'36 21 Stud Smoking from Oil Breather

[keeeef]

Hi

My recently imported '36 pickup is smoking from the oil breather/filler cap? No smoke from exhaust and no nasty noises.

This was a barn find and had not been run for many years. I have only put around a 100 miles since I have owned it.

What should I check first? I have used Penrite Shelsey 30 Light engine Oil suited to vintage and classic cars originally designed to use straight 30 weight oil, is that ok?

Any advice much appreciated, this is my first flathead so learning all the time!


Thanks

[rheltzel]

Check the road draft tube on front of block...it's probably clogged, forcing the smoke out the filler tube.

[keeeef]

Thanks rheltzel, I will check it out tomorrow

[Tom Walker]

Keef
I'd think heavy breathing in a flathead is most likely due to blow by past the rings. It's not going to do any harm but could be a sign of worn rings/pistons/bores. If they get really bad you could get blue smoke out the back and high oil consumption. You could try a compression test. There are threads on here giving figures but I think you should get over 100psi at cranking speed.
If you get alot of fumes in car, you could try routing the breather to the air cleaner.
cheers Tom.

[KiWinUS]

I would put 15/w40 Shell Rotella oil in it & just drive ... HARD!
It may just need driving after sitting for so long .
some Marvel mystery oil in the gas would also be a plus!
cheers
Tony

[Mike in AZ]

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any smoke coming from triangle shaped opening in right front of bottom of engine?....where any fumes should be be coming from the engine, normally....if original 21 stud engine...Mike

[supereal]

Usually, on "Barn find" vehicles, the piston rings are stuck and no longer have the ability to control oil or compression. Using various additives may help, but probably not much. Using a high detergent oil, such as Rotella, which is a diesel engine oil, may loosen deposits creating more problems. Many of these vehicles were driven until they had lots of problems, then parked. Unless you really want to restore it, including engine work, it would be a better choice to sell it to someone who will.

[Walt Dupont--Me.]

The road draft breather is on the right front of the oil pan, you have to be going down the road so the wind will suck the fumes out, when you idle the fumes will come out of the oil fill breather, I would use 15-40 oil, dump some marvel mystery Oil down the carb with it running and flood it out till it stalls, let it set over night, it might free up some stuck rings, Put a pint of MMO in the gas tank, if those early engines have 90# compression that's good. If non of those thing help it's probably got worn rings. Walt

[Blownflatheaddeuce]

In my 37 21 stud, I fitted a PCV under the intake, blocked of the front draft breather on the pan, no more fumes.

Ring seal is fine, cyl psi is even and good.

After I did this mod I stopped getting fumigated and the car runs very clean.

[keeeef]

Located the road draft breather and cleaned it out. Just appears to be one vertical slot facing rearwards. I poked a length of welding wire up inside but didn't go far, is there mesh or further holes? I flooded it with WD40 and will take for a long run later.

Shell Rotella is not available in the UK neither is MMO but will try and find an equivalent.

Will look into fitting a PCV too if it still smokes, are they available as a kit?

Thanks

[bbrocksr]

Check to see if the baffle tube under the fuel pump stand is in place. They get left out and it will smoke like crazy out of the oil filler cap. That was my problem.
I installed the baffle tube and no smoke at all from the filler cap. The baffle tube is part of the ventilation system and it doesn't work without it.
Bill

[keeeef]

Hi Bill

That could be it! Fuel pump stand had a blanking plate fitted when I bought the truck and was running an electric pump but I have changed it back to mechanical. What does the baffle look like?

Keith

[bbrocksr]

It is a round tube about 2 1/2" in diameter and about 5 1/2 long with staggered baffles on the inside. The baffles are cutaway in the center for the fuel pump pushrod and the small tube that surrounds the pushrod. The baffle tube has a flange on the top that fits in a recess in the manifold and the bottom of the tube fits into the block and thus seals the smoke in the valve chamber from coming out of the oil filler.
Without this tube in place the crankcase ventilation system will not work as designed.
There is a long baffle tube and a short baffle tube to fit to fit the different manifolds. If yours is a 36 with an aluminum manifold it takes the short one.
Hope this helps, Bill

[keeeef]

Thanks Bill, much appreciated. I don't recall seeing any baffles when I removed the stand to fit the push rod and pump. When I get home from work I will take it off and post some pictures of what is there and hopefully what isn't.

[keeeef]

No baffles under the fuel pump stand!! Ordered a set today so hopefully will improve smoke and fumes in cab!

[keeeef]

Latest update, tracked down a set of baffles and a bottle of Marvel Mystery oil here in the UK! Planning on putting a couple of hundred miles on the clock over the next few weeks and will see if smoke improves.

In the meantime I came up with a plan (see pics below) to distribute the smoke outside and away from the cab but before I road test it can anyone say whether it would cause a problem.

[green50]

Good thinkin', I like it!

[Ed Pitts]

This is what I hope you ordered. Ed

[keeeef]

Hi Ed, yes that's the same. Smoke has improved already. The extended tube is just a temporary fix and if it's still smoking after a few hundred miles use will strip it down over the coming winter.