Correct thermostat 327 motor please?
05-29-2007, 09:06 PM
#1
Le Mans Master
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Correct thermostat 327 motor please?
I have a 350/350 CE motor in my 65. I have a Dewitts aluminum radiator, new fan and fan clutch. The car runs at a pretty constant temp of 200 to 210. I checked it with my IR gun at the thermostat housing and intake water jackets. All say same thing, 200 to 212. Top of radiator 190, bottom 150. I am thinking all is working but possible a faulty or high temp thermostat or maybe an old thermostat that does not fully open? What thermostat should I use? 160 or 180? I live in hot weather so I was thinking a 160 high flow aftermarket? Also, I am not familiar with expansion tanks and how to drain radiator and re-fill and tricks for burping so you don't get air trapped in the motor when draining to replace the thermostat. Easy way to do this? Yes, I see the pit-**** at the bottom of the radiator for draining. But how about filling? Burping? 
Thanks
Thanks
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05-29-2007, 09:27 PM
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I have a 350/350 CE motor in my 65. I have a Dewitts aluminum radiator, new fan and fan clutch. The car runs at a pretty constant temp of 200 to 210. I checked it with my IR gun at the thermostat housing and intake water jackets. All say same thing, 200 to 212. Top of radiator 190, bottom 150. I am thinking all is working but possible a faulty or high temp thermostat or maybe an old thermostat that does not fully open? What thermostat should I use? 160 or 180? I live in hot weather so I was thinking a 160 high flow aftermarket? Also, I am not familiar with expansion tanks and how to drain radiator and re-fill and tricks for burping so you don't get air trapped in the motor when draining to replace the thermostat. Easy way to do this? Yes, I see the pit-**** at the bottom of the radiator for draining. But how about filling? Burping?
Thanks
Thanks
If the temp indicated on the guage and the IR gun is accurate and too high for you or too high for what the car should do then you need to look at increased capacity to dissipate heat once the stat is open. High flow stats might help a tiny amount as opposed to a standard stat but the long and short of it is if it is running to hot (and the stat is working correctly regardless of the temp it opens at) then there are issues in the cooling system.
There are endless discussions on the Forum about faulty readings on the stock guages. Look there you may get some ideas.
Last edited by hpexpatriot; 05-29-2007 at 09:29 PM.
05-29-2007, 09:28 PM
#6
Le Mans Master
Ken
The 160º is not recommended as 160º is too low of an operating temp although the t-stat itself won't dictate the actual operating temp, only the minimum temp.
Usually the 180º t-stat is the recommend choice and get a good one. The Robert Shaw #330-180 is a good unit and is considered a safe one because if it fails it fails in the open position and still allows coolant to flow. It's also marketed under the Mr. Gasket brand name with part # 4364.
to drain, the coolant, simply open the drain valve at the bottom of the radiator. I also open up the cap on the expansion tank to help it drain a bit better. If you want to go the extra step you can also open up the freeze plugs to get more remaining coolant out.
To refill, I than open up the t-stat housing and fill as much as possible in through the t-stat opening, than put in the new t-stat and close that up and add the remaining coolant as needed in thru the expansion tank. I start the car at that point, wait for it to warm up enough for the t-stat to open up and with the coolant now flowing thru the system check the level in the expansion tank and add any remaining amount needed for the proper level and you are done.
I'm not sure if it's really necessary to do this but it was also recommended to me by a few people to turn ON the heater as this will allow the coolant to flow thru the heater box to aviod air pockets and make sure the coolant level is enough to handle that extra bit of system capacity (or so I was told).
The 160º is not recommended as 160º is too low of an operating temp although the t-stat itself won't dictate the actual operating temp, only the minimum temp.
Usually the 180º t-stat is the recommend choice and get a good one. The Robert Shaw #330-180 is a good unit and is considered a safe one because if it fails it fails in the open position and still allows coolant to flow. It's also marketed under the Mr. Gasket brand name with part # 4364.
to drain, the coolant, simply open the drain valve at the bottom of the radiator. I also open up the cap on the expansion tank to help it drain a bit better. If you want to go the extra step you can also open up the freeze plugs to get more remaining coolant out.
