Cleveland Thermostats

PD -
This subject has been debated in the past, and here's what I think I know:

A regular Ford thermostat will fit, but is missing a "hat" shaped part that blocks off a bypass. Without this bypass blocked, coolant will recirculate in the engine without passing to the radiator, leading to sub-optimal cooling or overheating.

It has also been stated that running with no thermostat, like running with the incorrect thermostat, will lead to HOTTER conditions than running with the proper thermostat. Again, if you are missing the "hat" that plugs the bypass function, a certain percentage of coolant will not pass through the radiator.

There are certain aftermarket water pumps that accept a standard Ford thermostat.

Bottom line is that you need to run the proper thermostat for the application in order to optimize the cooling system. Personally, I'd run with a little higher temperature thermostat. I run 192, which I've read is actually a healthier temperature for the Cleveland. A 160 degree thermostat will open at 160 and just stay wide-open, more or less.

Here's a discussion on this board which helped me:

Cleveland Thermostat

And another:

Cleveland Thermostat

flow kooler sells the proper thermostat, a Robershaw model.

George

What I find curious is the choice of 180* (or higher) thermostats on Pantera. I understand that the purpose of the thermostat is to regulate coolant flow controling heat absorbsion/transfer, but given the 180*, won't the fans run before the thermostat fully opens. Seems that the fans and thermostat would be in contention, with the fans trying to keep the thermostat (at least partially) closed. What is the downside of running a 160? Wouldn't that allow full flow through the cooling system allowing the temp sensors/fans to regulate temp to the best of their ability? Sorry for the questions, haven't owned a Cleveland motor since 1973 (first car a '71 BOSS351). Thanks

The fans shouldn't come on at a significantly different temperature than the thermostat, or you'll have exactly the condition you are describing.

I'm going completely by memory, but I thought that the fans turn on at 188F or something like that? I'm running a Robert Shaw 192 thermostat, and my sensors in the radiator recently died. Currently, as a makeshift solution, they are wired to run all the time. But when I replace the sensors, I'll probably replace them with roughly a 195F sensor. That way, on the highway the fans won't run as the temp should (theoretically) be 192F. When I pull off the highway, the coolant temp will rise to 195 when the fans will kick on.

On the subject of what temperature thermostat to run, I asked Gary Hall. He said that in his experience (I personally consider vast), because of the design of the Pantera system with the radiator in front, the engine in the rear and the length of the attaching pipes, if you run a 195 thermostat, by the time flow starts to the radiator the engine can over heat. The problem fix is simple, run a 160.
Although I respect everyones opinion here it is immpossible for me to not give Hall's opinion more weight.
I can't immagine running a 195 in a Pantera.
Hall thought that it was "typical" to have the engine red hot with a 180 and the radiator cold.
I think that the water temp in a Pantera will be 195-200 with a 160 when everything is right. That's where I want the water temp.
The cooling fans have nothing to do with the engine temperature. They cool the radiator, the radiator cools the engine. The coolant has to get there first.
Frankly I think that if you are not running synthetic oil in a Pantera you are very foolish.
The synthetic oil will eliminate the wear you are all affraid of. It won't ever break down. Conventional oil will.
The signifigance of the engine temperature to oil is to raise the temperature high enough to eliminate the sludge in the oil caused by water vapor naturally accumulated in the oil. Boil it off.
Unless your oil temperature constantly rises to above 212F, you are going to have sludge. Your water temp would be about 20 degrees hotter then the oil at that point, about 232. That is not what I want.
I would rather change the oil then risk over heating the engine.

quote:

Originally posted by Charlie McCall:
The fans shouldn't come on at a significantly different temperature than the thermostat, or you'll have exactly the condition you are describing.

I'm going completely by memory, but I thought that the fans turn on at 188F or something like that? I'm running a Robert Shaw 192 thermostat, and my sensors in the radiator recently died. Currently, as a makeshift solution, they are wired to run all the time. But when I replace the sensors, I'll probably replace them with roughly a 195F sensor. That way, on the highway the fans won't run as the temp should (theoretically) be 192F. When I pull off the highway, the coolant temp will rise to 195 when the fans will kick on.

