Smoke coming out of road draft tube-HELP

first thing to do is a compression test. Do a dry and then a wet, if there is a significent difference, it indicates worn rings. With worn rings part of the compression your pistons tries to build slips past partially pressurizing the crank case. when the crank case gets pressurized it pushes the vapor out the draft tube (Which is why if its bad enough it does't depend on vehicle movement to vent.)

If thats the case, then you need to address the ring situation to permanently effect a change.

The other things that contributes to the situation is a lot of short trips, or not getting the engine up to temp through an incorrect thermostat. If you engine is running cooler than spec it will build up condensation and that also will pump out of the draft tube if and when you get som temp built.

 

You didn't say if the engine was sitting very long before you got it.



This low mileage engine sat for almost 20 years before I got it running again. The rings must have been gummed up. It smoked like a train when I first started to drive it. I used "Marvell Mystery oil" in it and it took several heat cycles and runs until it subsided. For a week or two it was a real mosquito killer. There is no mechanic in a can but some of the additives can free up gummed up rings...It did in my case.

I did add a PCV valve but that was after I was sure I wasn't hiding a big problem.




Here it is today.

 

Junk the engine and drop in a Chevy motor.

 

Thats pretty impressive! and yeah my engine sat for 38 years in the car in my grandmothers garage.

 

Put some MMO in it or Rizlone. We had a Pontiac that sat for about a year and ran like **** until the Rizlone freed up the gummed up lifters. It's not instantaneous. It took several trips to free up the gummy rings. The engine was saved because it ran good and the body was a rust bucket. If it's been sitting for all those years it will take some exercise for it to work. Give it some time before you throw a lot of money at it. Regular exercise is not only good for people. I was scared at first but I had nothing to lose and eventually it worked.

It's not a mechanic in the can but at this point you aren't sure you need a mechanic but possibly just a good de-gumming. It won't restore a worn out engine but it could extend the useful life of one.

 

It seems to me that running the draft tube g***es directly into the air intake would mean that air filter changes would need to be done quite frequently. I'm not sure how that would work with an oil bath style air filter?

 

I like that...

 

The only time the the aircleaner gets any vapors on a properly installed PCV system is the rare occasion of the over powering of the system with vapors under a very heavy load. It is not normal for the aircleaner to take in those vapors. Do a search on a "closed PCV system" on Google or be prepared to do a lot of reading if you do a search on the HAMB. Study the system and you will understand.

PS none of my PCV systems tie into the aircleaner at all. I'm not a tree hugger...I'm an engine hugger.

 

I worked on a car once that had a tube running into the air cleaner to burn the smoke.
When I took the tube out the moter would stall!

Now that was buring oil! (also helps on gas milage!) (;-)

 

The coolest thing about my old Flathead was the smoke that would come out of the breather tube after I parked it. It was basically an unspoken warning to Enviro-Nazi's and soccer mom's to steer clear.

 

I vote for this answer

 

here is the 40s solution for worn flathead with smoke.

I wholeheartedly agree for a continually in use engine a comp. test will tell you a lot. If it has been sitting for a long time the compression test may not reflect the true condition of the engine. If the rings are gummed up give them a chance to free up and seal again. I was sure my engine was toast but with some exercise and some Marvel Mystery oil it does not smoke any more and oil usage is not a problem. I never did a compression test before or after but I'm sure it would read differently today.

 

I have a freshly rebuilt 215 in my 53 pick-up and it has a little blow-by as you describe. A mechanic told me to stuff a shredded brillo pad up the tube and that would stop most of it. I thought I would just it let go, as I only see it when the hood is up and the engine is running and that is not very often.

 

just pull next to one of those tree huggers in their prius....then laugh like hell at their raised eyebrows when they see your smoke !!!....I'd just ignore it....after all, it's old enough to be smoking !!!.....hahaha!