To refill, I than open up the t-stat housing and fill as much as possible in through the t-stat opening, than put in the new t-stat and close that up and add the remaining coolant as needed in thru the expansion tank. I start the car at that point, wait for it to warm up enough for the t-stat to open up and with the coolant now flowing thru the system check the level in the expansion tank and add any remaining amount needed for the proper level and you are done.
I'm not sure if it's really necessary to do this but it was also recommended to me by a few people to turn ON the heater as this will allow the coolant to flow thru the heater box to aviod air pockets and make sure the coolant level is enough to handle that extra bit of system capacity (or so I was told).
05-29-2007, 09:35 PM
#7
Safety Car
05-29-2007, 09:48 PM
#8
Le Mans Master
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Ken
The 160º is not recommended as 160º is too low of an operating temp although the t-stat itself won't dictate the actual operating temp, only the minimum temp.
Usually the 180º t-stat is the recommend choice and get a good one. The Robert Shaw #330-180 is a good unit and is considered a safe one because if it fails it fails in the open position and still allows coolant to flow. It's also marketed under the Mr. Gasket brand name with part # 4364.
to drain, the coolant, simply open the drain valve at the bottom of the radiator. I also open up the cap on the expansion tank to help it drain a bit better. If you want to go the extra step you can also open up the freeze plugs to get more remaining coolant out.
To refill, I than open up the t-stat housing and fill as much as possible in through the t-stat opening, than put in the new t-stat and close that up and add the remaining coolant as needed in thru the expansion tank. I start the car at that point, wait for it to warm up enough for the t-stat to open up and with the coolant now flowing thru the system check the level in the expansion tank and add any remaining amount needed for the proper level and you are done.
I'm not sure if it's really necessary to do this but it was also recommended to me by a few people to turn ON the heater as this will allow the coolant to flow thru the heater box to aviod air pockets and make sure the coolant level is enough to handle that extra bit of system capacity (or so I was told).
The 160º is not recommended as 160º is too low of an operating temp although the t-stat itself won't dictate the actual operating temp, only the minimum temp.
Usually the 180º t-stat is the recommend choice and get a good one. The Robert Shaw #330-180 is a good unit and is considered a safe one because if it fails it fails in the open position and still allows coolant to flow. It's also marketed under the Mr. Gasket brand name with part # 4364.
to drain, the coolant, simply open the drain valve at the bottom of the radiator. I also open up the cap on the expansion tank to help it drain a bit better. If you want to go the extra step you can also open up the freeze plugs to get more remaining coolant out.
To refill, I than open up the t-stat housing and fill as much as possible in through the t-stat opening, than put in the new t-stat and close that up and add the remaining coolant as needed in thru the expansion tank. I start the car at that point, wait for it to warm up enough for the t-stat to open up and with the coolant now flowing thru the system check the level in the expansion tank and add any remaining amount needed for the proper level and you are done.
I'm not sure if it's really necessary to do this but it was also recommended to me by a few people to turn ON the heater as this will allow the coolant to flow thru the heater box to aviod air pockets and make sure the coolant level is enough to handle that extra bit of system capacity (or so I was told).
This is good stuff. Thanks! I have always done the filling through the thermostat housing for engine but I also am not use to a radiator without a radiator cap. To me, the expansion tank looks lower than the top of the radiator so I would also think Glenn has a good solution by having the front nose down, rear end up to help fill the radiator? So thanks Glenn also! I ran a high flow 180 in my hotrod and it never went over 195 in 100* temps so I will do another 180 high flow. Thanks all for your valued recommendations. I am still learning about these cars and have a long way to go!
05-30-2007, 07:41 AM
#9
Race Director
high fliow?....
this is either a misprint or a intentional commercial sales gimmick appealing to someone with a bad cooling system. over the years we have sold every make of thermostat that existed. including Gates, Stant, Robertshaw and a few more. The only difference that was ever apparent is that a few special stats had a wobble valve for ease of filling. A side of this feature they all opened the same regardless of it`s commercial hype and or cost.
05-30-2007, 07:50 AM
#10
Team Owner
I suspect your crate engine came with a 195* t-stat for modern emissions reasons. When I drove a 1979 that was the temp recommended and in fact the only one listed in the GM parts book. The operating temps you have noted are in line with my experience with that car and are considered normal. Going to a 180* won't hurt, however.