The prints I have suggest that there is a 158* rfan relay as well as a 176* relay. The is also a note "with a 180 degree F thermostat, both fans will run continuoisly when the engine is a mininum normal operation temp".

Doug, Charlie, Josh & John,

We've discussed the Cleveland lubrication system. We've discussed the Cleveland block. We've discussed the Cleveland heads. We've discussed a scenario for making 500 bhp while maintaining relaibility & drivability. We've discussed the the cooling system built into the Cleveland motor. Perhaps the next thing we should discuss is the cooling system built into the Pantera. But we'll save that for another day OK? Too tired today to sit and type a 6 paragraph technical piece. I'll step on the established toes another day.

I do not buy into the notion that a motor with a 160 degree thermostat can be over 200 degrees? By 165 or 170 degrees the thermostat will be wide open, maximum coolant flow. The thermostat is located in the motor, measuring the temp of the coolant immediately as it flows out of the cylinder heads. If it is wide open by 165 or 170 degrees, the radiator inlet should also be close to 165 or 170 degrees. The Pantera is a mechanical device that must adhere to the laws of physics. Lets not get all metaphysical here, OK? Grand poobahs, wizards, and the Pantheon of Pantera gods aside.

John's specs for the temps switches are pretty much correct , the right hand tank of the radiator, where the temp switches are mounted, is split in half, the lower tank being the radiator inlet (warmer), and the upper tank being the radiator outlet (cooler). As per the Pantera parts list available to me (in an older PI Motorsport catalog), the temp switch screwed into the radiator inlet was set at nominal 185 degrees F, the temp switch screwed into the radiator outlet was set at nominal 158 degrees F. The Cleveland came with a 192 degree F thermostat, which in effect meant the fan controlled by the inlet switch was intended to run full time after the motor warmed up.

John's 176 degree F setting for the inlet tank switch is probably based on Bill Taylors schematics, which may be accurate for the later cars. However a 176 degree switch, even with a 180 degree thermostat, still results in the fan controlled by that switch running full time once the motor reaches operating temp.

All for now. Hope each of you are enjoying your weekend. Dougo, his son & I spent the day hanging out together.

Your friend on the DTBB, George

PS, Mark, your avatar gives me the heebee jeebees.

Oof. I had assumed that the thermoswitches in the radiator were set to turn on at a little higher temp than 158... as you state, they will stay on 100% of the time, which really defeats the purpose of having a thermoswitch to turn them on and off...

I respect Gary Hall as well, but I have a tough time believing that at equilibrium, in a healthy cooling system, there will be a 40 degree difference between the motor and the radiator. I maintain that in a healthy motor and cooling system, the engine coolant temp should stabilize at the thermostat temperature. If it doesn't, then you've got a problem with your cooling system, and it is probably more complicated to solve than simply installing a different thermostat.

Where does one find a 160* Cleveland thermostat? I only see Robertshaw listings at 180* and 192*. Thank you

As far as I know there are no 160 degree "Cleveland" thermostats. What you can do is call Pantera Performance Center in Castle Rock, CO and buy their 160 degree thermostat kit. You will get a 160 degree thermostat plus a "plug" to put in place of the "orifice" that is in the Cleveland thermostat housing. The plug kit eliminates the Cleveland recirc feature and allows you to use a conventional thermostat. I put this on my car and it seems to run fine with a stock radiator and stock 8 bladed fans. I have one fan switch on my car in which the contacts close at 178 F and open at 160 F. The other is manually controlled by a switch on the dash (early 71). I rarely if ever use the manually controlled fan. Both Gary Hall and Dennis Quella, two of the most knowledgable Pantera people in the country, both recommend a 160 degree thermostat. I would say 160 is the way to go!

