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What temp. thermostat is best?

handloader90

handloader90

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Currently piecing an engine together, working my way up to the top end and want to know what would be the best temperature of thermostat to get.

Engine is a 355 SBC, mild cam, street and trail/offroad driven.

4 speed manual, 1 tons, 37's.
 
I've always used what GM has reccomended since 1968--195 degrees..never had a problem, provided the thermostat doesn't stick open or shut...
Those are designed to work with emission controls and computer sensors,using one lower can affect a lot of things,and none of them good,really..

A cold running engine will sludge up the oil faster,get poor gas mileage,and despite the thinking a cooler thermostat will make the engine less likely to overheat,it doesn't always work that way...it will open sooner,but if the engine has other issues with cooling system parts like a radiator thats clogged or missing a lot of fins,etc,the lower temp thermostat wont help..taking one out completely can also make it overheat--water flows too fast through the radiator and cant cool off enough..
 
No computer, everything else working and tuned, 180*. Works well at this altitude, you will rejet when you get here anyway
 
Thermostat governs minimum engine temp, so using a lower temp thermostat serves little purpose. Properly working, it will never help an engine keep from overheating, if that is what you are worried about. If people don't mistakenly use a lower temp to try and control an overheating issue, it can be used to prevent detonation when fueling or timing is incorrect.

If 195* was introduced back in 1968, it was probably due to emissions. It does help in that regard, but most don't really care about that. The hotter you run the engine, the less work the rest of the cooling system has to do, all else being equal. 195* is well within what GM considered safe on the small block, 220* is one of the temp settings GM used to activate electric fans, and they had to warranty the things.
 
I stopped using thermostats, because too many have failed on me. I use restriction washers instead. Morroso makes a coolant restrictor kit, which has 3 size washers in it. I also live in a mild climate, which allows me to get away with coolant restrictor washers.
shopping
 
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Last two fail safe thermostats (BBC & SBC) I've bought failed out of the box. I think it's worth the time to make sure they open in a pot of boiling water before installing them.
 
1-ton said:
I stopped using thermostats, because too many have failed on me. I use restriction washers instead. Morroso makes a coolant restrictor kit, which has 3 size washers in it. I also live in a mild climate, which allows me to get away with coolant restrictor washers.
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I use a gutted thermostat in my BBC but I also run a Electric water pump and fans. I like to cool it down faster after every run I make. Cools out very quick as well......
 
1-ton said:
I stopped using thermostats, because too many have failed on me. I use restriction washers instead. Morroso makes a coolant restrictor kit, which has 3 size washers in it. I also live in a mild climate, which allows me to get away with coolant restrictor washers.
shopping
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Vegas is not considered a mild climate is it. I've been there and it gets hotter than snot and colder than a witches
 
I'm gonna be running the windstorm fans on a switch. I'm gonna turn the switch on as soon as I get in the K5.

Is it better to just run the washers?
 
handloader90 said:
I'm gonna be running the windstorm fans on a switch. I'm gonna turn the switch on as soon as I get in the K5.

Is it better to just run the washers?
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Don't forget lol.

I use a derale brand wiring setup. It runs about 45 bucks and will control the fans through a temp sensor, which is provided. It's about as plug and play as it gets and no thinking is involved once it's up and running.
 
Does it kick both fans on at the same time or does the small one kick on at a certain temp then the second one at a higher temp?
 
handloader90 said:
Does it kick both fans on at the same time or does the small one kick on at a certain temp then the second one at a higher temp?
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Both at the same time. I don't think I could get away with one fan constantly running or any other combo...that's with a small block. I'm sure it could be wired in but I just let the unit do its work. I will say after running it a bit my alternator wasn't happy...Maybe it was on the way out but it dimmed the hell out of the lights when the fan kicked on. The new alternator will fix that.
 
I always stuck w/ the 195* thermos. When I put the cam and Hypertech chip in, Hypertech recommended a 185*. I left the 195 in and it ran lean. Switched to the 185 and it picked right up. Basically, the lower thermo. fools the puter into thinking it's still warming up so it runs a little richer.
 
How did you measure lean?

An ECM usually uses something like 160 to indicate full operating temperature. You don't really see much affect on fueling above that. Usually a lower temp thermostat is used to reduce the chance of detonation so you can run more timing. However, fueling is dependent on the air temperature (i.e. density) and lowering the coolant temp can lower the intake air temps slightly (because the intake manifold and sometimes throttle body have coolant in them).

Usually the stock temp 'stat is best. You shouldn't drop it unless there is a specific reason to. 160's suck for winter driving.
 
I burned up two relays so far with my windstar fans (over about 4 years). It's only because the start up current is enormous. If you go with windstar fans, look for a controller with soft start or find a way to stagger start them. I have upgraded wires and a 140a alternator and start up still dims the lights, unless I'm already cruising. They cool off in a hurry though.
 
handloader90 said:
I'm gonna be running the windstorm fans on a switch. I'm gonna turn the switch on as soon as I get in the K5.

Is it better to just run the washers?
Click to expand...

I'd second the switch idea being less than optimal. More than one here can attest to what happens with electric fans that are forgotten about that were manual control. Build your own fan control setup, or buy one. I'd also consider running each fan on a separate circuit that is on at a different temp so that you do not run your charging system/relays harder than necessary. Unless you want to spend $$ on a switch that can handle 30+ amps (per fan on startup) you are going to need to run something along the lines of a relay anyway. If you are that close to automatic control already, just add the temp switch(es) and be done with it.

IME with LT1 fans, a single fan is more than adequate, but my temps and application are somewhat mild. I've never hit 220* with the single fan as primary. I'd never suggest dual fans as unnecessary, but if you are thinking you need both of them on, all the time, you are probably mistaken.

If your climate and use is such that things like choke are not an issue, then running a washer is probably fine. It's a valid point that the current state of aftermarket thermostats is very poor. Not sure what the failure rate is vs just what we hear about, but you hear of more failures than I would expect if a product is generally decent. Then again, if a thermostat fails on the trail, how hard is it to yank it out? Not very. At least if it's not freezing out lol.
 
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