Smoothest 4 Cylinder Flathead Ever
 

I'm making progress. I got the 8BA in my "new" truck freed up and it's running pretty decent. Only problem is it's running on four cylinders (2,3,5, and 8 only). I imagine one of the carb jets (the left one I think) is clogged (those type of things happen when one gets parked in a barn for 20 years). It absolutely amazes me that my "half" engine is running so smoothly. I'm getting great fire in the other four cylinders. Just no detonation. Now if I could just get the carb off so it can be cleaned and rebuilt. I unhooked everything last night and it won't budge. Original carb on a motor that has never been rebuilt or torn down. Any suggestions?

You took the nuts off all THREE mounting studs, right?? Some people forget about the last one!! Otherwise, it could be a really sticky gasket. Some light persuasion with a hammer on the cast iron base could help.

Yeah a little light persuasion with a rubber hammer did the trick. That gasket was stuck on there tight. I'll admit that I almost didn't notice that third nut, and I can easily see how somebody would miss it. Pretty much pure varnish inside. I took my time tonight and cleaned that carb thoroughly from top to bottom and put all new gaskets in it. It helped a ton.

Glad to hear. :-X22 Whilst it's apart, put a little fuel down the acc. pump well, assemble the AC, but leave the top off. With your hand, give the throttle lever a couple of twists to make sure gas is squirting out of both barrels of the discharge nozzle. They will be small streams.

Just make sure the accel pump discharge check valve (looks like a float needle) doesn't blow out! Stick your thumb over it.

Thanks. Will do. Right off hand, can you guys tell me the firing sequence? I tried to find it in the shop manual. But I'll admit that I was a little delirious and tired when I was looking.

Okay. The carb rebuild/cleaning has been a success. The truck is running a lot smoother. BUT this "four cylinder" thing is driving me nuts. My dad has a 50 ford car with the same motor (8BA). I snuck over to it and pulled plugs number 1,4,6 and 7 and the dang thing started up with just a hint of a miss at idle speed. So now I'm thinking I'm not as bad off as I thought I was. I don't claim to be anything close to a mechanic, and I'm definitely not the sharpest knife in the drawer when it comes to these type of things. I'm just trying to learn and do this right. I set out to prove to myself that the other four were not hitting. So I took off down the driveway with all four plug wires off. That didn't work out so well and the truck quickly died. So I've convinced myself that this is "normal", and somehow these cylinders are hitting at higher rpms or whatever. Can somebody PLEASE explain to me HOW this flathead can literally idle and run pretty smoothly with all four of these plug wires off and is this thing right? I know I am not the first person to discover this because I have read about this same thing on another forum.

I've never heard of it. 1-4-6-7 are on one barrel of the carb (driver's side), the rest are on the other. Your idle circuit on the one side must be plugged up still.

I tried sticking my finger over the #1 plug hole and checking the timing with the rotor button. But I honestly don't feel any compression buildup. I feel suction and that's it. I'm gonna check the compression tonight and go from there. The top of that intake looked good when I had the carb off. I just cannot understand it. Here's what I do know. With the 1,4,6 and 7 plugs completely off, the motor will start and idle decently. If you try to drive it that way, it fouls out pretty quickly and quits. So something is happening I imagine in those cylinders. Any further suggestions will be highly appreciated.

Do keep in mind that Schramm built a kit that would turn a V8 or even a Model A four banger into a compress that utiliized special heads that turned half the cylinders into compressors. I say this to illustrate the point that these engines will run on half the cylinders.

Has this engine been sitting? You could have some valves hanging open or stuck rings (lack of compression). With the engine running, dribble some Marvel Mystery Oil down each venturi of the carb. It will smoke like the devil, but it may help unstick the valves, if that's the problem. Do try a compression check regardless. The MMO trick should be done.

I will definitely do that and let you know. Yes indeed the engine was sitting for almost 20 years. It took me about 6 days of pouring marvel mystery oil down the plug holes to get it freed up. I think the dipstick was showing something like 4 or 5 extra quarts by the time it freed up. I changed the oil and filter and had it running within 2 hours of that. The amazing thing right now is it doesn't smoke at all even on startup, but it has lost some compression SINCE then (i.e. I was able to park it on an incline intially after I got it running, but now it backs off). But I will definitely do that trick with the MMO. That is some good stuff. I will keep you updated. Thanks so much for the advice.

It's really easy to pull the intake manifold off to check for stuck/sticky valves, and you can then hit the stems directly with MMO (or better yet SeaFoam), both in the valve chest and thru the ports. Mine had sticky, varnished lifters.

If it sat for 20 years, then I would almost guarantee that there are some valves stuck open. These flatties were really bad about sticking valves if you left them sit for too long. You're just speculating and guessing right now, though. Run a compression test. That will tell the story. If you have a couple dead cylinders with no compression, then peek down the spark plug holes of those cylinders while you turn the engine. You can see the heads of both valves through there. Spray the stems of any stuck valves with laquer thinner and then work them back closed with a screwdriver through the plug hole. It will probably take a few open/lacquer thinner/tap back closed cycles to get them moving on their own again. Once they do, give the stem a squirt of Marvel Mystery Oil before you fire it back up.

Thanks so much to all of you. I'll definitely get on that this evening. Lots of great advice that I really appreciate. That compression test will tell the tale. I'll keep you all updated.

Okay here's an update. I did the compression test. #1 cylinder has no compression. The valve on the left above the #1 cylinder is stuck in the open position (i'm assuming that's an intake valve). All the rest of the cylinders had a pressure of about 85 to 105. And all of the other valves move freely when I look right at them. As luck would have it, that stuck valve in #1 is very hard to get to. I can't even see the valve head itself. Just the seat. I sprayed some PB blaster in there and I could see it gurgling around down below the valve seat itself. A skinny screwdriver won't hardly even get on top of that valve. I bent a piece of stiff wire and was able to get on top of it, but obviously that isn't gonna move it. I squirted some oil down on top of that valve stem as well. We'll see if that frees it. If anybody has any suggestions on a homeade tool stiff enough that's safe enough to get on top of that valve and gently push it back and forth, I'd be appreciative. To be honest, I figured I'd find more than that one single stuck valve. Man I hate to have to pull the head for one valve, but I imagine that's coming.