The Stovebolt Site Forums The Shop Area Engine Shop Draft tube leaking oil and comes out of block

So my 1950 chevrolet passenger car leaks oil . I installed a 261 out of a 1958 truck . Converted electrical system to 12 volts . Been driving the car for a few months and noticed a oil leak . I thought it was fuel pump gasket so I replaced it . I found the draft tube on the passenger side of the block coming out of the block so I removed it and put some silicone . Reinstalled it , Few days later same thing . Leaks out of the draft tube and wants to come out . Does this make sense possible worn out motor excessive blow by wrong tube from another year engine not the right one . It does go in pretty easy I'm thinking maybe it's for a 216 . This motor runs pretty strong doesn't appear to have smoke was sitting awhile after t was rebuilt .

How much oil does it leak? Is it a drop or two or a good drip? I thought all draft tube systems leaked a drop or two. A friend of mine has a willys that has a draft tube system and he installed a tuna can to catch his oil drops. Someone can correct me if i am wrong about a few drops oil coming from the draft tube. I saw an old picture of a road where the middle of the road was black from the old trucks and cars leaking there oil. Again from my understanding a few drops is normal but anything more is not normal. Please correct me so i can understand. I am building my first 235 draft tube system and not sure what to expect.

yes Jamie, if a stovebolt isn't dripping oil it must be empty commonly folks keep a drip tray on the garage floor under the engine area
some dripping from the draft tube is common from oil vapors and water condensing, but also there should be some shreddy metal mesh filter material in the can part that can get saturated after 50 years, and flushing it with solvent would be good - some of the old manuals suggest burning them clean, although that will mostly destroy the mesh

Bill

Robert,

What are you referring-to by "Leaks out of the draft tube and wants to come out."

Are you referring to leaks around the base of the road draft tube, where the base of the tube enters the block? Didn't the silicone sealer around the base take care of this?

Or, are you referring to drips out of the draft tube?

If you are referring to drips coming out of the draft tube, how long are you driving your truck (the length of time from cold-engine-starting to stopping/parking the truck and checking the road draft tube)?

As Bill posted, drips out of the road draft tube can be normal, especially if the engine has not been running warm for a while.

Even if you are not taking long trips (and can therefore expect drips) take Bill's advice - check for mesh being there, and then soak the tube in kerosene or diesel fuel (after soaking, you could drain it and use some water-soluble grease remover on the mesh inside the tube).

Are you losing coolant (after letting the coolant-level reaches its normal distance below the top of the tank)?

It leaks a lot of oil more than a few drops its getting all over the underside of the car . I was thinking if the mesh was plugged up maybe that could be the cause of the tube coming out of the block and leaking oil the tube slides in easily ino the block so after driving about 10 miles the tube actually walks its way out of the block . I have to push it in the block again . I used silicone rtv and it still pops out and leaks . I was thinking that maybe it has the wrong draft tube or it's plugged maybe the tube is for a 216 . Oil gets expensive and it's getting really messy

I don't think there's any difference in size of the tubes, but yes, being plugged is likely if it gets pushed out - OTOH, RTV is not a glue, especially as you'd have a real hard time getting the metal surfaces clean enough for it to stick, might be better off using some thin shim stock to tighten it up after you clean it well - it should be a very tight press fit, most folks have a hard time getting them out

but if you've got that much pressure in the pan and are getting that much oil out the road draft, I'd say you've got a blowby problem

Bill

take the tube down to a muffler shop and see if they can expand it a tiny bit? So where is it leaking? around the tube or out the end? And don't use the silicone, you are just going to get globs of it stuck in your oil pump pickup or some other undesirable place.

It's leaking a little bit out of tube opening , but the big leak that's soaking my starter suspension and distributor is oil leak at the block and tube . I just noticed that my steering linkage is really close to the tube being this is a car amd the motor came out of a truck could this be contacting the tube on a sharp lt or rt turn . Im going to verify its not making contact remove the tube and make sure it isn't plugged it's very old and it's possible . When I push tube back into the block it gets really close to suspension linkage . I'll use my exhaust expander and stretch the tube slightly clean block and use some silicone rtv . Retest see what happens

I would caution against using RTV silicone to seal your tube. I'm not sure you can get it clean enough for the silicone to seal good and as brokenhead mentions your going to end up with it in your oil pump screen. I have used Rectorseal and had good results.

http://www.rectorseal.com/RectorSeal-No-5.php

Perhaps a big rubber O-ring would do the trick....with a little GREY hi torque gasket maker on top of that...if needed.

My tube is loose too. They should stick really well when tapped into the block. I think I would have to replace it to get it to fit tight. However, the strap on it that attaches to a pan bolt, keeps it in place. Does yours have the strap on the side?

The draft tube on my 235 was loose and kept sliding out, as well. Here's how I fixed it. I took a large ball peen hammer that had a ball diameter slightly larger than the throat of the tube that slides into the block. Then i gave it one or two whacks, but be careful...too many whacks and you will never get it back in the hole. Mine took two and it snugged it right up. Kind of a poor mans pipe expander but it worked! Good luck!

Coffeeman