I'm really happy with the 59A in my roadster except for the excessive amount of oil I'm getting from the vent tube at the front of the oil pan. It's not enough to cause a noticeable loss of oil between oil changes, but it collects on the wishbone and makes a mess wherever I park. I thought maybe the vertical tube that runs to the top of the lifter gallery was loose or even that I'd forgotten to install it, but I pulled the intake manifold tonight and it's there. I'm using a stock mechanical fuel pump with a vented cap, so there's plenty of air getting in. The problem is worse when running at highway speeds so I think it's just a lot of mist or spray getting into the vertical vent tube. Anyway, I'm considering installing a PCV valve under the manifold (Navarro dual), but if there's that much oil up there, I'm worried that it'll just plug up. Looking for suggestions, Thanks
You must be running a intake manifold for an 8BA as the 59AB flatheads don't have the front vent tube, you can just remove the tube and plug hole.
Plugging the exhaust hole at the valley or intake will cause pressure in the crankcase. Flatheads need to breath. I would first give the engine a cylinder leak and compression test. If you find excessive blowby and are not prepared to rebuild you will have to live with the leak. Running a PCV will definitely plug up if you have a major leak. Surely you know by now flatheads are like dogs in heat and mark their territory.
"............ I would first give the engine a cylinder leak and compression test. If you find excessive blowby and are not prepared to rebuild you will have to live with the leak." I second that, This is an easy way to figure out if you have a ring/cylinder problem. Had the same problem with a chevy motor recently. It was building so much crankcase pressure it blew the pcv valve right out of the valve cover and oil all over my shop. Tore it down and found broken rings. I installed a pcv valve on my 8BA because i didn't want to run the big draft tube and I am using an 59AB manifold. It works great. It's much easier to just install it on the outside and is really not that noticeable when everything is back together. I found a pvc valve that had 1/8" pipe threads and tapped it into the intake manifold right above vent tube that's at the front right side inside the lifter gallery as you mentioned. The manifold already had a vacuum port to connect to. But if you install it inside, nobody will ever know.
The vertical tube I'm referring to is inside the lifter valley. The manifold isn't opened up for the exterior road draft tube, so it's not really a factor. "............ I would first give the engine a cylinder leak and compression test. If you find excessive blowby and are not prepared to rebuild you will have to live with the leak." The engine is freshly rebuilt, maybe a couple of thousand miles on it by now, but I'll check the compression just to be sure. "Plugging the exhaust hole at the valley or intake will cause pressure in the crankcase." The heat riser holes aren't blocked. It's puzzling............
Another factor is the amount of oil mist in the valley...flatheads seem very sensitive here and anything that increases the load starts to get oil past the valves too. Beyond the essential tube, you must have the rest of the tin, the little shields in the floor of the valley and the tube around pushrod at back. If no pushrod, also, you need an umbrella over the pushrod hole, not because of mythical loss of oil pressure but because a bit more oil can splash up from the cam area there.
The '35-'48 engines do have a front vertical tube that allows fumes from the crankcase and valve chest to flow down directly to the pan-mounted road draft vent. The picture below shows the early (pre-8BA) ventilation system.
Ok that oil is coming from something not right. I would also do a leak test. May be the bottom end. I sure hope your fresh rebuild doesn't need disassembled.
Dropping the pressure in there by PCV might give it enough of a nudge in a good direction...here's how Ford installed PCV into early engines, mostly wartime '42 Merc types. Bob's diagram serves well here: Ford drilled into the right front side of manifold casting on the riser for generator, right about where the little flow arrows turn down into the vertical stack, and hooked in here right above the tube with a 1/4 steel line that ran back to the carb riser and turned up into a vertical PCV (actual valve very similar to wartime Jeep part, might be the same). The top of the PCV was plumbed into very small passages into each side of intake via an adapter below carb just like those used to add a vac port to early Flatheads. The original outlet down on pan was blocked...on some of the engines the hole in the bump was left out, on other pans the entire bump was deleted leaving just flat flange blocking the hole. On an assembled engine...try loosening a few adjacent bolts and sliding in a small piece of beer can buttered with Permatex... At the inlet on fuel pump stand, they substituted a fairly big oil bath air cleaner for the original canned Brillo pad. Very simple and neat setup. Only pics I know of are in obscure WWII military manuals covering various post 1942 armored carriers and artillery trucks.
This is the same way i did it, minus the oil bath breather. Since I am running an 8BA there is no outlet to block at the pan, but that sure sounds like a simple way to do it Bruce. I will post some pictures and the PCV valve number that i used. It taps into the manifold with 1/8" pipe thread.
Thanks for all the replies, they're all helpful getting to to bottom of this. One idea I had that I haven't seen done before is to section that vertical tube so it turns back down. Basically turn it into a loop back toward the bottom. I could then install a spring or Choreboy or other media that would tend to trap the oil and let it drip back down. The loop would also keep oil from splashing into or getting thrown directly down the tube. Kind of like the air-oil separators used in planes. I'm going to pursue the other causes of excess vapor, but this seemed like a possible way to minimize the escape.
The engine is a 59A. Here's a picture of the engine sans intake, plus a couple of close ups of the lifter area. If something is missing or out of place, please let me know. Posted using the Full Custom H.A.M.B. App!
I would add in the rear tube surrounding the pushrod area...wouldn't hurt, might help! In the front tube, before you get complicated, how about just a roll of chicken wire or such shoved down the hole a ways, with a simple safety wire to prevent migration, as a place to collect mist into drops. (edit on that...likely what you need is a roll of mesh on outside of the thing with a hat of some kind at the top, so fumes have to go up through the mesh or whatever and turn down under a dome at top)
I also wonder how important the rear tube is. Probably most guys who don't use a mechanical fuel pump will not install the stock rear tube. I put together a 99 Merc engine and didn't use the rear tube as I run an electric pump. The car leaks and mists oil everywhere. I think I'm going to put that tube in when the car gets dug out of winter storage. >>> Looking forward to pics and numbers for Hilltop's PCV valve.
