Sounds a little hot. I have a failsafe one the kicks in at 170 degrees. Got it from AutoZone. Don't remember the brand though. My temp sits at 170.

 

207* is a bit high for an operating temp. Factory EFI uses a 195* thermostat, and should run about 200* or so.

My engine has a pretty high compression. Keeping it cool helps prevent detonation. I like to see the temps well below 200*. Preferably 160-180*.

The thermostat only sets the minimum temp. The first question to ask is if the temp gauge is accurate. If so, does the thermostat fully open? If so, is the cooling system adequate for your engine?

 

Small block punched out to big block

would necessitate a radiator/cooling system for a big block . . . first rule of cooling, never try to cool a 427 with a 289 radiator. If your rad is of sufficient size and capacity for the engine you are running, then I would look at the T-Stat rating. No reason to not run a 160° to 180° T-Stat in your engine . . .

I would remove the T-Stat and test it with a known good thermometer on the stove in a pan of water, making sure it opens fully and at what temp. If it's not performing correctly or the temps are too high, replace it with a lower opening temp unit. Your not on EFI so no need for the higher 195° stat.

You wouldn't be the first person to have a faulty T-Stat right out of the box.

Doc :beerchug:

 

What do I ask for at the parts store? If I tell them I need a 160 ford t-stat, will that be enough?

 

is that 207 sitting in the garage or driving around...on a 195 t-stat I would not be too excited about 207.. does it cycle down to 195-200? you might still have air in the line? The engine is also pretty new right? they tend to run warmer when they are freshly built...it is a tad warm but at least it will help get the oil up to temp and burn off the water in the oil. Mine has a 195 and will get up to 208-210 just sitting in the driveway until the fan kicks it down to about 195...at speed I am around 200-205...

Get all the air out of it put some water wetter in it and recheck.

 

its a stroked and bored 351w correct? was it flushed after you broke it in?
you could install a temporary gauge and check the difference.
the t-stat @ 195* is what they ran in the EFI windsors
try a 180* stat may have to drill a small 1/8" hole in that temp stat because normally they come on the 195* stats. this helpd bleed fluid to both sides of the stat when its close and helps keep it lubed on the engine and radiator side.
also what happens with the 427 strokers is they get hotter because the bore getting closer to the water jackets.
check also for air in the line still, another option is add water-wetter to the anti-freeze.
make sure your fan is getting the right amount of voltage for its speed.
good luck and happy pedal mashing:evil:

 

This should help you. I would recommend a Motorcraft thermostat but whatever you chose, test it in hot water with a thermometer before installing it.

Frank

 

I'm with Erik on this. That isnt too hot for a modern engine. Cant understand why everyone frets about the engine running at 200*. I bet you dont have a clue as the operating temp of your daily driver.

 

Because this is not a modern engine. It's an old fashioned American V8, using the same rings, bearings, push rods, carbs, and blocks that we used 20 years ago.

200* is not too hot. But it's hotter than it needs to be. By running the coolant that hot, you're also allowing the heads and coimbustion chambers to be hotter than they need to be.

IR carbs are not always that consistent, and they can occasionally run a little lean. If the combustion chambers are cool, that brief episode of lean mixture is no big deal. But if you're already over 200*.... now it's a big deal.

To run efficiently, you really don't want the engine much above 220* or so. If you're already at 207*, you have very little margin for error. How long do you have to sit in traffic to gain 20*?

I know exactly what the operating temp is on my DD.

am i supposed to drain the cooling system after breakin? How many miles? I did not know this!

I never do. But I make sure I clean out the coolant passages before assembling the engine.

 

am i supposed to drain the cooling system after breakin? How many miles? I did not know this!

 

I think that a 180 degree thermostat is most commonly used with carbureted engines, as stated earlier, modern fuel injected engines generally run a 195 degree thermostat. How sure are you that the gauge is reading correctly? If you think that your radiator may be undersized try turning your heater (assuming you have one) on and turn the heater blower fan on high, if it cools down a few degrees your radiator may be under capacity or partially blocked. If your cooling system is marginal ignition timing that is too far advanced may contribute to the problem. If you know someone with a hand held pyrometer try taking temperatures at different points of the cooling system. I assume your cooling fan is operating properly although I didn't see any mention of it. is it operated manually or by sensor?

 

"Because this is not a modern engine. It's an old fashioned American V8, using the same rings, bearings, push rods, carbs, and blocks that we used 20 years ago. "

Bob, I think he has a 427w ford crate motor...I would guess that the internals are not the same as they were back in the older days. Additionally, ford put 195 t-stats in the crates as far as I know. At least that's how mine came from ford.

I would think that the t-stat range I think when you talk about modern cars has more to do with the tune within the ECU more than the materials used. The ECU is trimmed to run without fuel adders within certain coolant temps...simply changing changing t-stats on EFI engines could cause EFI engins to run cooler and thus probably richer based on their coolant fuel maps..

