VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Road Draft tube, how to remove sludge?

I saw this suggestion in another thread but did not want to hijack the focus of that thread. I have a 216 in my 41 MD.

In the thread it was stated, 'road draft tube is not plugged up with sludge. If it is plugged up, pressure will build up forcing oil out all over.'

I do have oil leaking after running only (not counting seepage).
1. How to I check the road draft tube?
2. If it is clogged how do I remove it and clean it?

I know that these are known to leak but my leaks allot after each run.

Well... I know what I'd do, but you may not want to do that.

I'd crawl under the car, wipe the end of the tube as clean as possible, put my mouth against the end of the tube, and blow.

You should be able to push air fairly freely through the tube.


As for cleaning,

I've never had to.

But I know others here have and have a variety of methods that sound good to me.

You should be able to see some fumes coming out of it when engine is hot and running.

To make Stoveblt's suggestion a little more palatable, you could use a clean plastic hose between your mouth and the Road Draft tube.

Just don't inhale. ;-)

Dean

This is what I did with mine for my 51.

I cleaned the road draft tube on my 48 a few months ago and the one on the 34 yesterday. Prior to cleaning, the 48 always dripped after driving the car and stopped after I cleaned it. I clamped the tubes to an old wire milk crate sitting on top of a couple saw horses outdoors. The tubes were oriented in their upright position. I used a propane torch alternating in both the lower openings until I had a good fire coming out the top. They probably burned for 30 minutes or so. I used the torch occasionally to keep them burning until they wouldn’t burn any longer. After they cooled lots of powered ash came out with a little banging and compressed air. I don’t know how this would work on a new style draft tube that does not have the oil fill opening on the top. Mike

I have read about this method before and I think it would produce the best results.

I thought the draft tube had a "mesh filter" in them to reduce the amount of oil passing through them. If that is the case Steve and minetto's idea would damage the mesh if not totally destroy it. I cant think of any other way of clearing it though.
Tony

Had always heard that using fire destroyed the mesh in the draft tube. Dad always soaked the draft tube in kerosene until the kerosene ran clear. I have followed that procedure on my '40 except I don't know where you can find kerosene these days. I have not had to clean the filler draft tube since the new oils and unleaded gas came out. There just isn't any sludge build-up like there used to be. I think I would use brake cleaner if mine were to clog up these days.

If the mesh inside is a wire mesh... I would look for a shop that rebuilds engines, or even just heads, and ask them to dip the draft tube in the "boiling tank" they use for boiling out blocks and heads.

If the mesh is the old "moss" like what was used in air cleaner elements... you are pretty much restricted to soaking in solvents.
I would try lacquer thinner first.
It seems to have been the "go to" solution Chevrolet suggested for really stubborn crud in carburetors etc, and it worked for me.
Buy enough that you can submerge the part with the mesh in it and leave it there for some time.

PS
See Gene's post below this.
Thanks Gene, always wondered, and now I know!

There is no mesh in the road draft tube. Just a round inner baffle with breathing holes in it. t is spaced about 3/8" of an inch from the outter tube. The space between the tube and baffle is what fills up with sludge, When it grts bad enough it can cause a blockage preventing oil from passing through when you add oil.

Here are pictures of the draft tube on a spare 1941 engine. Notice the inner baffle and outer tube mentioned.

Mine has those holes in it when I look down it. I will blow air up it this weekend to check it out.

If you blow air in blow from the top down. Blowing from the bottom up can blow sludge into the engine.

A lot of general leakage today is caused by the 20 or 30 or 40 year old hard cork gaskets.

I put mine in the BQ gas grill. Turn grill on high and put draft tube in. Leave it in for 15-20 minutes and shake out the white powder. Use the grill and you will never taste anything but food you are cooking.

You can find kerosene at Home Depot. Hendo

It might be cheaper to just find a NOS tube as HD gets 16-18 dollars a gallon for K-1 and then after using it needs to be disposed of as hazardous waste.