Road Draft Tube Conversion - Results!

[bbogue]

When my rebuilt 390 engine was reinstalled in my 61 I converted the road draft tube to a PCV system. The PCV system consisted of fittings, PCV and PCV tubing from the the old road draft tube outlet at the back of the intake manifold to a fitting in the manifold in front of the carburetor. The system was almost completely horizontal. This is very similar to the early PCV systems installed on some 61 TBirds. To combat oil burning since the rebuild, I have been testing oil restrictors in the heads (currently at 0.086") and was about to restrict some more when I discovered oil downstream of the PCV. I considered going back to the road draft tube to test my suspicion that my oil burning was PCV related but decided not to when I considered how much residue probably remains in my engine and exhaust system from 500 miles of running while burning 1 qt to 200 miles. It might take a while to see changes in the blue smoke I see when I rev the warm engine. So, I improved my PCV system by adding a JLT PCV prefilter to my system. This prefilter is just a small canister that contains what I think is a metal mesh prefilter designed for a Ford 5.0L. I positioned the prefilter as high as I could above the outlet for the crankcase vapors to give as much opportunity as possible for oily vapors to condense and flow back into the crankcase before reaching the prefilter. Hopefully, most of the remaining oily vapors would be "encouraged" by the pre-filter to do likewise. By orienting the prefilter as high as possible it enabled me to orient the PCV more vertically, like they were in the 62-63 TBirds. I'm not sure if the PCV cares if it is horizontal or not but I wanted to leave as little as possible to chance. I took the car out for a 15 mile run and am encouraged by the results. There is no oily residue at the PCV but there still is blue smoke when I rev the warm engine. Residue? Before passing judgement on my PCV mods I plan to give it a hundred miles or so to burn out the residue and maybe run a can of Seafoam through the engine as well. So far, so good.

Bill

[ABQTBird]

It might take a while to see changes in the blue smoke I see when I rev the warm engine.

This sounds far worse than a PCV problem. The Positive Crankcase Ventilation system is merely supposed to collect oil vapor and blow-by gases and burn them via the intake manifold. If you are seeing blue smoke out of the exhaust at any time when the engine is running, you have something far more severe going on, especially with the amount of oil you say you are burning. Blue smoke in the exhaust is more indicative of a piston ring or perhaps a valve guide problem. If this engine was recently rebuilt, you should not be burning that quantity of oil. I would do a compression check on each cylinder. Do you have any kind of warranty from the engine rebuilder? Can you take it back to them and show them what is going on? I hate to say it, but what you are doing is a Band-Aid for a more serious disease.

[bbogue]

Thanks Tom. Compression was a little lower than expected but likely the result of an overlapping cam and/or thicker head gasket. They were also pretty uniform across all cylinders. A leak down test was excellent. I have my fingers crossed that I have found my issue. My brother-in-law's car had a PCV that did not shut at idle (highest vacuum) and he had smoke. I note with interest that Ford in the 60's moved the PCV source connection from the rear of the manifold to the valve covers. Later valve covers are baffled or screened. The 62-63 TBirds had a U-shaped tube oriented at about 45 degrees from the horizontal. I think this may have been an effort to improve the 61 system and deal with heavy oil vapors before the PCV. 61's with PCV did not have this tube. My TBird had no baffling/screening (or U-tube) before the PCV so I think it is reasonable to expect more than normal oil vapors from this system. The PCV prefilter appears to be working. I am encouraged. Please don't rain on my parade yet. I think I have stopped a source of the oil burning. Is there another one? The dipstick and future drives will tell. If this is not the source of my oil burning issue I will figure it out eventually. No, no warranty, a handshake and a verbal that he would stand behind his work. There were other issues and we will likely end up in court. I'm putting that off until I figure out the oil burning issue. He as well as some experts on the FE forum got me started with the oil restricting...commonly necessary I hear for non-stock rebuilds. It still could be oil rings or valve seals but I am trying to do everything I can before I go there. Thanks.

Bill

[smorgasbird]

I installed a PCV system in my '61 by mounting the valve in a grommet in the passenger side valve cover. I ran a rubber fuel line to the PCV port in my carb- an Edelbrock 4bbl. Like you, I had trouble with oil getting past the valve and being burned in the intake. So I went to the local Harbor Freight and bought an air tool line filter. I threaded a 3/8" nipple into each end, cut the PCV hose and inserted the filter. I zip tied it to the support (runs from firewall to shock tower) to keep it off the engine. When the clear bowl gets about 1/2 full I simply unscrew it and dump it out- no problem. There is an after market filter especially made for this purpose that I saw on a Mustang- which gave me the idea- but I wasn't about to spend $100 plus for something I could make for less than $20.
BTW you will need to get some kind of baffle under the valve to prevent it from sucking so much oil through it. I used one I found in a Jegs catalog part # 555-50128 You'll have to drill a large hole in the cover and be careful about the placement so it doesn't hit a rocker arm. Mine works fine- no clearance problems.

[bbogue]

Thanks for the information Mike. A few questions...
What PCV are you using and how is it oriented? Does it thread into your carb?
When you first installed your PCV and had oil issues, can you describe what you saw with respect to smoke and can you approximate how much oil was being burned in this way? I don't see blue smoke except when rev'd (warm) from idle. Oil usage has been about 1 qt to 200 miles.
Good idea with the air/oil separator. I looked into this as well but opted for the PCV pre-filter, first. If I have to go this route (in addition to my pre-filter), I will probably use a JEGS air/oil separator, about $50.
Going to the valve cover as source for the PCV will be last resort for me, not that I am trying to keep my car pristine original. I just cringe at the thought of cutting into my Thunderbird valve covers. If I were to go this route, my JLT PVC pre-filter is designed to be installed in a grommet on the valve cover. This would provide the same function as a baffle but since it would sit on top of the valve cover, there should be no interference with rockers.
Finally, how did you cap the old road draft tube opening at the rear of the intake?
Thanks again.
Bill

[bbogue]

I was asked to post pictures of my PVC pre-filter/PVC arrangement. Here they are. Please don't judge me too critically. I'm looking for function (eliminating oil in the PCV) right now. Pretty can come later.






