I bought this car off of here last weekend and I'm a newbie to the flathead. This car has been driven very little over the last few years (mainly not driven at all from my understanding). Right off on the first drive down the highway, smoke and fumes filled the cabin. Initial thought was an exhaust leak but after further inspection, it appears to be the road draft tube. Again, pleading ignorance, I'm 99% sure this isn't a factory setup but can't find a picture of what this would look like from the factory as it seems most have modified this in their own way. The tube has a visible leak right in front of the firewall and there are a few holes in the firewall which would explain the cabin smoke issue. This tube runs under the car and stops about 2/3 of the way back. The car runs smooth, stays cool, and sounds healthy. I plan to get some marvel mystery oil in it in the near future and hopefully over time, the smoke will lighten up a little. I've seen a few posts about pcv valves but they seem to be about the newer flatties. I've seen breather caps and what appears to be just a small air filter on the fill tube, what are your thoughts for a solution? Any pics out there of what the stock setup would have been? I understand that the smoke is the actual problem, not the tube but I'd like to at least drive it a little without breathing some nasty fumes in the short term. Any help would be appreciated. Sent from my SM-G950U using Tapatalk
Josh...can you just patch or replace the flex tube as a temporary fix...at least the cab would get smoked out,....again what is weird to me is that it didnt get cab smoke until I changed the oil the day before you got it........but one things for sure..it looks good in your garage!!
I thought about that, maybe even some sort of tape (header/exhaust etc) and of course closing the holes up in the firewall. Sent from my SM-G950U using The H.A.M.B. mobile app
That was another initial thought but doesn't appear to be the issue. I was under it after driving last night, nothing on the manifold nor the pipe. There is plenty of smoke exiting the draft tube and is worse upon acceleration, same with the cabin smoke. It increases as acceleration increases. Sent from my SM-G950U using Tapatalk
I thought the rear of the engine is the crankcase air breather (intake of make up air) & the drawing out of crankcase air was done at the front right side of the oil pan.
This was my first thought as I did spill a small amount filling the oil..but it should have burned off by now
That's correct. The oil fill tube in the rear also serves as the intake for air into the engine. That's an old aftermarket tube that was added to take care of the very problem you have. Repair the tube and keep adding marvel to your oil and gas. Hopefully driving this car will lessen its blow by. Adding a PVC would also alleviate this smoke into your cabin. Close up all your firewall entrances.
There should just be a breather cap on the fuel pump stand. Don't know why that hose is there. That is the crankcase breather. On front right bottom of the oil pan is the road draft pickup. The system will not work properly if some one pulled the breather tube out that gos in before you bolt the fuel pump stand down. I would pop off the fuel pump stand and look and see if the breather is in the block.
So I guess I'm not even calling it the right name? Well crap, if I'm not saying something dumb, I'm probably not talking. I'll try sealing up the tube and the firewall and leave it alone.
^^^^^^ Do not merely seal up the flex tube. It should be replaced with a breather. (Or an old rag tied on top of the opening after the flex tube is removed)
Yes sorry you are correct Fritz. I meant to say seal up the holes and leaks at the seals and leave the end open. Never even thought it could be taken literally.
I think was misinterpreted. I'm not clogging the vent tube, just wrapping/sealing the area that appears to have the leak by the firewall.
Josh...when you get home take a good pic of the area so everyone can see it...that tube has a top that slides open so it can be a breather, but its lacking a filter
Deck chairs, Titanic... Never mind the hardware, you seem to have massive blow-by in your engine! If there's large amounts of smoke exiting the entrance your engine is working as a smoke generator and nothing having to do with proper operation of the ventilation system will control it! Lots of possible causes, including things requiring complete overhaul, but start with the hope problem might be fixable. Apparently not run for a long time...can you find out if it smoked badly before that?? It might have been parked because of smoke...or smoke my be a result of petrified oil and sludge from the long dirt nap. If it runs reasonably well, put in TOO MUCH Marvel Mystery oil or other engine flushers both in gas tank and fuel tank and drive it for a while. Drain engine and see what comes out, repeat. General hope is that rings are glued down by petrified filth and that the fierce solvents will start loosening them. If run time with solvents does not seem to start improving things, again, do not worry about the vent hardware yet, tear that engine apart. If you are luck maybe it will need only cleaning and a hone and new rings. If worse...get to work.
I think you should replace your fuel pump stand assembly with the proper one. What I see is a cobbled up fuel pump stand that someone has tried to fabricate into a breather and has done a very poor job in doing so. It looks like electrical conduit welded on to the side of the stand and what could be the lid from a pepper grinder(held in place by a screw), that serves as a cover for the oil fill. The correct fuel pump stand has a top with an integrated breather that allows the engine to have the proper air flow.
Replace the fuel pump stand with the correct part, with the correct breather cap. Here's what's happening with your current setup. When you drive down the road, the air passing the opening of that goofy "draft tube " is acting like a venturi and trying to pull air (which will be from your crankcase) from the opening of the tube. This will obviously pull fumes from the engine......if that Rube Goldberg tube and mount have any openings, the fumes will exit there. The factory system worked like this: outside air ENTERS the engine through the breather cap, travels down through the crankcase, and exits through the little triangular opening at the front of the oil pan. This air movement happens while the car is moving forward. So the venturi effect occurs by the air passing over the opening in the oil pan. Where this simple design breaks down is general wear is the cylinders (pistons, rings, and the bores). Gradually, the crankcase becomes a bit pressurized by the bad fit in the cylinders, and more engine oil is burned. The blue smoke is going to get blown out both breather openings, as well as out the exhaust pipe. No one wants to have the blow by all over their firewall, so you're seeing a contraption made to try to reduce this. Marvel Mystery oil treatments may help with the piston ring sealing. A few treatments and some mileage will tell. After that you'll want to do a proper compression test to see if this motor needs immediate attention. For now, I'd get the factory breather stand and breather cap back in place. You may also have to check the opening in the oil pan to make sure it's not clogged. Last but not least, I'd stay with 4 to 4.5 quarts of motor oil when there is no oil filter. More than that may be too much, aggravating the problem.
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