Fellow Flaheads. I recently rebuild my 1939-1942 Ford Flathead motor in my 31 Ford roadster. I've dialed out all the bugs except for two. I'm looking for advice to cure these issues if possible. ONE: My 39-42 flathead motor has rear lybryinth oil slinger seals that work fine at lower rpm. At higher extended rpm the oil starts to puke out this rear slinger seal all over my clutch, starter, exhaust etc. I'm running 25 psi oil pressure at mid rpm, and 50 psi at higher rpm. Hindsight I should have machined my block to accomodate a rope or lip seal. Are there any other options to cure this high volume oil leak? I've tried different 20W50 oil levels and a new breather with no luck. TWO: My car does not overheat but the radiator coolant foams sometimes at hotter temps. (190 to 210 deg F) Coolant and white looking foam purges from the overflow tube and the radiator cap. I'm running a 1933 Ford truck radiator that has been cleaned by a radiator shop. The coolant is new and looks clean as well. The pumps are new from when I re-built the motor. The block was cleaned as well. Any ideas of how to cure this foaming issue. Again, it appears to happen after somewhat extended higher rpm when I come back to low idle or a stop. Thanks, Dowie
Don't have first hand experience with labyrinth type cranks, but a thought or two: Obviously, this ain't right--originally the cars could be run hard without disastrous leaks. One thing might be the little tube that screws into bottom of rear cap... is it there?? I THINK the purpose is to channel the oil collected by the groove to below oil level, and if the hole is exposed to all the thrashing at surface oil can be driven UP the hole... Too much blow-by would be bad--but it would have to be really disastrous, I think. I think you have to take the thing apart and look for bad clearances, debris from assembly in drains, tube, etc. If completely frustrated...seal parts are not in block, they are separate castings. Slinger could be machined off crank to allow rope seal...but that shouldn't really be necessary. Red's has some info on this in "Engine talK" section, search "seal" on their site.
Bruce, Thanks for the advice. I built the motor myself after having the block machined and crank ground. I double checked all of the clearances myslef, and yes, the main cap had a tube coming off to drain the oil back to the pan. The motor leaked like this prior to re-building it. I figured it was the oil pan gasket were it arcs over crank. Same issue even after being completly rebuilt. Thanks, Dowie
Oil foaming is generally caused from moisture contamination. You may have a head gasket leak or worse yet.... i wont go there. Sorry misread.... Coolant foaming too could be a cause of a head gasket leak. Have your coolant checked for combustible containements. Also foaming can be caused by too high of a antifreeze concentrate. Hard water actually fights this. Foam in coolant can result from trapped air in the system, a leak on the suction side of the water pump, an improperly functioning water pump. Foaming may also be caused by a lack of anti-foaming agents in the antifreeze.
I'm thinking at high speeds your engine is building up pressure inside. What breather system are you using..Might need to relieve the pressure inside.. Not sure about the coolent..Lots of reasons..which have already been addressed.. Duane.
Duane, Thanks for the advice on the breather option. Right now I'm using a stock flathead breather though Mac's antique auto. Is there a better one I should try? Thanks, Dowie
The "out" on your breather is the little lump near front of pan...the aircleaner part up top is the "in".
Our freshened 8BA never leaks but it did have a couple of areas it would "weep" a little oil.....not enough to even drip. We engineered a PCV system for it to help keep crankcase pressure down and now we don't even have that weep anymore......and the oil sure stays cleaner, longer also.
I had a similar cooling problem years ago on my 39. If you are using anti-freeze and have a non pressurized cooling system, the anti-freeze will foam and be pushed out the overflow. After thinking all kinds of bad things, I switched to plain water with anti-rust inhibitors and have never had a problem since. I also remember reading about this in an old V-8 Times article.
PCV would likely help here, and would greatly help engine durability in the long run, BUT there's something wrong here that needs diagnosis first!
Guys, Thanks for all the good advice. I just ordered one of the Borg Warner PCV255 valves. Any ideas on how I can quickly hook this valve up to run a test. Other pictures on this site show installing it under the intake manifold on the breather tube after capping it off. I'll also try running water with additives / inhibitors for the coolant foaming isssue I'm having. Thanks, Dowie
The OEM Flathead PCV's of 1941 vintage ran thus: Suction applied from either a plate under carb OR the big 3/8 pipe port used for truck power brakes, depending on vehicle; PCV mounted in front of that (valve should be in attitude used on its OEM home); small steel line, 1/4 or maybe 5/16 brake line type to a fitting up front on right side of generator mount area, right above the vent pipe running down to crankcase. Plug the hole in vent at side of pan. This PCV setup was used on WWII Canadian built military vehicle engines, and I have finally found most of the parts to analyze. I believe USA industrial engines had PCV too, but can't yet be sure. The PCV is for engine durability, mostly, as well as to vent engines idling or running inside an armored box. Your engine will likely benefit in all ways, BUT it still should not have a major leak without PCV--something ain't right.
Bruce, The oil leak or purge is only at extended higher rpm. I'm running a 39 top loader 3 speed and a 31 banjo rear end 3.54:1 so this happens at approx. 50mph +. If I keep the car under 45mph It really doesn't leak too bad. It really leaks bad after extended higher rpm when I come back down to idle. I triple checked all of the drain orifices when I built the motor. Everything was clean and correct. I'm really thinking that the crankcase is developing positive pressure at higher rpm. I just need to find a way to quickly hook up a pcv valve to run a test. Thanks, Dowie
Anything you do to tap vac from both logs and run it to above the vent stack pipe should do fine. Car should run at sustained high speed without severe leaks...maybe rings haven't seated or something?
