Anyone know old flathord Ford stuff?

[70 Challenger Lover]

Helping a friend last couple days with his 49 Mercury but I'm a fish out of water with that older technology. Anyone have much experience with flathead v8 engines? I assume all makes of that era are similar in design or no?

[jimynick]

What are you trying to do with it? What's it out of? Here's a link that might help. They're pretty simple, but have their quirks- 3 main bearings and 3 through the block exhaust ports for 4 cylinders.
https://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.diyford.com%2Fwp-content%2Fuploads%2F2016%2F09%2FSA379_Page_093_Image_0001.jpg&imgrefurl=https%3A%2F%2Fwww.diyford.com%2Fassemble-ford-flathead-engine-ultimate-guide%2F&docid=YHYXaCGrBnhRzM&tbnid=lX4yOCQg8gxwaM%3A&vet=10ahUKEwib3aCFxPzkAhWKu54KHZ_4BoQQMwhnKBEwEQ..i&w=250&h=168&bih=977&biw=1858&q=how%20many%20main%20bearings%20in%20a%20flat%20head%20ford%20V8&ved=0ahUKEwib3aCFxPzkAhWKu54KHZ_4BoQQMwhnKBEwEQ&iact=mrc&uact=8

[1 Wild R/T]

Compression, spark and fuel... Don't get no simpler than that....

[73440]

What are you trying to do?
Owned a 51 Ford F1 with a 239 Flathead years ago, have a few manuals and books and some parts.

[70 Challenger Lover]

Thanks for that link. I'll read up on it today. It's a 49 Mercury with a 255? Cubic inch v8. So basically, my friend calls and says he bought the car and it was running fine for months. One day he starts it up and walks away while it warms up. He returned a short time later to find it boiling over bad. The car has electric fans (along with a whole engine bay full of cobbled crap) and the fans failed to turn on. After that, the car starts and idles fine but sputters and dies when you try to drive it. Our plan is to return the cooling to original.

Having zero experience with this design, I looked for signs of a blown head gasket but saw nothing obvious. Most of my time there was simply trying to figure out how this motor differs from later v8s I'm familiar with. It has an aftermarket distributor. I found the initial ignition timing was retarded ten full degrees and reset it to five advanced. The carb idle mixture was a touch lean as well. These little changes made it idle even nicer but didn't fix the main problem. I'm not really sure where to start on this thing. It does idle beautifully and there is no steam or anything like that out the exhaust.

Initially I thought the original 2 barrel carb might have an accelerator pump and maybe that's why it falls on its face when it's under power. After driving it though, I can see that cannot be the sole problem. No matter how gently you take off, it gets up to 10-20 mph then starts coughing and dying. It will restart eventually and just idle. Could this be a fuel pump issue? The original pump is seeping fuel at the top lid and there is also some sort of vacuum line going into the base. What does that vacuum line do?

The fuel pump is some ugly monstrosity on top of the intake. It has a clear bowl going into it and is full of good fuel. There is an aftermarket filter between the pump and carb inlet. Maybe it's clogged? There is also some sort of regulator right before it goes into the carb. It looks ancient so not sure if it's original and not even sure it's a pressure regulator.

My thought is to temporarily run a soft line directly from the fuel pump to the carb inlet and cut out the filter and regulator just as a test. While the line is off, I can use a gauge to measure fuel pump pressure.

Any other thoughts? Am I on the right track?

I guess what I'm most worried about is that some major damage occurred to the block or heads when he overheated it and I'm not sure how to diagnose that.

Thanks

Mike

[Rich G.]

I had a 36 Ford. The only difference is the valves are in the block instead of the heads basically. Still works like a regular engine. Just harder to work on

[1 Wild R/T]

Sounds very much like a fuel issue...   disconnect the line to the carb and test how long it takes to fill a soda bottle, should be less than 15 seconds or so... If it's close look elsewhere but that'll check the fuel lines, tank & pump.. Next open the top of the carb.... Actually no, try this, rev the engine to 2500 or so & close the choke, it'll draw lots of raw gas through the carb flushing everything out.. as the engine loses rpms open the choke and keep the engine running allowing it to clear the raw fuel.... Often once is not enough so dit a few times... If it's better great, if not pull the top of the carb for a visual...

So far I've focused on fuel and it does seem like a fuel problem but it could be ignition so if the carb is clean inside I'd look at the ignition, is it points or electronic?

[70 Challenger Lover]

Thanks, I will try that. The carb is a strange looking thing. Almost like it's upside down. I was hesitant to remove the top for fear I'd expose the bowl and floats and not be able to get a good seal after that. I can try both your tests though easy enough.

After I dialed in initial timing, I checked to see if the dizzy advances internally and it did. I got another 20 degrees and it seemed to be all in by 3000 or so. In fact, in the driveway, getting it to rev up high and hold isn't hard at all. It's only under load that it falls on it's face. In the driveway, you'd never know it had any sort of problem.

Out of curiosity, what is considered max rpm on a motor like this? 5000? Less? And what sort of total advance does it want? Without knowing, I'd guess the same as most other v8s, around 35-36 degrees.