I go back to my very first questions....

is that 207 sitting in the garage or driving around??

Simply throwing out a temp without understanding the conditions we are seeing this temp or how many miles are on the motor is probably not enough info to execute a plan in either direction.

anyway, it is just my opinion.....

take care.

here is a thread from earlier in the year...it comes up again and again from time to time....

http://www.ffcars.com/forums/17-factory-five-roadsters/288155-how-hot-does-your-engine-run.html

 

Sorry Bob your wrong, this is a modern engine, built using the highest quality alloys and machine tooling. Sure the block may be similar, but the pistons, rings and bearing, gaskets etc, are all far and away superior to anything build 20 yrs ago. The difference between 180* and 200* dont mean anything if you go lean.

 

Go back and look at the specs for the "new" 427W from Ford. Sure, they use "modern" materials. But they're not that far off from a block or pair of heads from the 70's or 80's. Also, look at ring and bearing materials. Nothing all that much different than 10-15 years ago.

Rings, bearings, clearances tolerances, etc, all pretty much the same as they have been for the last 20 years. Pull out Pat Ganahl's or Tom Monroe's book (written in '79 and '80), and compare them to a book written in the last few years. Not much difference.

The other question you have to ask is why are modern EFI engines designed to run at 200*? Are they more efficient? Do they last longer? Get better fuel mileage? Make more power? No, none of those. It's simply to lower emissions.

Take a look at the new Corvette. If you want to get good power out of them, the first thing you do is change the thermostat and reprogram the computer to accept the lower operating temps.

Other data tells us that engines that run below 160* have accelerated cylinder wall wear.

Perfect operating temp for a gas engine is around 170-180*. That hasn't changed over the last few decades.

 

Correct again.

QSL. Considering the way you'll be using your car, a warmed up operating temp over 200* is simply not a good idea. There's simply no room to go wrong at those temps. As stated, if you find yourself sitting in traffic your engine could be toast in no time. Keep in mind also that there's really nothing "modern" about your engine in regards to how it operates. Consider the recommendations above and try to bring the temp below 200*.

 

I have an electric fan. Its what came with the complete kit. It seems to turn on about 190 or so?

I drove it again tonight and really watched the gauge... It peakes at 210. but then it goes down to 180. I would say on average it stays in the 195 range, but it goes up and down while just cruising in the neighborhood.... It gets to 190 or so and the fan comes on... it goes to 210 and then starts to drop until it gets to 180 and then the cycle starts again. Seems to me that the major problem is that i am doing cruising in the neighborhood. I need to get on the freeway and get a consistant temp. Next week i am going to chp so i will know for sure then.

 

i still think you may have an air pocket
prop the front of the car up "not running of course":evil:
cold engine open up the radiator cap. let it sit like this overnight.
i bet in the morning you will see that the fluid dropped.
fire it up for a few minutes with the cap off still, shut her down let it sit for a bit, add fluid.
now put the cap on and bring it up to operating temp 192* is a sweet spot.

your radiator cap is high on the engine isn't it?

and as far as flushing a new engine i am a big camper on this, oil, anti-freeze changing in the first early miles will remove tailings from any machining, if you ever put a new set of heads on 90% of them need to be flushed thru the water jackets prior to install. last set i purchased i could not believe the aluminum millings that came out of the cylinder head.
as far as oil the new engine gets its breakin oil, then new oil. and about 500 miles another change. also a good idea to put a magnet on the oil filter to collect fine machining.
on initial engine breakin (on the water side) i prefer to see distilled water only, in case of leaks there is no green monster leaking on the new parts.
i have 4800 miles on this engine and the oil and fluid has been dropped several times. once because i had to pull the drivetrain because of a brand new tko-600 leak, and thats another story.:evil: someones ears are ringing right now:001_rolleyes:

 

Lexus runs their engines in the mid 180s F. For me 200 is a little on the hot side if that is at cruise speed.My 351 stays at 180 until I get into traffic and then it may get to 200.

 

While the old vs new debate continues on let me add a couple comments. Aluminum head engines like a bit more heat than their iron headed counterparts to make best power and can do so without fear of detonation everything else being equal.

Now that we've got that out of the way here's the BUT: If my temp was reaching 210° just puttin' around the neighborhood I might be asking questions like you are. Keep in mind that short blasts at low speeds don't move much air through the radiator so you will see some temperature creep even with the fan on. How much depends on how much your nerves can take. From your description though it sounds like the parts you have in place are all working as they should. Temp goes up, T-stat opens, temp goes up some more, fan kicks on, temp goes down.

For a carbureted, aluminum head mostly street driven engine under spirited conditions I'd pick a 192° thermostat. For sustained high speed track flogging I'd pick a 180°. The key as I've indicated earlier is to check them first to make sure they open as they are marked.

