What temp stat to use in High Compression engine?

AngleT

AngleT

Always more tuning to do
Putting my engine together after my BVH compression ring was shaved off and a PBS B3 cam installed by Matt at Midwest-Bayless. I'm also running 9.2:1 compression pistons, Dual 40's, and high output MSD ignition and coil.

What thermostat should I be running with this type of engine so it runs at the proper temperature?
 
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I've used both 160 and 170 with success. Either would normally have my temp settle around 170-175 in normal operation. Mind you that was with a vented cover and Scirroco rad. Only in traffic would it creep to 195-210 or so if left unchecked.
 
stock t-stat

Tom,

With the 1500 twin DCNF, CR 10:1, I use the stock T-stat. It was over 90 today and my trip home was pretty solid at 190 deg F. (even when I got off the freeway). I think I've got a good water pump in this one.

JimV
 
By "left unchecked" do you mean

that without the radiator fans coming on? I've got my engine lid backing removed/"vented" and the side scoops opened up so there is only the vertical lines. I also plan on having my stock radiator flushed before I put new coolant in it. Does removing the side scoop "tubes" from the engine compartment help or hurt cooling?
 
THIS IS MY OPINION

AND ONLY AN OPINION:

On a fresh engine, one that is going through lots of break-in, and generating lots of HEAT because of excess friction, I always take an old thermostat and cut out the valve. I still install the outer ring part, which actually determines the ultimate operating temperature of the engine.

But without the valve, it will take a long time to get up to temp. Which is fine with me because there is lots of wear going on in a fresh engine that needs to be controlled.

Once the engine has been run a few times and I know it's functioning and broken in completely, then I install a new thermostat and gasket. And I also change the oil too, which is usually straight 30 weight for break in. But anyway...I play it safe.
 
Tom:
I had wired in a manual switch for the fan, just to see how hot it would run, and it would only rarely get above 205 in the few instance that I was stuck in traffic. This was according to my mechanical temp gauage tapped to the head. I ended up ditching the fan soon after as I rarely drove the car to work and only at slaloms and weekends.

I don't think the tubes made much of a difference cause once you vent the engine cover, there's more airflow from below through the engine bay that the side scoops become redundant.
 
Hey Tom... yur on the right path...

... IMHO...

Removing the grid work from the side vents allows about 30% more air to pass through...

Removing the raintray allows the heat to vent straight up, especially while in traffic, and evacuate heat from the bay quite easily... so much so... I have taken the LEFT vent and using a 2 1/2" x 3' heater duct... sawed off the stock air cleaner snorkel and connected the two for a FRESH air, as well as a bit of a RAM air intake. Simple, effective, inexpensive, appears stock, works exceptionally well.

As for the remainder of the cooling issues... I too flushed and "rodded" my own radiator using pool acid and replaced the stat and cap... using Stant products, 13 pound cap (18229 or 28229) and a dual action 180 degree stat (45378). My engine runs at 185 degrees all the time while MOVING and the fans ONLY come on during summer months in LA traffic, cycling between about 210 and 185 degrees... and I mean CYCLE, as in on and off.

I also connected an override switch which I use in WINTER months just to exercise the fans... and I said fans, 'cause I have two, one that I installed off another Fiat and wired in PARALLEL with the first fan... with NO upgrade in fusing. Works just fine... for over 10 years now...

Note I also live in the high desert... but I am told I live a CHARMED LIFE... Hopefully your life will soon be charmed also... Good luck.
 
The stock thermostat is the best choice. Its not about keeping the engine from reaching temperature, its about getting to the correct temperature and keeping it in the appropriate range without wide variation.

Running an engine outside of the correct range is not a good thing, the cooling system needs to shed the same amount of heat regardless of what temperature you allow it to reach. A 'cold' engine won't bring the oil to temperature very quickly and can keep more water and light hydrocarbons in suspension longer, neither of which are lubricants.

Nearly all engines use a thermostat which brings the engine up to 190° temp to promote proper combustion. The cooling system is more than adequately sized for the heat generated by the power possible from the engine, all the more so if you put in a Scirocco radiator.
 
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