The thermostat doesn't control the temperature of the engine coolant. The cooling system along with the ambient air controls the engine coolant temperature. If you have a 180 degree thermostat it will be completely open around 180 degrees but the engine coolant temperature will continue to rise until the cooling system reduces the temperature of the coolant. If the cooling system cannot "keep up" with the increasing temperature of the coolant, the coolant just gets hotter and hotter. That's what Gary Hall meant by having a 160 degree thermostat and the coolant running 200 degrees.The Pantera cooling system cannot keep the coolant tempertature at 165 degrees. The Pantera cooling system is a nightmare. Swirl tank, numerous 90 degree bends, elbows that reduce the diameter of the cooling tubes, small diameter cooling tubes, transitions between tubes and hoses. It's difficult enough cooling a mid engine car without all the Pantera's cooling system bottlenecks.

One big bottleneck is the thermostat. I'm using a Robert Shaw 180 degree thermostat that I modified with 3 3/16" holes like Stewart Components does to the Robert Shaw thermostats they sell. It did make a difference.

http://www.stewartcomponents.net/Merchant2/merchant.mvc...&Category_Code=Therm

If the thermostat is wide open & the coolant temp is climbing, you have a problem! In that case, a 160 degree thermostat is NOT a cure. Sure, the thermostat will go wide open sooner, but the heat removal capacity of the system remains the same, and the temp will still climb under the same circumstances. Removing the thermostat all together will remove a restriction and thereby improve coolant flow a bit, but a lower temp thermostat does not help remove one additional btu from the coolant.

In a properly operating cooling system, the thermostat most certainly does control the temperature of the coolant. Like the oem system in my Pantera, which regulates temp most happily at 192 degrees F. I fully agree the system is marginal. I'm not happy with the marginal performance and shall fix the shortcomings very soon. And share the whole process with the bulletin board.

We should avoid turning this into a "Gary Hall & Dennis Quella says such and such" pissing match. That reminds me of the crap that transpires on the mailing list. This is not about personalities & personal heroes. Please understand, I don't want to cast dispersions towards anybody. I respect those gentlemen too. But by bringing names into the discussion like that, you're setting us up to do just that if somebody disagrees with them. I refuse to be drawn into that situation. I can respect somebody but still believe they are wrong about a particular issue.

I would prefer a good written debate where principles of engineering are discussed. Quoting somebody you respect does not prove the point you may be trying to make. The only reason I can see for doing that is to attempt to end the discussion.

I can see that the Pantera's cooling system is a touchy subject for some. I'll try to respect that, but at the same time, if there are any "myths" floating around in the Pantera community, I would like to bust them, how about you?

quote:

Originally posted by johnk:
Where does one find a 160* Cleveland thermostat? I only see Robertshaw listings at 180* and 192*. Thank you

John, to my knowledge, there isn't a 160 degree t-stat on the market for the Clevo, those are Windsor t-stats.

Your friend on the DTBB, George

Are you going to make me pull mine out of the car? Mine is from a NAPA store. Walked in, asked for it, got it. Just like the Skippy Peanut Butter show, "You asked for it, you got it!"
Hum... maybe mine is now one of those classic parts you can't get any more. Ok, it's going on ebay.
As I said, the Cleveland is (has) become somewhat of a dinosaur. Little things are disappearing like thermostats and water by-pass holes.
All I said about Hall was, how can I ignore what he said? What I ask the jury to do is to consider all of the evidence placed before them.
As Rod Serling said, "for your consideration..."

The last thing I want to do is piss in somebodys cereal,but if the thermastat opens at 180* at the motor,how hot will the engine get as the water circulates and come about.Eventually the system will stabilize, if the system is in proper working condition,and all remains smooth.The pantera system does have a long route to go from engine to radiator back to engine to radiator and so forth.By installing a 160* thermastat,it just starts the journey sooner.Now,thats just my opinion,so please don't piss in my cornflakes!Just kidding!I think this is a good discusion.

I don't care who's right as long as my car works. You can bring a horse to water but that doesn't make him a duck.
(Don't ask me what that means I have no idea).
Just as an asside; do you think that your Italian water temp gauge works accurately with your "Detroit" water temperature sender? Hum? Stop it, stop it...stop asking questions!

quote:

Originally posted by jwr2968:
if the thermastat opens at 180* at the motor,how hot will the engine get as the water circulates and come about. The pantera system does have a long route to go from engine to radiator back to engine to radiator and so forth.By installing a 160* thermastat,it just starts the journey sooner.

