Fhead Tuning Issues

did some work on the 3B the last couple weeks, So during the NH run, my two biggest problems (other then fire ), were the engine running too hot, and some carb issues that kept creeping up, mostly centered around restarting and low idle stalling. I was running the stock radiator, but with a smallish electric fan, and no shroud. I also found out i had a bad thermostat, which probably caused most of my cooling problems.

But in all the willys runs i have gone on, i have only seen cooling problems with systems that were modified. Like different radiators, electric fans, no shrouds etc. Since i had an original shroud and fan, i figured i would put it back to stock, replace all the hoses, (don't know how old they were) and install new thermostat and see how that goes. In my limited testing, its cooling much better, and more consistent now. My carb issues, im thinking are a dirty carb, mine is a pretty fresh rebuild, but i had some line, filter and tank issues after i installed it and the carb might have got some crap in it, so i had Rick P build me a new one, along with the carb, somewhere along the line, the stock air filter was removed, and replaced with a halfassed K&N installation. Again, seeing the stock setup usually working better, i put it back on, but i did modify it to use a bigger, and better installed K&N element inside the stock housing.

also After the run, my two small leaks were much bigger...LOL, the Tcase i have to work on still, but im thinking its the front output seal. The oil pan/timing cover was leaking too, i pulled them, flattened the flange, and put new gaskets on, leak is gone now, also was able to confirm the timing gears were correctly lined up, so it really leads me to believe my running issues are the carb.

 

I like the vacuum gauge.

 

While addressing your cooling issues, you may want to replace your fan belt. The belt in your photo is to narrow for use with the water pump pulley. Normal engagement between the belt and pulley is from the sides of the belt and not off the bottom of the belt. With the load the belt will see from the fan/water pump and alternator, I believe it will start slipping soon if it isn't already.

 

Yes, totaly agree, i have a new alternator with wide pulley going on soon with the correct belt. I will confirm, with that belt and pulley on there now, i can not get it tight enough to not slip

 

Running much better now, not sure what was the actual problem, But for the final fixes I put on a fresh carb, and the stock air cleaner housing but with large K&N filter in it and all stock housing connections. Also put the stock fan and shroud back on in place of the electric fan. Also redid all the battery and ground cables when I wired the welder. Started it up, ran smooth, strong and is pulling a steady 19-20 on the vacuum gauge.

 

It’s also cooling much better. Replaced all hoses, thermostat, flushed everything, and put shroud and stock fan back on. In the video you can actually see the power of the stock fan and shroud pulling the windshield strap in front of the grill

 

I'm a believer that a proper-fitting fan shroud makes a huge difference in cooling efficiency. Yes, the stock fan will pull a lot of air through the radiator when set up correctly. That, and the wonderful iconic sound that is the trademark of the 134's.
-Donny

 

helps drowned out some other noises..

 

Sounds better than my CJ5!

 

So i used today, one of the hottest days we have had this year to test out the cooling system, and happy to report its cooling fine after changing back to the stock fan and shroud. Air temp was 96 and full sun, and it was fine as i was crawling around the neighborhood. It’s also running real good, with vacuum up to 21-22