For the time being, do as you indicated. Drive it on the street and freeway at speed and see how it behaves then decide from there what to do next. HTH

Frank

 

thanks guys... I am thinking it could be an air pocket. Last night before taking it out, it was low. I topped it off and ran it. After cool down, it was low again. So i topped it off and let it sit with the cap off. A couple hours later I checked again and it was low so i topped it off again. This morning it was low again so i added some more. About a half quart... So I will see tonight what the status is. Either there is a air pocket or a major leak which i see no evidence of.

 

thanks guys... I am thinking it could be an air pocket. Last night before taking it out, it was low. I topped it off and ran it. After cool down, it was low again. So i topped it off and let it sit with the cap off. A couple hours later I checked again and it was low so i topped it off again. This morning it was low again so i added some more. About a half quart... So I will see tonight what the status is.

Those symptoms are consistent with trapped air which can cause issues.

What fan shroud are you using?

 

I think this was mentioned earlier, but the first thing I would do is verify the gauge reading using a known good gauge. If the gauge is reading correctly first check the thermostat. if the engine is exhibiting large swings in coolant temps, it could be a partially stuck thermostat. Next verify that you have the correct rotation water pump for your application. You may also want to check the radiator cap for proper function. You can also check for coolant flow, remove the rad cap on a cold engine and start it and let it idle until warm. Observe the flow through the rad filler, you should see a good amount of flow when the thermostat opens. Look for excessive bubbles or foam that may indicate a leaking head gasket.
You didn't mention the temp that the fan(s) come on, they should be at the same temp that the thermostat is designed to open. I personally prefer a 180º thermostat for a carbed engine and a 192º for a FI engine.

If everything looks good and it is still running hot, you may need a bigger radiator and/or a higher flow fan.

Some have problems with air bubbles and need to burp their systems, however a degas tank will solve that problem

 

Using the shroud from breeze.

 

Adding coolant

" Either there is a air pocket or a major leak which i see no evidence of. "

Water leaking into an intake port thru a bad intake gasket will NOT show its ugly head.
Water is pulled into the intake charge and [sorta] burned and exhausted with the rest of the combustion mixture.

Do you have a coolant recovery system in place, one large enough to put back what is being pushed out during normal engine operation? If its too small, it will push coolant out and then overflow. When the engine cools down and pulls back what has been sent to the coolant recovery tank, there won't be enough coolant and the system will draw in air.

I had this exact issue with mine, engine was pushing out 30 Oz. into a 24 Oz. container . . . OOPs! I was adding about 8 Oz. every time I went out in the car. I now have a 36 Oz. overflow tank on order.

FWIW, I run the factory stock 192° stat in my EFI engine, car runs at 85°C consistently, moving up to 90°C in traffic, in the heat of the Las Vegas summer.

HTH

Doc :beerchug:

 

Right now, i have the stock overflow that came with the complete kit. However, i do have one twice the size on the shelf. But i have not experienced this one dumping coolant on the ground yet.

 

Can I ask you a simple question what radiator are you using? I have a 427 too running a 180 thermostat, Ron Davis Radiator with a built in oil cooler, dual fans. I run a fairly stable 180 Usually only one fan comes on as there set to come on and go off at different temps using the engine management system.If I watch the temp gauge I like you can see the gauge go up when the thermostat opens but then falls back as cool water is drawn in. At highway speeds the fans never com on. Even Idling in traffic it barely reaches 200.

 

QSL: You might be able to change the sensor that turns the fans on and off for one that has a lower range for on/off. You can also install a switch that grounds the relay that controls the fan so you can turn it on any time you want. I installed a manual switch on my 88 Corvette to turn the fans on because it ran very hot 210-220 at low speeds even with a 160 T stat. Not hard to do and it gives you an option for occasional Auto-X or track day use.
Just an Idea:
HTH
CB

 

I did hook up a switch to ground so i can manually turn it on. Gut is telling me air was in the system. I just called home and spoke to julie, she went out to look at scoopy and says that coolant is still to the top of the filler and the last time i filled it was this morning at 6:30am. I am going to get her to operating temp tonight and check it out again.

 

you have to run it to get all the air out of the system. simply topping it off and checking it hours later isn't going to clear any air pockets

Best case would be to pull the temp sensor or a plug at the highest point and then put water in until it just starts to pour out....then fill the overflow halfway, then crank it up and let the t-stat open and close a couple times...shut it off, let it cool down. Next day recheck the fluid at the fill port, top it off and repeat warm up and cool down....repeat as required until you are no longer topping it off...keep the overflow tank half full at all times during this process.

 

The radiator is the aluminum one that comes with the complete MK4 kit.

 

Should be able to cool your motor of your size.

 

When I built my motor, in order to start getting the air out, I put the water pump belt over the chuck of an electric drill, the other end on the water pump and ran the drill for about 10 minutes. This will move some water around in the motor and push out a fair amount of air bubbles. After I did that, I put it all back together, started the engine and left the radiator cap off to vent the rest of the air bubbles, which were minor. Worked great!