Last edited by Paul L; 05-30-2007 at 08:54 AM.
05-30-2007, 07:59 AM
#11
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You don't need to go through all those monkey motions just to change a thermostat. Drain it down to where the coolant doesn't come out the thermostat housing when you loosen it. Change the thermostat and button it up. Top off the coolant level with the cap loose. Fire it up and let it run long enough to get the thermostat housing to hot to hold your hand on. Let it run another couple minutes. Check coolant level and top off if required and drive off.
I would use any 180 degree name brand standard flow thermostat listed in the previous post. Always have.
The only time you need to open the heat control valve is if you have a system that has a system that cuts off the coolant flow through the core when the heater is off. A non air C-2 is not this way.
I would use any 180 degree name brand standard flow thermostat listed in the previous post. Always have.
The only time you need to open the heat control valve is if you have a system that has a system that cuts off the coolant flow through the core when the heater is off. A non air C-2 is not this way.
05-30-2007, 10:51 AM
#12
Le Mans Master
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this is either a misprint or a intentional commercial sales gimmick appealing to someone with a bad cooling system. over the years we have sold every make of thermostat that existed. including Gates, Stant, Robertshaw and a few more. The only difference that was ever apparent is that a few special stats had a wobble valve for ease of filling. A side of this feature they all opened the same regardless of it`s commercial hype and or cost.
These high performance thermostats are designed to resist large variations in coolant pressures that occur at high RPM's where coolant temperature and coolant pressure fight for control of the thermostat keeping it from opening at it's designated temperature. The balanced HP Thermostat features all brass and copper construction, and opens at the right temperature regardless of engine RPM.
Summit catalog:
Cooler is better.
High-flow thermostats from Milodon greatly aid the correct functioning of a high-performance cooling system. They're engineered to warm the engine to a proper operating temperature without making it run hot enough to lose power. Also, the "Balanced Sleeve" design equalizes the pressures exerted on the thermostat. This counters the undesired effect of increased flow from a high-volume water pump, which actually tends to hold a stat closed.
Article:
Thermostats & Restrictors
We strongly recommend NEVER using a restrictor: they decrease coolant flow and ultimately inhibit cooling.
For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/ Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.
Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.
A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.
Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.
Seems that there are High Flow which are not the same as typical?
05-30-2007, 08:25 PM
#13
Le Mans Master
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I suspect your crate engine came with a 195* t-stat for modern emissions reasons. When I drove a 1979 that was the temp recommended and in fact the only one listed in the GM parts book. The operating temps you have noted are in line with my experience with that car and are considered normal. Going to a 180* won't hurt, however.
05-31-2007, 12:26 AM
#15
Burning Brakes
Ken
You may have missed my post about my cooling problem. I have the dewitts rad and elect fan, new everything.
Try this. put you hand over the space between the core support and the radiator and you will, or should feel a large volume of air. Place your hand carefully between the engine and radiator and you will feel air movement. Now seal or block the space between the core support and radiator and you will not believe the increase in air movement, and I mean, big time between the radiator and the engine, made a big difference in the temps in my car. GM put a seal in the area on later cars to include big blocks, check your catalogues. One of our members sent me a photo of a seal he placed under the car on the lip of the fiberglass in front of the core support to help stop air escaping from under the car while driving. I found the perfect seal for this at a junkyard in a ford suv rear hatch. The section that attached to the suv attached like it was made for our car and the other side that sealed the door on the suv filed up the open space in front of the lip. I think the idea here is to stop air from being sucked away from the radiator by the movement air below the car.
One more thing make sure your temp sending unit is 25 ohms will give you 180 degrees. I had picked one up not knowing the difference and it was way off. You need to have access to a IF gun to make sure of you no's. mine is runing at a constant 200 in 95+ degree weather here in the desert with the air on in traffic.
Give us a thumps up if this helps, would like to hear you had the same results.
Dennis
You may have missed my post about my cooling problem. I have the dewitts rad and elect fan, new everything.
