is on with A/C.

2 - Fans cycle with A/C compressor.

 

If you have room for a pusher fan, you could install one in front of the condensor dedicated to the A/C.

I have looked at the pusher idea but  l lack the room... I was thinking about some smaller motorcycle fans but again haven't pursued that yet....

 

I honestly need to do a bit of a re wire before i even think about wiring up anything else....

[Crashtd420]

It looks like the end of the datsun driving season this year.....

 

 

The nissan will be taking over the daily driver duties for a couple month.... time for winter maintenance and upgrades on the datsun... 

[mainer311]

We didn’t get anything up here. Got lucky. Picking up the Xmas tree on Friday, and that will likely be it.

Edited November 22, 2023 by mainer311

[Crashtd420]

1 hour ago, mainer311 said:

We didn’t get anything up here. Got lucky. Picking up the Xmas tree on Friday, and that will likely be it.

I'm pretty sure they even salted around here already, we had an icy morning last week....

I'm guessing they might salt tonight... everything is wet and it's going to get cold... 

[demo243]

On 11/22/2023 at 2:24 PM, Crashtd420 said:

I'm pretty sure they even salted around here already, we had an icy morning last week....

I'm guessing they might salt tonight... everything is wet and it's going to get cold... 

That needs a dislike!

 

I hope they didn’t around me … was hoping to get a couple more drives in!

[Crashtd420]

2 hours ago, demo243 said:

 

That needs a dislike!

 

I hope they didn’t around me … was hoping to get a couple more drives in!

Luckily it rained after they did ....

Didn't get cold enough last night so no salting happening..... 

[Crashtd420]

Since the roads are currently salt free and it was 40 out today I took the datsun for a small drive to go pick up my son....

The engine temperature had never been more stable.  Usually on the highway it would drop temperature and my fans would shut off.... I'm now realizing that ment my engine temperature was actually low.... now I stay right at the center and almost to much heat in the can, the truck also warmed up quicker.... 

I'm glad I finally got off my ass and changed the thermostat... next will be the fan sensor now that I actually have a better understanding.... 

[Crashtd420]

[mainer311]

Did you drive it today? It's warm out!

[Crashtd420]

28 minutes ago, mainer311 said:

Did you drive it today? It's warm out!

No.... it was 38 and raining when I left for work.... if it wasn't raining I would have.... it's always colder by the time I get to work due to higher elevation, I just dont trust the potential for ice and idiot drivers...

[datzenmike]

Here they spray brine on the roads if bare. It'll sometimes dry and is there if frost tries to form. Rock salt if snow is already down but that rare. It rains a lot so if rain in the forecast no salt.