Bruce, I do have 1/8" NTP bungs coming off my Thickstun highrise intake. Should I run a line from these bungs to the breather tube above the intake? I was confused by the term "tap vac from both logs." Can you please clarify for me....being that I'm a novice and all. Thanks again, Dowie
The manifold is split into two sections, each feeding four ports from half the carb barrels...My feeling id that the PCV should tap into both sides because the system flows air and you want effects equal...look at OEM v8 setups. Ford tapped both sides either via the spacer plate with two drillings feeding one small port or the large tapped hole behind car, also plumbed with a small hole to each side. Most aftermarket manifolds lack a good place like that to plumb one fitting into both sides, so tapping into both branches down below and running the pipes into a T makes sense--the single resulting line to PCV can then be kept entirely in the valley with a rubbwer hose into the vent pipe or brought out into daylight to keep PCV up where you can see it and thence to the front like the stock setup.
Bruce, I checked out my setup last night. My Thickstun intake has a 1/8" NPT bung right in the center of the two highrises. I think I can put a 1/8" NPT port just to the right of my generator on the intake manifold. I'm I getting this right? Should the PCV valve be threaded directly into the generator side of the intake manifold? In other words, which end should I put this borg warner PCV valve on? The novice....Dowie
Route of the PCV: vac port from the two sides of manifold sucks, pulling air through the valve through hole at front of manifold from valve chamber right above forward vent pipe (which goes down to pan area) down in valley. Air enters valve chamber via filtered pipe at rear of manifold, probably some via the labyrinthe too... OLD exit route for air, functionally equiv to the pcv but not Positive, was the vent down at front of pan--plug this. Just tape it or something for now, as the whole shebang is experimental and in development!
Thanks Bruce. I think I got it now. I'll let you know the outcome. I have to wait for my PCV valve to show up in the mail. If plugging the oil pan vent on the right front side of the pan works, (with tape temporarily) how do you reccomend I permanantly plug it? Thanks, Dowie
I'd just carefully clean around the opening and solder on a strip of tin...Ford left hole unpunched on original PCV equipped engines.
Flathead Jack sells a plug specifically for the road draft tube hole. There was also a recent thread where they mounted the PCV in the road draft tube hole, he gave a grommet part number and all.
It's been over six months now of tinkering but I think I finally cured all of these issues. One, running a 6V electric fan on a 6V system just doesn't cut it. These 6V fans just don't produce enough flow though the radiator core. Adapting (adding) a mechanical belt driven fan approx. .250" - .500" from my radiator core made a huge difference. This was quite the task being that my motor originally came with a generator mount fan. I decided to adapt a 42-48 fan and created a custom pulley so that I would clear my mallory distributor. Let's just say it took me weeks to figure it all out and machine the parts / pulleys, but it was well worth it. One other thing I did was to make a set of dummy thermostats for the summer. These dummy thermostats consisted of thermostats with the bottom spring and heat sink cut off. This produced an approx. .625" dia orifice for the coolant to flow through. This kept the coolant flow speed a little bit slower than no thermostat giving it more time in the radiator core. As for my oil leak, I belive two things cured it. One, I installed a PCV valve. Two, after pulling my motor I found a gasket that had slipped out of place. The gasket that arcs over the rear main bearing cap had shifted out of position towards the flywheel, which allowed oil into the bell housing. This must have happened some time during the break in period after I re-built the motor. My oil and cooling issues have been corrected for now. Thanks again for all the help guys. Dowie
Hi, thanks for the update!!! I like your fan setup alot! Do you have an extra pulley laying around? How did you route that PCV system ? Regards Michael
Flathead cooling: make certain your timing isn't too advanced, always run thermostats, shroud your fan
I don't have an extra pulley laying around but here's what I did. I bought a 1941 crank pulley on ebay. This crank pulley has the flange on the outer end with four 5/16-24 threaded holes. (intended to mount a crank fan to) My pulley design is to accommodate a 42-48 fan assembly that mounts to your intake manifold front stud. I designed the new pulley to attach to this 1941 crank pulley while concentricly locating on the inner bore of the 1941 crank pulley. The spacing of the new pulley is just enough to clear a mallory distributor by .1875". The attached blue print shows the assembly if anyone wants to make one. I came up with this solution after finding out that nobody (that I could find) makes a flathead crank / fan pulley that clears a mallory distributor. As for my timing effecting my cooling. I played around with this about a year ago as well. I'm confident that my timing is right and that it's not too advanced. Dowie
Here's my PCV valve set-up. The arrow to the left is the intake vacuum connecting point under my Stromberg 97 carburetors. The arrow to the right is were the PCV valve taps into the front valve galley section of my intake manifold. I used the PCV valve NAPA Echlin 2-9337. This PCV valve was for a similar displacement motor, and it has a 1/8" NPT male on one end and a 3/8" hose barb on the other end. It was smaller than the borg warner PCV255 that was reccomended to me by others. I've been running it for one season now and it's been working great. Dowie
I took the pcv off and went back to draft tube pcv was causing oil to file plugs and engine leaked everywhere not a leak one now plugs running clean happy engine now. added breather to fuel pump stand also
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