Thanks.

Bill

[ABQTBird]

Well that looks nice. I can't quite tell how you have it connected in the back of the manifold. Where is it connected to the vacuum in the front?

I was just thinking, do you think your valley pan might be missing? The only way to tell is to take the manifold off and that certainly is a pain.

Here is my version that I did before I bought a used system from Pat Wilson.
http://www.southsandia.com/forum/website/pcv.html

[bbogue]

Thanks Tom.
I was able to get most of the parts for a 62-type system from eBay and Jim Wulf. I had planned to convert to a 62 system. Unfortunately, 61 manifolds appear to be taller than later models and would not accomodate the 62 spacer due to hood clearance issues. I installed the nipple on the rear of the manifold from the 62 system to which is attached PCV hose. The system gets vacuum from a fitting on the manifold in front of the carb like the 61 PCV system (mostly CA cars I have heard). Yes, I am pretty sure the valley pan is installed. No rocker tins, though. They would not fit with my rockers.
Did you run the PCV system shown at your web link long enough to know if it pulled oil from the crankcase? Thanks.

Bill

[ABQTBird]

Did you run the PCV system shown at your web link long enough to know if it pulled oil from the crankcase?

No, actually I didn't. I installed it, but then found a good deal at Pat Wilson. They charged me $85+shipping including the carb base which I told them I didn't need. Now I have a friend that I am helping to restore a 62 Roadster. I emailed Pat Wilson and they wanted $175 this time. So we will leave the Roadster alone for originality. I haven't driven it very many miles lately, as I have the front suspension out of whack. I need to do the right side and get it aligned.

[GeorgeG]

Just to add my two cents worth here, here's a pic of the PCV system I made for my '61 to mimic the California version. Uses a rear manifold tap that Jim Wolfe found for me and a Fram FV100 PCV valve plus some stainless tubing and brass fittings I had around the garage. Manifold is now back on the motor and I'm waiting for a nice non-rainy/non-cold day to roll the car outside and start her up for the first time in a few years. Once that happens I'll see if I run into the smoke problem that you're having, Bill.

George

[bbogue]

Very neat, George. I hope you don't have oil burning issues.

Bill

[smorgasbird]

Bill, I can see by the pics you posted that we have two very different set-ups. First, I installed an Edelbrock aluminum intake that has no fittings or openings for the PCV system. As I mentioned earlier, I drilled a hole in the RH valve cover and installed a threaded baffle. I inserted a piece of heater hose into the opening of the baffle and installed a press fit type of PCV valve into it. Then I ran a 3/8" fuel line to a small hose fitting I installed in the base of my Edelbrock carb. And, of course I put the in-line filter in the hose between the valve and carb. I installed the filter because it was burning a small amount of oil- not nearly the amount yours is burning. The filter took care of the problem.
As for your intake- isn't there supposed to be a "steel wool" type of filter in the rear opening where the PCV connects? The original intake on my '61 had a California vehicle type of PCV system with the filter material and a right angle connector that was press fit into the rear of the intake (just like the one in George's pic- but not near as nice looking). I ran the Bird with that set-up for a year or more with no problems.
Here's how mine is set up:

[bbogue]

Mike, thanks for responding.
I guess the fitting at the rear of the intake might have had "steel wool" in it at one time...it didn't when I received it...likely long gone. If it was installed with these fittings originally, it seems to me it would be a little difficult to clean and not something I want to duplicate. My PCV pre-filter should do the job of this steel wool or your baffled fitting at your valve cover. I may experiment with its location, perhaps nearer the inlet from the crankcase, if I start to get oil at the PCV. I am reluctant to change to a different PCV than stock without knowing more about how to do so without affecting function. The vacuum source is a concern, too. Yours at the carb would distribute vapors more evenly to the cylinders while my "stock" location would seem to distribute only to cylinders fed by that runner. But you said your 61 system worked OK so I will assume that's OK for now.
I plan to give my system a few miles to prove itself, or not. If it seems to still be passing oil, it's likely I will install an air/oil filter. If it seems to be working OK but my oil burning continues my next steps are one more iteration of smaller size oil restrictors in the heads followed by positive-type valve stem seals. Fun stuff. My friends say I need to install zippers in my valve covers, they're on off so much!
Thanks again for the info.

Bill

[GeoffInCarlsbad]

Looking at the Shop Manual, page 1-21, Figure 30, here is what the PCV (Crankcase Ventilation) should look like on the 1961 390 FE. (Click on images to enlarge).



A top view on page 1/23 Figure 32 looks like this:



On my 1961 Betty Bird, I have a Vacuum Exhaust Pump Connection (bolt) sitting in the Vacuum Pump Connection, nothing attached.




Right now, I have the Road Draft Tube coming from the Crankcase Ventilation Outlet.

So here's the question: Are there any reasons why I cannot convert the Road Draft Tube to the PCV as described in the shop manual? I suspect I can buy the correct parts, though I am having trouble with the Vacuum Pump Exhaust Tube Connection. No one seems to have that.

And George, from your post above, what were your results? For that is what I am looking to do as well per the manual.

~geoff

[bbogue]

Geoff,
My PCV system (pics in an earlier) seems to be working well now. My oil burning turned out to be valve seals. I found the part for the hose connection on front of the carb at a local fastener store. Best of luck.

Bill