305 running to cool??

My sbc 305 runs at 160-170 degrees, even in this texas heat, It has a 160 thermostat, I have been told that running to cool is bad for the engine. Should i change the thermostat ?? Thanks ,DUCKMAN

 

Summit published some data that cyl wall wear is 3 times as much @ 160 as @ 180-190, & (I think it sais twice as much @ 170). Can contribute to gunk in the oil too.

 

Yes, change the thermostat to a 185 or 195.

 

Sounds like a terrible problem to have!

 

General Motors installed a 195 degree thermostat in about ALL the 305's from the factory. The NASCAR guys have run DYNO results that show that the engines make more POWER at 200 or so ... over 160/180

 

Don't v8 boat motors usual run down round 160...due to sucking that cool water from the lake/ocean?

 

Maybe some low tension rings can cure that problem.... Go with a 180 degree stat.

 

Use 185 thermostat ... If your timing is retarded it will run a cooler as well.

 

Thanks guys, I have replaced the temp guage and still have the problem so I will replace the thermostat and get it running hotter,Duckman

 

There was almost a 2.5 mpg difference from when I ran at 165 compared to 200-210 in a sbc I had. That particular combo liked heat for some reason.

 

"There was almost a 2.5 mpg difference from when I ran at 165 compared to 200-210 in a sbc I had. That particular combo liked heat for some reason."

They get better mileage at higher temps - that's why late models all run at 200 or more. I don't remember the physics of why, but you definitely get better mileage at higher temps.

 

I have the same problem in both cars I built in Texas, now that I'm in Chicago I can't get them to warm up in the winter.
Good Luck

 

Is 160 a low number for all motors, or just SBC's? My Y-Block Ford has run 160 in hot humid conditions, do I need to think about a different thermostat as well?

 

I don't think theres as much cold water entering those engines as you might think.
I don't KNOW boating but I gave a friend a hand to rebuild one once and i remember it being complicated in the cooling dept.
They used preheat exhaust manifolds and restrictors to keep the water in the preheaters and then the block for a period of time to let the engine reach a proper operating temperature.
It wasn't just a big stream of cold water directly into the cooling jackets.

I THINK most of the car style engines use a closed system now.

 

I suspect wall wear is wall wear, except maybe for nickle content. Some engines have more than others.

 

The real scoop is that optimum running temp for any internal combustion engine (best for engine life and fuel economy) is 180 degrees.

I had (now passed on ) a buddy who was a powertrain engineer for one of the big 3 and this is what he said.

 

The higher temps help keep moisture and other deposits out of the oil, assuming that the crankcase is properly vented. Quicker warm ups mean the choke opens sooner saving some fuel. Some later GM Qjets went so far as to have dual-displacement accelerator pumps that were temperature controlled. As the engine warmed up it required a slightly smaller accelerator pump shot. Advanced ignition timing helps keep the heat of combustion in the cylinder where it can make power. Retarded timing lets more of that heat escape out of the exhaust where it just... well, heats up the exhaust system instead of helping push the pistons.

 

Me and my SBC are both happy at 185F.

 

Most engines i have had seem to run better at 190 or so.My Dodge dragcar runs its best at 195-200 .Believe it or not i will sometimes turn the electric fan off during the burnout to make it heat up to the sweet spot .My motor will run a full tenth faster in the 1/4 at 195-200 on the line vrs. 180-185 ...

 

Click here: HOTRODSRJ’s COOLING TIPS Operating temperature vs power and longevity!