Putting my Mark IV 454 back together, and noticed that the thermostat housing had no thermostat in it. I know I didn't take it out... wtf?

It usually ran 180-ish before I pulled it, but was down a cylinder and a half - #3 had no compression #5 had 40psi, all the rest were about 180psi.

Can you run a motor with no t-stat, and what are the benefits / problems of doing that? Should I put one in... maybe a 160*?

People remove them in a false attempt to cure a over heating problem. You should always use a thermostat. If engines ran better or more efficiently without them, OEM guys wouldn't put them in the first place. IMHO & my .02

You shouldn't really run an engine without a Tstat. There will be a constant flow of coolant through the system and will somewhat defeat the purpose of your radiator. Running without one will not keep the coolant in the radiator long enough for the radiator to dissipate the heat the the coolant has absorbed from the engine block. The thermostat regulates the flow thus regulates the temperature of the coolant. By drilling a couple of small holes in the thermostat, you will get some flow past but still able to regulate most of the flow. :)

u should aways use a stat, start with a 180 and see how it runs.

Ive never used one and drive everyday on the street never had any issues maybe the climate here allows for it? My main reason is I leave the fan & waterpump on at the track between rounds and if I had a T-stat it wouldnt allow flow.

You shouldn't really run an engine without a Tstat. There will be a constant flow of coolant through the system and will somewhat defeat the purpose of your radiator. Running without one will not keep the coolant in the radiator long enough for the radiator to dissipate the heat the the coolant has absorbed from the engine block. The thermostat regulates the flow thus regulates the temperature of the coolant. By drilling a couple of small holes in the thermostat, you will get some flow past but still able to regulate most of the flow. :)


perfect explanation!!!

I've tried with and without and my car did run hotter without one under certain driving conditions. I like to use a high flow thermostat at 180°.

Drilling a couple small holes in the thermostat does nothing for cooling, but helps get the air out of the system that gets trapped behind a closed thermostat when refilling the radiator.

Thanks guys... 180*, maybe with a small hole or two it is.

Maybe I read to many articles on prostock racing or something. I use a 160 or I clip the center out of a old one and use the ring. Most things run 160-180 may be too cool but I push the compression on most stuff so I belive in cool temp and deep gearing. Hot oil / cold intake.

You shouldn't really run an engine without a Tstat. There will be a constant flow of coolant through the system and will somewhat defeat the purpose of your radiator. Running without one will not keep the coolant in the radiator long enough for the radiator to dissipate the heat the the coolant has absorbed from the engine block. The thermostat regulates the flow thus regulates the temperature of the coolant. By drilling a couple of small holes in the thermostat, you will get some flow past but still able to regulate most of the flow. :)

perfect explanation!!!

A radiator is not a water cooler, it is a heat dissipater. Slowing the flow through the radiator will result in increased engine temperatures, as the cool end of the radiator becomes less efficient at dissipating heat. You need only observe the operation of the thermostat to see this principle in operation.
Another function of the thermostat is to introduce turbulence in the flow, which results in better heat transfer.

A radiator is not a water cooler

Sorry, but I missed something here. Where was this mentioned? :cool:

Ive been runnig without a stat for like 3 years now. I have a 160 degree stat sitting on the shelf. I just never got around to putting it in.

You shouldn't really run an engine without a Tstat. There will be a constant flow of coolant through the system and will somewhat defeat the purpose of your radiator. Running without one will not keep the coolant in the radiator long enough for the radiator to dissipate the heat the the coolant has absorbed from the engine block. The thermostat regulates the flow thus regulates the temperature of the coolant. By drilling a couple of small holes in the thermostat, you will get some flow past but still able to regulate most of the flow. :)


A radiator is not a water cooler


Sorry, but I missed something here. Where was this mentioned? :cool:

Contrary to popular belief, the water does not need to spend a certain time in the radiator to dissipate the heat it has absorbed, or reach any particular temperature, as a cooler might do. It does not need to cool by any specific amount, it merely needs to dissipate enough heat to balance the engine heat production. A radiator is most efficient when it is as uniformly hot as you can get it, which means making the outlet as warm as you can. The faster you run the water through the radiator the better it works and the cooler your engine will run. This is how the thermostat works, as the engine gets warmer, it opens up and increases the flow through the radiator. This increased flow raises the temperature of the outlet of the radiator, increasing the efficiency and heat loss.

The deal about drilling holes in a T-Stat's outer ring seat is to allow trapped air to bubble out when you are trying to purge it after doing a flush job!

Of course, roger is right, b/c there is a schosh a water that will get through the holes to help circulation before it opens, but it's much better to purge ALL air outta the system so the holes should be drilled!!

pdq67