Ideal temperture thermostat for SBC?

[curmudgeon]

My new truck has a SBC 383, cam, Edelbrock carb.
No emissions, no sensors.
I would like some input on the correct temp thermostat to run.
I have a flex fan and an aluminum radiator and does not seem to
have a problem with overheating. Keep in mind that I live in Phoenix, Arizona.
I guess I'm trying to decide to use a 180 or 195 degree and what brand?
I am replacing a Motorad Failsafe that fails trying to get the air (steam)
out of the system.
Thanks! Joe

[Matt167]

The old standard was 180*, but most SBC's can be happy with 195* Tstat's. It will run a little cleaner, less carbon on internals and such.. Given you live in AZ, you may consider a 180*, but 200-212* operating temperature is pretty good

[pat mccarthy]

My new truck has a SBC 383, cam, Edelbrock carb.
No emissions, no sensors.
I would like some input on the correct temp thermostat to run.
I have a flex fan and an aluminum radiator and does not seem to
have a problem with overheating. Keep in mind that I live in Phoenix, Arizona.
I guess I'm trying to decide to use a 180 or 195 degree and what brand?
I am replacing a Motorad Failsafe that fails trying to get the air (steam)
out of the system.
Thanks! Joe

you sure you do not have a air lock in the rad ? 180 would be a place to start you may want to look at a robertshaw stat .you will have to work the air out some set up can be hard.make sure the fill point is at the highest part of the cooling system let engine run till the stat opens up can by very messy and watch out not to get burned..... but that is the only way to work air out sometimes

[curmudgeon]

Pat,
I will take alook at the robertshaw stat.
I do think the problem getting the air out of the system is the fill neck in the radiator
is off to one side and probably 3" lower than the crown of the tank as it fits the shape of the deuce grill shell.

[34_40]

Make sure you get a sleeve type and not a poppet style thermostat. A poppet style costs cost five bucks or less, a sleeve type costs 8 to 10 bucks. Sleeve type can outflow a poppet style and will give a uniform / even temperature in the motor. Poppet style is always wide open then closed tight, you can watch it on your temp gauge - always up and down. I think in Summit or Jegs they call the Sleeve type a high performance thermostat. I know Robertshaw makes both types.

[rspears]

If you run the poppet style drill a small hole, around 1/8" in the flange before installing. That little hole will let all of the air in the block bleed out during fill, instead of having to fill it as much as you can, then starting the engine and trying to "catch" it when the T-stat opens to burp air. The little hole makes the process sooooo much easier.

[pat mccarthy]

If you run the poppet style drill a small hole, around 1/8" in the flange before installing. That little hole will let all of the air in the block bleed out during fill, instead of having to fill it as much as you can, then starting the engine and trying to "catch" it when the T-stat opens to burp air. The little hole makes the process sooooo much easier.

i think they have i check valve in the popet ones if not a 3/16 hole or two would not hurt . if he as a big air lock they can be a bitch to get out i had one in the chevy went around and around with the guy at stewart i had just a shim on stat . he kept telling me i had a air lock in the rad ? well he must of been right .at the time i could not see how he was right but he was

[firebird77clone]

I like the idea of the flange hole, sounds like something the factory should make standard

[34_40]

I tried a 1/8" hole in a thermostat once and the car just wouldn't warm up. Barely any heat from the heater!

[pat mccarthy]

I tried a 1/8" hole in a thermostat once and the car just wouldn't warm up. Barely any heat from the heater!

the robetshaw as a check valve?? .but do you need heat in AZ ?

[34_40]

If they are in the mountains of AZ..??..?? then I'll bet they do!

[pat mccarthy]

If they are in the mountains of AZ..??..?? then I'll bet they do!

hell stay in side ?

[curmudgeon]

I've decided to go with a 180 degree Stant Superstat w/a 3/32"
hole in the flange.
On the Stant websight they stated that the thermo would fully open
15 to 20 degrees above temp on thermostat (195 to 200) that,s
partly why I chose a 180.
Thanks guys! Joe

[rspears]

I've decided to go with a 180 degree Stant Superstat w/a 3/32"
hole in the flange.
On the Stant websight they stated that the thermo would fully open
15 to 20 degrees above temp on thermostat (195 to 200) that,s
partly why I chose a 180.
Thanks guys! Joe

Exactly what I'm running, Joe. My dash gauge reads right at 180F, migrating up to maybe 195F in really hot weather going slow in traffic, and my ECU temp input right at the head outlet will be 192F to 203F at the corresponding temps. My electric fan goes to high speed at 210F, and seldom gets there. Haven't had any problems with it warming up fully within about five minutes, even in the winter temps. I think you'll be happy with that approach, but let us know how it does in the AZ sunshine!!

[Don Shillady]

It looks like this thread is wrapped up and Rodger wants me to start a new thread. I have his directions to start a new thread but this is the SBC Forum and I have almost the same question. Just last Thursday I got my engine started after YEARS of messing around. It is a '76 2-bolt 350 bored 0.030 0ver with a nominal rebuild, mild cam, cleaned exhaust ports in 882 heads and heads milled to give 9:! compression ratio. Several years ago I was advised on this site to get a Zip water pump riser and I have searched this site for further information on the Zip Riser but found most information in the Technical section on the H.A.M.B. I admit making several mistakes but my expert help from Progressive Performance (Ashland, Va) and I ran in the cam for about 10 minutes at 2000 rpm but shut it off when the temp. reached 220 F. I know I made at least three mistakes:

1. I used straight Prestone, no water.
2. I had no fan shroud, although a 17" flex fan.
3. I did not purge the air bubble out of the Zip manifold with a 160 F thermostat.

I have spent the last few days adding a shroud (lots of fun!) and I have added a 3/16" hole in the 160 F thermostat. I have also drained the radiator and diluted the Prestone to about 55/45 with water. I also discovered the air bleed on the top of the Zip manifold and I will bleed it after I add the Preston/water back in the radiator and seal it with a dab of RTV. The Zip instructions specify a 160 F thermostat, maybe because the Chevy-6 water pump does not have equal flow rate to the SBC V8 pump it replaced? Anyhow if folks here think 190 F is optimum I will be glad to run at 170 F with the 3/16 hole in the thermostat. If it runs too cold with the hole in the 160 F stat I will be glad to run with a 180 stat also with a 3/16" hole. Just to keep this thread going I will report the results of this setup in a day or two. A complication is that I will have to modify one of the lines to the trans cooler at the bottom of the Walker Cobra radiator since the old line position conflicts with the bulge of the shroud at the bottom and I may have to bend a new line around the bottom of the shroud. Stay tuned, I am amazed that several of you as well as the H.A.M.B. examples run cool but I have made three change/improvements and I hope it will run cool with these changes. I will welcome any and all suggestions as to what I might do more.

Don Shillady
Retired Scientist/Teen Rodder