How much coolant does the Pantera's system contain? Possibly 5 gallons? If the pump is pumping at 15 gpm at low rpm, the coolant is circulating 3 times per minute, or making the "loop" every 20 seconds. At higher rpm the pumping rate is more like 40 gpm, in which case the coolant is making the "loop" every 8 seconds. (those pump rate figures are from Edelbrock's web site)

My oem system has a 192 degree thermostat, the temps stabilize at 192 degrees, there's no overshoot or off set.

quote:

Originally posted by PanteraDoug:
do you think that your Italian water temp gauge works accurately with your "Detroit" water temperature sender? Hum? Stop it, stop it...stop asking questions!

Ford installed a 10 ohm resistor in the circuit to make it read properly at the normal setting (192 degrees). Besides, the instrumentation in cars back then wasn't that accurate. Many US built cars didn't have numbers on the gages at all, just bands of color.

Your friend on the DTBB, George

quote:

Originally posted by PanteraDoug:
Just as an asside; do you think that your Italian water temp gauge works accurately with your "Detroit" water temperature sender? Hum? Stop it, stop it...stop asking questions!

The only way to find out if how accurate YOUR gauge is is to stick some kind of thermometer in the swirl tank and fire up the engine... I used a meat thermometer. You don't want to rev the engine or the coolant will spill, but just let it gradually warm up. You'll need to wait until it reaches at least 192 degrees for your thermostat to open ;-P Just kidding. Peeking through the rear window, you'll have an idea of what kind of temp differential you have between "real" reading and "DeTomaso" reading. I just add 20C to my coolant reading and I know what my actual coolant temp is. I suppose it probably isn't perfectly linear, but I don't lose sleep over it.

Meat thermometer? Add 20 degrees? How do you know when to turn the meat over? Must have something to do with the latitude?

Charlie, a thought came to mind that made me chuckle, was your car rare, medium, or well done?

lol...............

George

Here's some rambling thoughts on Temperature senders for consideration;

The Temp sender unit is a simple resistance switch, that indirectly measures the temperature, where hotter T = higher current flow and should not (in auto applications at least) be considered a precision instrument. The resistance method in itself has some degree (pun intended) of inaccuracy.

Have you thought that the gauge and sender need to be matched? There are a large number of different ohm range temp senders and 'full current' temperatures, e.g. Temp sender is 'full current' at say 220F, where 'full current' on the gauge is 260F which gives an immediate bias or offset.

As with the t-stat discussion the Temp sender is Cleveland specific (Part # TS58 I beleive) and if another or generic sender unit has been used then a bias could easily exist.

By establishing the bias or offset on an existing temp sender to gauge pair you could theoretically 'correct' this by obtaining a temp sender unit with different ohm range/full current T.

I'm assuming that everyone has their Temp sender located in the block (water pump housing) and no-one is still running with the sender in the pressure tank?

Julian

I have a 180* thermastat that works correctly because I checked it before I installed it.My temp. gauge reads 157* when my car warms up and my thermastat opens because I can hear it and feel it.So what you are saying is ,this is normal.Thanks,it verifies what I was thinking.

jwr,

your gage is reading 23 degrees low. too much resistance somewhere. perhaps a bad sender, a loose or dirty wire connection.

George

So if I use a 160 thermostat, my meat will be to rare? Bet you a nickle that all your temp gauges are off 7 to 10 degrees. (now was that c or F, ah sh..?) Pass the meat tenderizer please.

lol.........

OK Doug, I'm accustomed to your humor now.....

and I'm liking it.

But on the subject of your meat, well.........

isn't that a little too personal? lol........

George

Thanks George and all the guys who posted pictures of the thermostats. I just got around to pulling my stat out and it was one of the "one size fits all types" that came from NAPA. I think the part # came from this site somewhere a few years ago but the Robertshaw/Flowkooler application is the correct part. The NAPA part # was 297 and the FlowKooler was 333-180. As soon as the wind chill goes above 0 degrees and the salt disappears from the roads, I'll be able to take the car out and test it. Thanks again everybody. Vince