vent pipe question
- Thread starter len
- Start date
Unfortunately, the road draft tube is very prone to discharging oil and oil fumes, even with an engine with good piston sealing.
I had a similar situation with my 57 with 292 engine after starting it up after rebuild. I ran the engine at around 1800-2000 RPM for about 25 minutes to break in the new cam per instructions from the machine shop who rebuilt the engine. There was a considerable puddle of oil from the draft tube after that run-in. I tried several methods to prevent the oil leakage, including building a bit of a "dam" inside the canister and making sure the drain tube was open, and while it seemed to help, there was always oil spray and dripping oil after a drive.
The method that has worked best for me was to install a PCV valve and completely remove the road draft tube, replacing it with a cover over the original opening. This also requires that you replace the valley pan with one that has the Thunderbird draft tube location (or possibly rework your existing valley pan to provide a hole for the PCV valve). The T-bird valley pan also has a baffle compartment directly under the hole to prevent oil splash from entering the PCV valve and you would need to add that if reworking your original pan. You will also need to provide a vacuum source for the PCV valve (if you have a 4-barrell carb, there are spacer places with a vacuum port available, but with a 2-barrell, I added a tapped hole in the intake manifold directly behind the carb). The PCV valve I chose was for a 1966 Fairlane with 289 engine and it seems to be sized pretty well for my 292 (bored .030 over).
It's a lot of work, but it certainly helps with the oil leaks and also has a side benefit of less of a "gassy" smell in the garage after a drive.
Good luck,
Dave
I had a similar situation with my 57 with 292 engine after starting it up after rebuild. I ran the engine at around 1800-2000 RPM for about 25 minutes to break in the new cam per instructions from the machine shop who rebuilt the engine. There was a considerable puddle of oil from the draft tube after that run-in. I tried several methods to prevent the oil leakage, including building a bit of a "dam" inside the canister and making sure the drain tube was open, and while it seemed to help, there was always oil spray and dripping oil after a drive.
The method that has worked best for me was to install a PCV valve and completely remove the road draft tube, replacing it with a cover over the original opening. This also requires that you replace the valley pan with one that has the Thunderbird draft tube location (or possibly rework your existing valley pan to provide a hole for the PCV valve). The T-bird valley pan also has a baffle compartment directly under the hole to prevent oil splash from entering the PCV valve and you would need to add that if reworking your original pan. You will also need to provide a vacuum source for the PCV valve (if you have a 4-barrell carb, there are spacer places with a vacuum port available, but with a 2-barrell, I added a tapped hole in the intake manifold directly behind the carb). The PCV valve I chose was for a 1966 Fairlane with 289 engine and it seems to be sized pretty well for my 292 (bored .030 over).
It's a lot of work, but it certainly helps with the oil leaks and also has a side benefit of less of a "gassy" smell in the garage after a drive.
Good luck,
Dave
Everybody probably wouldn't want to do this, but,,I blocked the side vent with a remote oil filter mount. Used draft tube off the back of the valley cover down the frame, it's an F600, there was some oil loss there.
The fix was to use an elbow style "hot rod" breather on each valve cover, that and the fill pipe breather was enough to relieve any internal pressure.
The valve covers breathers put out only the slightest mist, not a problem.
The fix was to use an elbow style "hot rod" breather on each valve cover, that and the fill pipe breather was enough to relieve any internal pressure.
The valve covers breathers put out only the slightest mist, not a problem.
rick55
Senior Member
My 55 Tudor which last saw the road in 1964 had a weird vent system which consisted of a hose from one valve cover connected I think to the manifold. The road draft tube was fitted but had a long tapered bung driven up in side it. The oil cap has a decal on it with Thermidor written on it - I think - from memory. There was some sort of valve connection to the inlet manifold from the valve cover.
I presume it is an early PCV setup. Didn't work to keep the engine clean. The engine was completely sludged up. It didn't look like the engine had ever had an oil change though it had only done 25k miles when it spun a big end bearing.
I presume it is an early PCV setup. Didn't work to keep the engine clean. The engine was completely sludged up. It didn't look like the engine had ever had an oil change though it had only done 25k miles when it spun a big end bearing.
miker98038
Well-known member
I'm a big believer in PCV systems, as mentioned above. Lots of info here if you do a search. One more thought, do you have the filter in the canister? I think that's necessary to intercept the splash and fumes, and route the bulk back into the motor. But the long term is the PCV.
Blackpearleb434
Member
Maybe a bit late on this thread, but I to have a new y block that breathed heavily from the draft tube...I decided to install a pcv set up but didn't want to disassemble the engine to do this, I got some info from another thread and managed to purchase on eBay a billet oil cap that had a pcv valve inside, i put a restrict in the draft tube and use the draft tube as the intake side of the pcv system as it also has a filter in the can, as the air isn't being forced out but sucked in it is pretty clean...looks very neat and works really well and cost $30 it took 30 min the install, 29 of those minute was making the restrictor!!!
Daves55Sedan
Well-known member
People keep asking me "what's that thing sticking down under your car?" IT is a SOCK. Yes I said a sock. I cut the top off an old sock and affix it to the tube with a nylon cable tie. It is still able to breathe, but keeps most of the oil fumes trapped in the fibers of the sock. When one gets too oily, I just replace the sock.