What temp should a 200 run at?

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I a little concerned about my rebuilt 200. I don't like how hot it runs. With my handy dandy infrared thermometer, it reads almost 200 degrees near the temp sensor. Too hot?
 
A good deal of people find that for the first 500 to 1000 miles, the engine run ultra hot after a rebuild. Rope seals used for the crank create enormous drag to the free turning of the crank, then the engine loosens up.

Keep monitoring it, and consider placing a different thermostat only if its getting hotter.

Oil temperature is more important than engine temperature. Keeping the sump full and using the engine oil of the weight the builder suggested for running-in is the key.
 
8) 200 isnt bad, i would however prefer to see it run at more like 180. but like xecute said, most engine tend to run a bit hot during the break in period, and run cooler afterwards.
 
IT should run at what ever thermostat temp you have. If you have a stock rebuild and a stock thermostat that opens at 196*, then 200* is pretty good.

Slade
 
Ok, I feel a bit better. But I'd still like it to run cooler. I put a 160 degree stat in in place of the stock 180, which is what the stat catalog said was OE. The 160 seemed to make a huge difference at first, but then it went right back to where it was before I changed. I suppose I should be more concerned about the embarrassing clutch chatter. :?
 
Well, if you have a 160* thermostat, and running 200* (using a mechanical gauge, not the factory dash gauge), you might have some cooling issues. You engine really shouldn't run much warmer then the t-stat temperature provided your cooling system is running up to par.

Slade
 
I'm using a no-touch infrared thermometer. The readings are taken from the area closest to where the temp sender goes into the head.
 
There is a large misconception that lower temperature thermostats will solve cooling system problems. As you mentioned, putting a 160 deg thermostat in a car is not going to affect the normal operating temp, if the engine already operates above a 190 deg thermostat. It will open sooner, and stay open unless you have excess cooling capacity or low ambient temperatures. The thermostat only throttles coolant when the ambient temps are such that the cooling system has excess cooling capacity. With age, scale and corrosion, the efficiency of the cooling system decreases. If your system maxes out at 200 degrees, I would not be concerned. You are well below the boiling point of a 50/50 ethylene glycol mixture.
 
Just as a reference, my bronco runs right at 190 degrees while cruising at about 2800 RPM with a 160 degree stat and stock 2-core radiator. I will eventually put in a 3-core radiator which should lower my temps even more. It will idle all day long right at 160 degrees, which I have proven to myself by the numerous hours of running while fine tuning the engine (in a shaded, well-ventilated area). I have bought an aftermarket flex fan, not installed yet, but only for the hp loss due to stock rigid fan at higher RPMs (doing this to also help with the addition of power steering later, not that a power steering pump emits alot of drag though), you would be amazed at the stock fan's actual drag on the engine at high RPMs. Later.

Kirk ' 73 bronco
 
Yes and no...

If your cooling system is up to snuff, the engine should operate close to the thermostat rated temperature. If you are operating 20-30* above that temp, then your cooling system is operating below normal capacity.

Case and point:
My car, when I first got it, car was running at 225* With a 195* thermostat. replaced water pump, still at 225*. Replaced thermostat to 180*, car still ran at 225*, just got there slower. Found out my radiator was pretty much dead. Replaced it. Now my engine NEVER runs above 180*. That has all be verified by using a mechanical gauge. Heck, if the temps are below 50*, I can not even get it to 180*.

Remember, the thermostat regulates water flow to regulate temperature of the engine. The cooling system should have enough capacity to cool the engine at any given temperature. The thermostat basically regulates when the cooling system is allowed to operate at maximum cooling efficiency (not talking about the car moving, just maximum flow of water through the system at a given RPM). If the thermostat is 100% open at 180*, your cooling system should be able to keep the engine at the temp.

In your case, running a 160* thermostat, and still running at 200*, I think you have some minor flow restrictions in your cooling system. Consider a flush, new water pump, or radiator.

Slade
 
Comet, Don't overlook the possibility of improper ignition timing. The most common occurence is under advanced or retarded timing that will lead to higher engine temperatures. Even if the cooling system is up to snuff with regards to design specs, higher operating temps due to out of spec timing is going to lead to higher operating temps. Make sure the vacuum and centrifugal advance (if equipped) are working as they should.
 
Fastback,
That would be more noticable as the RPM's changed but a good point. I'll bring up a pet project I still can't get anyone to respond to, that's the difference between the cast iron water pumps and the cheaper pressed/stamped impeller ones. I'm of the opinion that the stamped ones have to much clearance between the impellar and the casing causing a vortex and possibly a large reduction in flow. Anyone changing from a pressed to cast one please post any changes they see. Second it was mentioned 50/50 antifreeze mix. To much antifreeze will raise the temperatures as well, the best heat transfer is straight water, but we all know you can't do that do to rust and freezing so use as little as you need to to maintain freeze protection. A lean carb will add to heat problems as well. I put a 2 barrel carb, electronic ignition, headers, and a cast w/p on a 200 at the same time and watched my temperature gauge drop from 50% on the gauge to less than 20%. Problem is I don't know which or if all of it did it.

Steve
 
Steve, retarded timing could cause high temps both at idle and at cruising speed, not necessarily rpm related unless the centrifugal advance is stuck. Your point about carb jetting is just as much of a factor too. With regards to the water pumps and assuming that the clearances are set the same, I would think the cast impeller is more efficient. The cast iron impellers just appear to be a more efficient design versus the cheaper to manufacture folded over sheet metal of the stamped designs. I have not measured the relative clearance between the two pumps. But I suspect the clearances could be more a factor of the rebuilder. You could blueprint the waterpump to minimize the clearance on either design.
Doug
 
Doug your correct, I was refering to the RPM's in relation to the advance curve, even at idle the heat buildup can be quick with the timing off.
I'll try and post a pic of the water pumps here, I still haven't figured it out but here goes, you can see the clearance issues with the impellers.

WTRPMP2.jpg


Steve
 
I was having serious overheating issues until I got the fuel/air mix and the timing dialed in properly. You have to use a decent dwell tach to make it all come together. Tuning by ear will get it to go but once it is dialed in properly the fuel economy will go up, you have more snap off the line AND it will run cooler, much cooler. I have a 180* t-stat with the stock radiator. It will go up on a long grade near here, but only about 10% of the dial. The same setup was boiling over when it was out of tune.
 
Wow, cool. Lots of stuff to think about. I'm pretty sure I set the timing to spec, but cannot actually remember doing it. :lol:

Whats a good method for setting air/fuel mix and stuff?
 
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