Try this. put you hand over the space between the core support and the radiator and you will, or should feel a large volume of air. Place your hand carefully between the engine and radiator and you will feel air movement. Now seal or block the space between the core support and radiator and you will not believe the increase in air movement, and I mean, big time between the radiator and the engine, made a big difference in the temps in my car. GM put a seal in the area on later cars to include big blocks, check your catalogues. One of our members sent me a photo of a seal he placed under the car on the lip of the fiberglass in front of the core support to help stop air escaping from under the car while driving. I found the perfect seal for this at a junkyard in a ford suv rear hatch. The section that attached to the suv attached like it was made for our car and the other side that sealed the door on the suv filed up the open space in front of the lip. I think the idea here is to stop air from being sucked away from the radiator by the movement air below the car.
One more thing make sure your temp sending unit is 25 ohms will give you 180 degrees. I had picked one up not knowing the difference and it was way off. You need to have access to a IF gun to make sure of you no's. mine is runing at a constant 200 in 95+ degree weather here in the desert with the air on in traffic.
Give us a thumps up if this helps, would like to hear you had the same results.
Dennis
05-31-2007, 01:44 AM
#16
Melting Slicks
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Ken,
get in the g-d car and drive it..... screw all this high temp, low temp crap. Since when do you not know how to chnage a thermostat and fill a radiator and expansion tank. These cars are not a mystery...... lower the collant level so as to not loose too much when you open the themostate housing, change to 180 or what ever you think is the right temp, button it up, add some coolant fire it up and top it off as needed....... the hot rod was no different, remember?
Then drive like the wind buddy...... got it? good.
Might be your neighbor soon. Looking to move to Napa Valley area. Wife has a great job oppotunity.
get in the g-d car and drive it..... screw all this high temp, low temp crap. Since when do you not know how to chnage a thermostat and fill a radiator and expansion tank. These cars are not a mystery...... lower the collant level so as to not loose too much when you open the themostate housing, change to 180 or what ever you think is the right temp, button it up, add some coolant fire it up and top it off as needed....... the hot rod was no different, remember?
Then drive like the wind buddy...... got it? good.
Might be your neighbor soon. Looking to move to Napa Valley area. Wife has a great job oppotunity.
05-31-2007, 10:34 AM
#18
Le Mans Master
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Ken,
get in the g-d car and drive it..... screw all this high temp, low temp crap. Since when do you not know how to chnage a thermostat and fill a radiator and expansion tank. These cars are not a mystery...... lower the collant level so as to not loose too much when you open the themostate housing, change to 180 or what ever you think is the right temp, button it up, add some coolant fire it up and top it off as needed....... the hot rod was no different, remember?
Then drive like the wind buddy...... got it? good.
Might be your neighbor soon. Looking to move to Napa Valley area. Wife has a great job oppotunity.
get in the g-d car and drive it..... screw all this high temp, low temp crap. Since when do you not know how to chnage a thermostat and fill a radiator and expansion tank. These cars are not a mystery...... lower the collant level so as to not loose too much when you open the themostate housing, change to 180 or what ever you think is the right temp, button it up, add some coolant fire it up and top it off as needed....... the hot rod was no different, remember?
Then drive like the wind buddy...... got it? good.
Might be your neighbor soon. Looking to move to Napa Valley area. Wife has a great job oppotunity.
I was thinking of draining the coolant and replacing it at the same time as I have no idea if and when it was ever flushed and replaced. Good time to do it I suppose? I built the hotrod so I knew every inch of it, still trying to figure out Corvettes. SO GIVE ME A BREAK! LOL
06-03-2007, 09:29 PM
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Le Mans Master
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Well, drained out all the old coolant, pulled the thermostat, just as I suspected, a 195* thermostat. Since I live in the Sacramento valley where summer temps avg 95* I replaced the 195* stat with a 160* stat. I know you guys don't like anything lower than a 180* stat but I will see what this one does for my car and I will be adding A/C soon as possible. Going to let the RTV silicone dry for 24 hours and will see if I can get her hot tomorrow. Would like to see temp down around 180* to 190*.
06-03-2007, 10:13 PM
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Melting Slicks
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Geeze - 195.... where'd that motor run before you got her, Alaska in Janurary? You'll be OK with the 165 in CA - gets pretty warm there and when you add the A/C you'll be thankful for the lower intital temp.
Drive on Ken
Drive on Ken