I do not claim to understand the problem...but many people have reported trouble from leaving any tin out of flathead valleys. It seems all the tin works and does exactly what is needed...put it in and all is happy, with valves lubricated and no troubles. Remove a bit from the same engine and it's blue smoke time... I think this may be related to misting as well. Many things about flatheads involve parapsychology and mysticism...believe and it shall work. If you try to fully understand and solve all the problems in a car, hotrods become impossible and you end up with a Datsun Wombat XLE hybrid... OOPS! Too much Coffee and time spent in Philosopher's index this morning!
You crack me up Bruce. I too installed my rear tube in the 34 which has an electric pump. Definitely makes a difference.
I'm using a stock mechanical pump. The housing has a series of baffles surrounding the pump pushrod tube. I thought the bottom of the fuel pump stand had a tube that dropped down. Is that the one you're referring to or is there another one that stays with the block when the manifold is removed?
I checked compressions this evening. All 140 except one at 105. Drained and changed the oil to calibrate the dipstick and it was reading correctly, so not overfilled with only 4 qts in it. This was interesting though. I measured how far the breather/filler tube extends below the intake manifold. Just under 1 1/2". Then measured how far it is from the top of the block to the hole where the fuel pump pushrod is. 2 1/4", so when the intake manifold is installed, there's a 3/4" gap between the tube and the block. (Plus the thickness of the gasket) If that tube is supposed to seat in the block, mine is too short. (Insert smartass comment here) Were they made in different lengths for some reason? I think I remember that the fuel pump pushrods varied in length. Maybe we're onto something..... Posted using the Full Custom H.A.M.B. App!
Compression: That's a 25% difference in one cylinder only. Might be worth looking into. Could be a vavle, but if it's a ring or cylinder problem, then that could be causing pressure in the crank case and the oil blowing out the breather. Even if rings are new, maybe they were not gapped correctly and broke after they heated up. Both side and end gap are important. Or maybe that one cylinder had a ring broken during installation, or maybe it was put in facing the wrong direction and is leaking past. Exact same symptom (excessive crankcase psi) with the SBC I just opened up - result of: busted rings. Sorry, probably not what you want to hear. But, even with the engine in the car you can probably remove the oil pan and one head and pull that one piston without too much trouble. Not that it matters, but pretty sure that on the late 59A engines, two neighboring rods share one floating crank shaft connecting rod bearing. So when you remove only 1 rod, the bearing will stay in place. Then just slide the piston out the deck. My filler is also short is short of the block by about the same amount. Bruce probably knows if this is the way it should be or not. <!-- / message --><!-- sig -->
Look at back of manifold...the one for short pushrod is roughly 1" high, the one for long is roughly 2", tubes below differ by 1", part of which recesses into the round casting below.
Good process of elimination project. First check for correct oil level ---Done-- next check for correct air ventilation. Must be air access vent at rear of block thru fuel pump stand, air balances thru the stand tube and the pan vent. After that compression or leak down test. A leak test is some times better as it can isolate leak quicker as to cylinder or valve leak area. That 35 point spread on one cylinder is suspect. That tube at the rear of the block to the intake is just a fume stand and will have a small or no importance on the oil leak from the pan vent. Oil pan vent leak is from exit air picking up oil fog spray from the rotating assembly usually when over filled or excessive compression leakage. Oil film leakage thru the vent is usually a sign of greater internal crank case pressure than external so this pressure has to come from lack of air balance ( no upper intake vent port) or excessive crankcase internal pressure usually from ring leakage.
I removed the road draft pipe. Put pcv valve there. Then made up a fuel pump pushrod dummy.(using electric pump). This needs to fill hole but allow oil to pass around it as it is in an oil gallery. This also has to not contact the camshaft. I had a huge oil filling the lifter valley problem and that solved the problem.
Turns out there are different length filler/breather tube lengths. I located a longer one that when installed will force the circulating air down into the oil pan rather than letting it short circuit through the lifter valley and out. I also modified the exit tube as pictured. This will eliminate any oil splashing out, but more importantly I think it will capture most of the oil out of the vapor and let it drip back into the lifter valley rather than all over my driveway. Posted using the Full Custom H.A.M.B. App!
That way, or just a wrap-around 0f mesh with a domed cap (like a crude 1950's hot rod aircleaner) so dripping happens before the trip down. Does not necessarily address the underlying cause but might well keep tings under control for break-in and tuming.
I put it all back together and took it for a spin. About 20 miles on the freeway. Just as much oil as ever. ARGHH!!! Back in the garage I cleaned it up while it was still warm. Fired it back up and got down on the floor to observe. At low and high idle, not a drop. Revved it up to highway RPMs and pretty soon here's a drop of oil on the floor, then another, then another. Turns out it's leaking at the junction of the oil pan gasket/front oil seal. Sitting still it drops straight down. At highway speed it drips down and blows back right on the oil pan vent. It's hard to see up there, but the location of the drip was not the source. Now I need to drop the oil pan and see what's going on there. One mystery solved. On to the next.
So this takes you on to the next challenge – the front seal. The original version is the two piece rope type. The sleeve on the crankshaft has a spiral on it that wipes the oil inward as the crank is turning. There is also a more modern one piece type seal available that presses into the cam cover/oil pan, this type requires a smooth sleeve on the crank shaft. If you were to mix the old spiral sleeve with the newer one piece seal it will leak. So maybe this is the next thing to check.
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