Yesterday I got the flathead started in my '46 for the first time: WOHOO!!! It ran smooth and nice until the ignition coil gave up. The coil resistor was toasted, and the previous owner had made a bypass connection instead of fixing it... For once I got lucky and found a new coil at an off-roaders' bizarre shop, and got it running again today. Anyway, I checked the oil and saw that the level was way above the Full line, and it felt thin and smelled of gasoline. I emptied the engine and filled it up with new oil. Started the motor and ran it for a minute or two, and again I got the impression that the oil level had risen and smelled lightly of gas. What can have happened? While I'm at it, can the stock-type closed distributor cap be traded for a crab-style cap? The crabby one seems to be more convenient to use but just want to make sure it won't interfere with anything. Thankful for any help/suggestions/advice. Working with flatheads is a new thing for me, but I really like that li'l motor and want to learn as much as ever possible about it. Chris
I'd bet on a failed fuel pump diaphragm; If you like the way the car runs, it's unlikely the car is running rich enough to do that! There are several carb problems that could dump lots of gas in there, but car would run badly or not at all. For open distrib, you need '42 cap, rotor, and clips. Clips are available and cheap from all the restoration places, the rest can also be had through big USA parts companies NAPA and Standard. I kind of prefer the closed because that location is so exposed to water in a storm.
Some people used to add an electric pump in line between the tank and the stock pump to prime the carb after long naps and supposed to be a cure for "vapor lock". If the stock fuel pump diaphram develops a leak, the electric pump can pump the crankcase full of fuel and you will never see it. If you have an electric "booster pump" underneath, check the stock fuel pump diaphram. obviously if you don't have the extra pump then it's got to be a carb problem.
I've seen it happen a few times, The float in the carb is being lifted at the needle valve and allowing fuel to trickle passed and run down the intake into the engine. Also, Make sure that it isn't water, you may have a cracked cylinder wall or blown head gasket.
I've been under the car quite a bit, but not seen an extra fuel pump. I'll check the fuel pump diaphragm anyway, just in case. alittle1, can you explain that to me again, please? I didn't understand it completely. The carburetor was wet around the base, but as the motor ran quite well I didn't suspect that the carb could be the problem. If it makes any difference, I just started it in the garage and didn't take it for a test drive. It's still brakeless and on jack-stands, so a proper test of the engine will have to wait a little longer. Thanks for all the help, guys!
Bruce, I guess you're right, I just wanted to make things a bit easier to maintain. Whenever I need something I have to spend far too much time finding the parts, by phone or searching the internet. With the '42 cap I would at least be able to get spark plug wires at the parts store around the block.
Actually I've always heard the 46-48 cap is more prone to trouble and moisture than the simpler crab cap? FWIW I put the crab cap and rotor on my '47. I got clips from the junkyard. I don't know what they are even from, I just looked for cars with short clips and I took a few pairs home. Fuel pump diaphram is the most likely cause of fuel in the oil.
Good suggestions, but also run a compression test if you have not done so. Myself and others I know have had flathead engines that basically idled and ran fine with only 7 good cylinders. In one motor's case there was a hole in a piston and the engine still basically ran fine. Mike
Hey Guys, Only one crappy cylinder? I drove my 8BA for over two years and when I got around to doing a comp test I got an average of 60PSI (100PSI is the norm) and 20PSI on one cylinder LOL. Some times you cant kill this motors with a stick... Danny
Let me reword that. 7 cylinders with below 90 psi, and one at 0. Still sounded fine at idle and ran on the freeway. There was a lot of blow by though.
Hey mate, I guess mine was the sports model for that year with a 20psi head start on my number 4 cylinder lol. Danny
My '40 Chrysler Flat-six had gas in the oil. After a bit longer the fuel pump crapped out and the diaphram was shot. Check out your fuel pump first. Carb problems also could be it, but if you crank over an engine a bunch of times, pump the gas or prime the carb and it doesn't start right away, that'll make your oil gassey as well. Just a thought.
