BLACK Z

HI, i have a 350, three core radiator single elec fan, new gm water pump, I have a jet 180 fan switch, and the lower air dam installed, I am just wondering what thermostat you guys are running, i am not running the computer any more, Holley carb MSD Dist.

Also do you guys drill holes in your thermostat.

Do you guys like one brand better then the other, I remember years ago i had one that seemed to be bigger and flow more then others, don't remember the brand.

hdis2002

iTrader: (1)

180 Thermostat, 195 fan switch. No particular brand. L98 engine.

joshc

iTrader: (1)

If you have a 180 fan switch you want a 160 thermostat.
I personally run a 180 thermostat fan switch that turns on at 195 and back off at 185

I like the Stant Superstats. Made in USA, stainless steel construction and they flow pretty well when open.

plum92_camaro

160º stat, 176-166 hypertech fan switch. Everything else in the cooling system is stock. On super hot days (100+ and humid) it will get up around 180-200 but really that's still reasonable operating temp.

TTOP350

iTrader: (8)

Stock rad, no A/C, aluminum heads, edelbrock waterpump, 160º stat, 176-166 hypertech fan switch.

Temp gauge hardly moves off of 160

StevenB L98/LS1

91 L98 TPI edelbrock high flow intake/runners running stock fan switch with a 180 degree thermostat. the car runs at 180 or below always. I live in florida with high humidity during summer. Car never over heats

BLACK Z

I may order a 160 again, Do you guys drill holes in them or leave them alone?

TTOP350

iTrader: (8)

I drill them all with 2 holes.

Fast355

iTrader: (2)

I drill 1x 1/16" hole in mine just to vent the air.

I would use a GM 170°F. In my 350 powered Express I have a 170°F thermostat, a mechanical clutch fan and use my 0411 ls1 pcm to turn the auxiliary pusher on at 200°F or with the A/C. Heat soaked with the a/c blasting in 105°F weather I stabilize out about 205°F at idle but run about 185°F on the open road.

watajob

iTrader: (29)

170 'stat w/2, .125 holes, manual fan switch, ECM set 185/175. Oh! And a 2 core cheap Chinese rad that seems to function pretty well. Also have an oil cooler, a tranny cooler and a P/S cooler.

topradman

The only need to drill holes is if you are shutting off the thermostat bypass in your water pump. This was a Smokey Yunik trick to block off the "5th hole" in your water pump stopping coolant from making a loop in the front of the engine however, you then had to make provision for pressure relief if you we're still going to run a thermostat or the stat would not open or at least struggle to open. Drilling "4 - 1/8" holes in the flange of the stat provided the new bypass and you then had a system that all coolant movement had to go through the radiator before returning to the engine. This has the most dramatic cooling effect on low slung engines in street rods where coolant had to be pushed up to the top of the radiator as much as 12" high, however, there is still an cooling advantage to doing this in our cars. Drilling the stat if not shutting off the bypass port in the pump is probably a waste of time and of no significant advantage ( other than it will take your car longer to warm up but will not net any cooling advantage overall ).
If you run a 180 fan switch you will need to run the 160 stat or your fan will run most all of the time.

TTOP350

iTrader: (8)

The reason to still drill the hole is so air can't get trapped and not let the T-stat open at the correct water temp.

topradman

[quote=TTOP350;5613151]The reason to still drill the hole is so air can't get trapped and not let the T-stat open at the correct water temp.]
GM didn't feel that was necessary on this application, I don't either. Fill up cooling systems 5 days a week here.

TTOP350

iTrader: (8)

GM also didn't feel it was necessary to install subframe connectors either but people do it 5 days a week to make the car better. Same thing with the holes.
I've done it on SBCs and esp ford 302/351 Windsors for 30 plus years myself. It makes both motors burp that air bubble easier after a R&R.
Will the car fly apart if you don't drill holes? Of course not, does it help a lil bit, yes it does.

BLACK Z

Thinking about this one, looks like it'll flow decent.

