hi ya'll, working on my 51 vicky, 1950 8BA, stock, with the ford 54 carb. i have gas in my oil after only driving the car for a short distance and i have tried to fix it by rebuilding the carb, rebuilding the fuel pump, and installing a fuel pressure gauge set to 2. i changed the oil, drove it for about 20 miles and still gas in the oil. any suggestions? thanks!
Curious how it runs With the engine running, place your hand over the breather/oil fill, rev the engine should feel a suction, if you feel pressure I would do a compression test
^^^^ that and did you use the correct power valve? Some have an incorrect sealing surface. Daytona Carburetors have the correct style, as does Vintage Speed.
Yeah, gotta think simple. Gas in the rear tank can only get into the engine 2 ways, fuel feed and distribution. Most likely is the carb. You can run a test electrical pump and bypass the mechanical pump to confirm, but the focus should be the carB. Are the plugs showing rich?
hey ya'll, yes, i should have included more info. the engine is a fresh build. compression is 120 wet across all cylinders, 100 plus dry. it runs great, no smoke plugs do smell of fuel when pulled. as for the power valve, i replaced it when i rebuilt the carb but i can't recall what size it was. what size should i be running? thanks for the replies!
i've changed the oil after trying each of the 3 fixes, rebuilt carb, rebuilt fuel pump, and adding a pressure regulator, and after only 15-20 miles, the oil is black, thin, and smells of gas.
I put a regulator and gauge on my ‘42 221, because I had an electric pump, the stock one was shot. I used a 0-5 gauge. Set it at 1.5. Still too much fuel. Plugged the gauge hole, lowered the pressure until it was good. No clue what actual pressure was, it worked for me.
Stock fuel pump on the back of the 8BA? I know you rebuilt it but... And take a sample of oil and send it in to be analyzed. You can learn a lot that way.
You posted that you installed a fuel regulator. Is it a "deadhead" type or a bypass type. I have posted many times, but again won't hurt: The inline dial-type regulators with no bypass are quite useful if you have a strong right (or left) arm, and a rabbit problem is your garden. Have you at least temporarity installed an actual pressure gauge at the carburetor to read the true pressure?'' For a regulator to really work well, a bypass style regulator with an external fuel return line should be used. Jon
So, I'm going out into left field. If you are changing your oil, "fixing a fuel leak into the motor (either by repairing the carb or the mechanical fuel pump)" then driving the car 15 or 20 miles, then doing the sniff test on the oil, is it possible you are not getting the motor warm enough to "burn off" the excess fuel that may be coating the inside of the motor? How much fuel is actually mix with the oil, just a hint of smell, or is it a nose burning potent aroma? If you have fresh oil, and a new oil filter in place, and the gas smell doesn't knock your socks off in 20 miles, I believe the motor needs to run longer to remove all the gas smell. Obviously, if the gas smell is very strong after a few miles, then the extra running time may not be advisable, but with just a hint of smell, I believe it needs a longer running time. The process of "burning off the gas smell" doesn't start until the motor reaches operating temp, then it needs to run at least another 1/2 hour after that, an extra 1/2 hour longer probably wouldn't hurt. If you really don't trust the fuel problem has been fixed, then you probably need to do back to back oil changes. If indeed the motor has a gas film inside of it, as soon as you added the new oil, it became contaminated and will smell like gas shortly after the fresh oil has circulated through the motor, regardless of weather or not more fuel has been added to the oil or not. If that motor was cold when you started on the 15-20 mile drive, probably 1/2 that time, the choke was partly closed adding excise fuel to the system. Until the motor has been fully reached operating temp, then ran for more then a half hour, and maybe for a full hour, the oil is going to smell liker gas.
Try removing the carb and putting it gently in a vice. Get a container that you can set on a stand or stool or suspend above the carb. Put a cut off valve in the fuel line from the container to the carb. See if the carb leaks or overflows with just gravity providing the pressure. That way you may not have to change oil again. If you have the correct pressure going to the carb, it would seem that the carb has to have some issue.
ok thanks for all the suggestions. when i pull the dipstick, the oil looks fine but when i drain it, it is black, thin and while it won't make my eyes water, it smells of gas. i'll try running it a bit longer and see what happens. i'm a bit gun shy about running it too long because i'm worried that the gas is washing the cylinders clean and i don't want to damage the engine. the regulator is not a return type. it's a round dial type and to be honest, it was a el cheapo special. carbking, can you recommend a good bypass one?
My experience with most non-return regulators is if they can't return the unneeded fuel to the tank, they don't regulate the pressure very well. There is no way to relieve the pressure so it keeps building. They start out OK, but the longer they run, the more the pressure builds anyway. You need a return line for the regulator to function at its best. That could be your entire problem. Please get a return line on it before you drive it again.
If the rings aren't seated yet, there will be a bunch of blow-by so CSPIDY's statement won't hold true. If you're not seeing a visual leak down the carb throat while idling (heavy dripping), I'd dare say look at ignition. As they say, most fuel-rich carb problems are ignition and the stock 8BA distributor has no centrifugal advance. A rich fuel delivery combined with weak or improper timed spark will result in extra fuel in the cylinders that can get past the rings. I run my 8BA at 16 BTDC at idle and it burns CLEAN. If its set up too rich it won't want to start easily after the engine warms up. It'll run warmer than stat temp if its too lean or doesn't have enough timing advance.
I don't know about a return fuel line , lots of flat head guys hear running without one very successfully. Sorry I can not be of more help.
I haven't purchased one in 25 years, so no, I cannot recommend a current one, as I don't know what may have become available. Holley used to be the "go to" brand. But before you buy one, get a fuel pressure gauge and TEST the actual pressure! If you need the regulator with the bypass, you will need the gauge to adjust anyway, so the purchase will not be wasted! Jon
Test the carburetor for leakage. It’s very simple. You need a bucket and paper towels. Crank and run the car briefly. Run it enough to fill the bowls. Place paper towels in the bottom of a bucket on the garage floor. Remove the carburetor. Be careful with it. Keep it level. Wipe off excess gas Place in the bucket on the layers of paper towels. Put a lid or towel over the bucket Check it in a few hours If the towels are soaked, you have a leaking carburetor, likely from the power valve.
I suspect the power valve too. The PV needs to be flat across the surface of the valve and the carb bowl aftermarket/modern ones can have a radius and the valve won't seal and leaks fuel past it Charlie Price has the correct/machined flat ones.... Good luck
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