| flatcreeker | -- 08-13-2021 @ 12:00 PM |
|
I accepted custody of a well loved and maintained '39 Merc survivor. It runs like a lion, usually. I am new to flatheads and old Fords. It's been a few years since I had a classic and I'm enjoying the learning process and crikey there is a lot to learn. I am wanting to develop a general understanding of what the engine temps should be with a given ambient temp. Here's what I'm seeing. After a 30 minute drive, say, of moderate driving conditions, 40-55 mph, ambient temp 85-88F, high humidity, flat terrain and a mix of up and down moderate hills, I see movement of the temp gauge up and back through the normal range suggesting the 180 thermostats are functioning as they should. When I stop, open the hood and shoot the surfaces with an IR temp gun, I'm seeing 195F on heads just below hose fitment (left and right within 5 degrees of each other) and 250F on intake manifold just below and in front of carburetor and 150F on surface of float chamber. It's the intake manifold temp which startled me. How does all this sound? This message was edited by flatcreeker on 8-13-21 @ 2:40 PM
|
|
| carcrazy | -- 08-13-2021 @ 12:12 PM |
|
A rule of thumb with Ford Flathead V-8s is that the coolant temperature is usually about 100 degrees F higher than the outside ambient temperature, more if the car is accelerating or climbing hills.
|
|
| flatcreeker | -- 08-13-2021 @ 2:43 PM |
|
Thanks for the input. That is about what I thought was typical. It's a bit hilly here in NE Georgia. Do you have any thoughts on the other temps I mentioned (and just edited)?
|
|
| ford38v8 | -- 08-13-2021 @ 7:52 PM |
|
The intake manifold also has an internal heat riser to precondition the fuel before it gets to the cylinders. The heat comes directly from the two center exhaust ports on each side of the engine. The volatility of modern fuels has brought the need for that robust heat riser into question, as it may cause more problems than it solves. If it does cause you problems, I’d suggest the following: Remove the manifold, revealing the penny sized holes centered on either side of the block. Obtain two wheatstalk pennies (these for the exact metal content), drilled with 1/4” holes, and tap these drilled pennies into the two heat riser holes to serve as a restriction to the excessive heat generated at the source. Your engine will suffer no ill effects from this slight modification, and may prove beneficial during the hot months. Alan
|
|
| 40 Coupe | -- 08-14-2021 @ 8:53 AM |
|
Exhaust gases circulate under the carb. inside the intake manifold, to keep and quickly warm the carb. Poor location to test engine temperature. There is no coolant passing through the intake.
|
|
| flatcreeker | -- 08-14-2021 @ 9:04 AM |
|
I had read about and forgotten about that passage and its' purpose. And yes, I doubt the modern fuel needs much preheating in my climate, especially if I take the Merc with me 300 miles south to Savannah for the winter. Not sure I'm ready to pull the intake but whenever that should occur, I'll apply your modification. Thanks for your knowledgeable counsel.
|
|
| flatcreeker | -- 08-14-2021 @ 9:12 AM |
|
My taking temp reading on heads is my general go-to for understanding the relationship of coolant temp to engine temp. Shooting the intake and carb temp was for general curiosity. Better to know than not know. I'll be temp reading other areas as well. And, now I know that exhaust passage is working. That engine compartment is a regular oven. Thanks for you counsel.
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=16&Topic=15061 |