KaI_S

180* thermostat, Dual last water pump, stock dual fans, stock radiator
fan on 223* stock ( i believe), stock temp gauge
normal in city 1/2-5/8 temp gauge Highway (45-55 mph) 1/4-3/8 temp gauge

BLACK Z

I Got the one above, it comes with a tiny vent already in the stat so no need to drill, I Put it in and ran the car in garage but have not road tested it yet. I was not having overheating problems before just wanted to knock the temp down a bit and figured Id match it to the fan switch.

novaderrik

195 t stat, fan switch that comes on at 220 and shuts off at 215.. it was built with gas mileage in mind, but it does not detonate at all no matter how hard i try...

regarding the bypass: if you have the heater core hooked up, that's all the bypass you need... drilling holes in the thermostat is a relic from the days of 3/4 race cams and double hump heads on the 12:1 327 in your 65 Impala back in the late 60's...

BLACK Z

When I had the old 195 Stat and stock fan switch it would get pretty close to 220 often, I then added the air dam back below the rad and that helped a lot, I ran 160 Thermostats for a while and added the 180 Fan switch, my car for the most part stays pretty cool, well below the 220, I did a 180 fan switch and stat at the same time, Fan was coming on a lot, now I know why, I have the 160 Stat in there now and all seems well.

TTOP350

iTrader: (8)

Your missing the point of the holes. Its not to provide a coolant bypass, its used as a air bypass when the stat is closed.
Air gets stuck up there in the Tstat area during a r&r and even from steam forming hot spots in the heads during normal low rpm driving, not down low in the bypass. When you run the motor hard, it pushes those air pockets thru and will stop and build up at the stat if its closed.
Your just keeping the T-stat free of air and "stabilizing" the temp operation of it.
The coolant area of old SBC/SBF/BBC heads has high and low spots in the roof areas allowing hotspots and steam to form, that air needs a place to go when the stat is closed.
The LS motor engineers have added a nice flat roof in the heads coolant area and steam tubes on each end of the heads to help prevent hot spots/air in the coolant.

novaderrik

GM built MILLIONS of small blocks, and didn't put a drilled thermostat in any of them... it's simply not necessary. but drill your holes if it makes you feel better.

TTOP350

iTrader: (8)

Completely agree but it does help.

As I said before, GM didn't install subframe connectors on these cars either. They aren't necessary but they do help.

The aftermarket and hot rodders have always tried to make what GM does better.

BLACK Z

Like I said above I have always drilled holes in mine also and the MR.Gasket Hi FLow unit I just installed has a tiny vent type slit in the Stat, which does the same as drilling a hole.

abray1

A 170 is suggested by Myron Cottrel of TPIS and other engine builders. I use one and love it. I also like to drill one small hole to get all the air out of the system. An aluminum rad with two rows of 1 inch tubes seems to work best and after 20 years of trying different fans the Taurus fan blows all of them away.

TFS355S10

iTrader: (2)

Anybody have the part # for the 170 thermostat? I used to have it but can't seem to find it. Pretty sure it's a GM only part?

Fast355

iTrader: (2)

LT1/LS1 dual fans and Nissan Altima dual fans blow the Ford fan away too.

BLACK Z

You guys use different fans on your car's? What model and years and what all do you need to do the swap?

Reid Fleming

iTrader: (2)

I used to run a 160° stat, but switched to a 180° stat about 10 years ago. I prefer the 180 for use in both summer and winter. The extra boost in temperature seems to help in bringing the oil pressure down from full pressure to about 80% of the gauge. It's going to be a minor boost in fuel economy. Especially during the winter months. And I actually have usable heat.

During summertime hell, the stat is going to be open after driving 4 blocks from a cold start and will stay open until I shut the car off. So I'm not going to gain anything from a 160° stat. It seems so backwards psychologically, that living in Arizona, Texas, Florida, etc that the 160° thermostat gives zero cooling improvement during summertime when you need the most cooling possible.....Regardless, sitting on the stat at 180° during the rest of the year is fine with me.

I understand the idea of drilling the thermostat if you've plugged the water pump bypass. But I don't see the point if you're drilling it just for drilling sake. As soon as the stat opens, it's going to let any air pockets out anyways.

TFS355S10

iTrader: (2)

Drilling the thermostat is for when you have drained and refilled the system for whatever reason. It will help prevent an air pocket from forming so coolant will actually contact the thermostat so it will open when it's supposed to. (hot air will more than likely not activate the thermostat)
Small block chevys very seldom have air pocket problems anyway, but drilling a hole won't hurt anything. Pontiac engines on the other hand seem to love airpockets...... LOL