Engine temps on a flathead

[Downerman]

Posted originally in the civilian area bit no response. REally just wanted to know where you guys see your engine temps.

:So I bought a 1946 that had a newer model engine in it that was basically dead. The deal also included a completely rebuilt 46 flathead. The gentlemen I bought this from has a machine shop and a hunting club on his mega acres property. At one time he had a dozen or so old jeeps for the people who paid to hunt there. I got his last one as the hunting has stopped nearly 12 years ago. So that being said, I have the 46 flathead engine now in the jeep. Bought a new carb from Ron along with a new distributor and other various parts. The engine runs really well. It starts right up and idles to the point where I can't hear the engine ... well almost. Great oil pressure and it's charging perfectly now (After some tinkering to get the new 8 volt battery and regulator to jive). The jeeps old hood has a large square box to accommodate the newer model engine's (that was dead) carb/air cleaner so I took the hood off. The engine would run and overheat not 5 minutes down the road. I messed with the timing until the car ran at @ 180 and would occasionally peak to 200 under heavy climbing and I could drive it all day. I thought this was pretty good until I just bought a new hood from Ron, installed it and took the jeep for a spin. Hit 200 and then 220 on the same road, doing no more than 40 MPH. When I got back to the ranch I hit it with a digital temp gun on the radiator and the return on top of the engine. The hottest I could get it to was 210 so the gauge was showing it 10 degrees higher than reality. So, not knowing squat about this little gem, I do know that on my sports/muscle car that 210 is optimal. That's exactly where you want to be with that 351 Cleveland and your best performance is there. Or so say the gear heads on the 351 forum.

Original Radiator, cleaned and repaired. All new hoses. Fan installed correctly.

Where do you guys see your temps at?

Dave

[SB5477]

Depends on thermostat and other circumstances normal running temperature is between 160-180 F.

[Michael Browne]

Hi Dave,

What sort of temp was the day you drove it? 40 mph on a mild day (20C) will all things right would have it about 160-170 depending on what thermostat is installed and the state of tune, condition of the gas etc
There are a multitude of things that will push the temp up, best to start with a good tune and work your way up.
You may also have partially blocked your 'cleaned' radiator with crud from the rebuilt engine, particularly if it has been sitting for a while. Try opening up the water drain tap on the block and see if you can get a good flow of water. This will tell you if the block is full of sediment.

Good luck

[Downerman]

Wow... you guys are running cool. I purchased a thermostat from Ron but ended up taking it out when these heat issues were worse. To answer your questions it was mid day, maybe 80 degrees outside. I can see that I'm way to hot still. I did order some new insulation (Around the radiator) from Ron as mine is all missing. Also got a new radiator cap because even though it says "10" on it I think it letting pressure out way sooner than it should. It seems old and worn (The spring and gasket). If these don't get me down than I guess I adjust the timing even more.....

Thank you all for your comments.

Dave

[Ben Dover]

Your cooling system requires a 4# Cap, you did not indicate the rating for your thermostat and you indicated the spring in the cap and the gasket are worn. Are you installing a new 4# Cap, and does it have a rubber seal made to it? If not you will have to install a new fibre gasket in the radiator filler seat for the cap.

[artificer]

Reading through what has been written those temps are too low & you need to be running @ about 190*F.
If this engine was rebuilt & as "new" the block would not be full of sediment, but it may be worth checking.
One thing missed & not asked is are you losing coolant? No then you are not boiling & if you are not boiling you are not overheating.
Can you squeeze either of the radiator hoses when engine is hot & they feel tight? If so the radiator cap is fine & holding pressure.
Another thing is when you turn off the engine there will always be a heat spike, that is normal.
Do not continually fill the radiator....topup to about 1/2" over the top of the tubes, only about 1/4 of top tank.
With todays grades of fuel most Jeeps are running retarded, if set by the book/timing marks.
Try advancing timing @ least 5* extra....even up to 8* & check for pinging [load in top gear going up a hill] if none you will be running cooler plus getting more power & improved fuel economy to boot.
You can, as I & some others do, adjust timing to optimum using a vacuum gauge.

[Maurice]

When turning the distrib to advance or retard the timing which way is advancing and which is retarding? I set my timing by ear but never used a light. Thanks.

[SB5477]

I set my timing by ear but never used a light.

You should. Can not be set exactly by ear. Repeatability will also suffer. You also need a timing light to see if it is advancing properly. If you turn it the way of rotation it is getting retarded, against rotation will be advanced. Some people are not using torque wrenches either, they say its in my hand and end up with over/undertorqued fasteners.

[Ben Dover]

Diy you install a lower temp Thermostat, a 160F would be a good start.