If the compression is low enough the rings will allow the fuel to be forced past them when under compression. I has 75 thru 90 lbs in the old flatty and it fired right up and ran real stong but I kept getting gas in the oil. I did not have an electric pump hooked up nor was the stock pump. I was running it via a gravity feed fuel system and the carbs were rebuilt and bench tested. The bottom line was worn rings and what were not worn were stuck from sitting so long. Pull the head with the worst compression and fill the cylinders with gas, then check it to see if it runs through the rings to the pan.
Damn, all this talk about holes in the pistons made me nervous! As Thriftmaster said, the car sat for quite a long time before I got it so stuck rings may be a possibility. I'll run a compression check to make sure.
With all the CRAP they put in gas now you can't turn you back on it!!!!! The diaphram will be cracked and hard or both plus your rings are probably stuck and your carb is also chalky and leaking gas down into the cylinders Don't take off the heads yet!!!! Remember.... If it ain't broke don't fix it!!!! NEW Gas SUCKS!!!!!!!!!
A compression check is easy enough to do, but my money is on a bad fuel pump diaphragm. You're getting too much fuel in the oil too quickly for it to be the carb IMHO - if that much was running through the carb, I seriously doubt it would run. Blown piston is a possibility, but if it was running fine when it went to sit, it should be OK. Stuck float is possible, but unlikely because you'd probably have fuel everywhere AND it wouldn't run right (unless you have an electric that's running when the engine isn't). After you changed the oil the second time & it smelled "slightly" of gas - have you run it again since? There may have been some residual fuel-contaminated oil - enough so you could smell it anyway. Maybe another quick oil change might be in order?
Fuel pump.Had a flathead with a dime size hole in the piston ,smoked like hell and burnt a quart of oil every 50 miles.Sometimes it would backfire when starting it and blow the dipstick out and oil cap off.A small hole in the fuel pump will put a lot of gas into the oil.
I agree with the fuelpump check. But have you checked the sparkplugs, i had the wrong type and the exhaust valve hit the electrode closing the gap completely on 3 cylinders.. Resulting in Gas in the oil.... Some other reason causing it not to run on all cylinders can cause this to, of course...
I checked the fuel pump, and the membrane looked fine. Also, I saw there are four small holes in the pump under the membrane. If it would leak gas thru the fuel pump I guess there would be some gas trickling down on to the manifold that way as well? Next step was to check the plugs, which were new before I started it. They are all sooty from combustion so hopefully that means that it's firing on all cylinders. I hope that means there are no holes in the pistons. However, as soon as I turned the motor off it started to trickle gas from somewhere around the base of the carb. It must be a carb problem after all then, maybe together with leaky rings? I'll run a compression test when I get hold of a tester so we'll see what comes out of that. Lars, so what will your nickname be when you've sold the '42?
OK, Carb time... That trickle and the soot suggest bad power valve draining the carb--it has a small diaphragm that can split. Other possibles, kinda in order... Sticky inlet valve from long storage level set too high--put it at LOWEST flot level of published specs fuel pump pressure too high--not very likely here. If dribble is from one of the several things that can overfill float chamber, when you look down top you will see the fuel syphning out via the nozzle bars that cross each tube near the top. If bad power valve, leak will be way down at bottom of carb, probably not visible from top. Also, look down carb while idling--does there seem to be lots of dripping from those nozzles while running?
Also, once you defeat your fuel leak... Since car has been sitting, run a solvent type additive in oil and gas to free up petrified grud in your system--we'd use Marvel Mystery Oil. a patent medicine from the 1920's, over here... STRONGLY consider having gas tank boiled out--you have some problems waiting in there! Consider an extra filter that's easy to clean on fuel line. Definitely disassemble and clean carb. And, if it's a happy runner, don't take apart anything that doesn't need it!
Lots of good advice, thanks! I checked the compression and it was ranging from a low 65 psi up to 80-90 for the four best cylinders. Could be better, I guess. Bruce, I am not completely sure what to look for but I started it, let it idle and it looked like there was a steady trickle from the nozzles. I'll pull the carb and give it an overhaul, then we'll see how things go.
That sounds like very high fuel level--probably dirt in needle valve, sunk float, or such--gasoline often forms varnish or glue when left alone for a long time. Those nozzles are the main discharge when engine is running fast enough to activate the venturis. At idle, there should be nothing happening there.
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