Hi all, new member........ just got my 48 Super Deluxe sedan all stock....... love it Problem is had a slight leak from fitting on oil filter housing so sorted that problem. Thought I would do oil and filter, took plenty of stuffing around to get the seal on the lid to do it's job, seemed to blow the seal when you turn the engine off, but being a mechanic for ever I persisted and had a win, so I thought. So today took it for a drive into town (15 kms round trip) even stopped and got fuel. Got home and drove into the shed happy. Came out to the shed an hour later started it and drove it forward to the hoist shut it off got out to find an oil puddle and heaps along the floor to the puddle now under the hoist. To me it seems to over pressure on shut off and blow the seal. Can anyone help, it's doing my head in....... thinking about getting rid off the filter.
The supply side to the filter canister is supposed to have a restrictor fitting(usually located at the can) that keeps the majority of oil flow and pressure from making it to the canister. I suspect that this fitting is not there and your engine is overfilling the oil filter can. It’s not a full pressure-full flow filter system. Look for a brass fitting with a small orifice.
Hi again, I removed all the fittings from oil filter housing and the fittings in the block near the oil gauge sender unit and no restrictor. What size should the restrictor hole be ? Thanks again for your help
.060" I believe, I just filled the inlet fitting with solder and drilled it to size. Also check the inside of the lid gasket surface for rust and old gasket that might keep it from sealing. Good luck!
Cheers mate, I just found a couple of threads on the subject and did just read about the size of the hole. Will give that a go. The lid is clean with new seal so will set up the restrictor and should be sweet.. Thanks again for answering....... cheers
Please get back to this thread and let everyone know if this solved the problem (after adding the restrictor that is).
I've heard for years about this restricted fitting on inlet line of Ford canister filters but it makes no sense. The outlet tube in the center of the canister that allows the filtered oil back to the pan has the restriction in it. This is what prevents the loss of oil pressure due to the bypass of the filter. As long as the oil canister has a clean sealing surface and a new gasket, it will not leak. Why would you want to restrict the inlet with a fitting where the dirty oil and contaminants will likely clog it off and make the filter useless?
If you have the restriction in the outlet ,,it will make the top of the canister leak,,,,,from the pressure. The restriction is at the inlet,,,,,from the oil pump end ,,,,,,that is where the pressure is . Then the fitting lowers the pressure to a controlled rate and the filter and canister can handle the oil without blowing out . Here is the restriction orifice fitting from my Mercury,,,,,it is the brass piece,,,,the oil pressure sender is in top. Tommy
Unless the inlet hole is smaller than the outlet hole, pressure will build. Take a look at the outlet and I guarantee it is smaller than the inlet fitting. The canister is built to seal and hold pressure but a new gasket and clean surfaces are required. A Napa 1006 filter comes with two different gaskets so you have to choose the correct one. I have 60 psi at start up on my 59ab and my filter doesn’t leak a drop. These filters are very effective as long as they are allowed to work. Look in the bottom of the unfiltered side when it is filter change time and you won’t ever want to run without one.
The inlet fitting is normal size,,,,,but,,,inside the fitting it is only drilled to a .060 size,,,,,to reduce the pressure. The outlet is normal size though and through,,,,,at least on a Mercury . And ,,,,if the fitting is factory and hasn’t been changed . Also,,,,,if the outlet is smaller,,,,,,how can the filter do its job . The oil is pushed under pressure through the media,,,,,,after the media,,,,,there is no need for pressure. Tommy
The point of having the restriction after the filter is that the oil won't have any contaminants to clog the orifice unlike the unfiltered oil at the inlet. Canister filter elements are very effective. I don't know the micron filter sizing but I understand that the canister filters have a finer sizing than full flow filters because you aren't trying to pass all of the oil flow through it continuously.
On 1940s Fords the restrictor was on the inlet side of the filer. Sometimes there was a fitting that had the sender and the restrictor at the inlet side of the canister. The restrictor fitting is on the inlet side of my 1951. It’s my understanding that the purpose of the restrictor before the filter is about volume rather than pressure. The outlet that feeds the filter is main oil gallery. It’s restricted before the filter so the bearings are not starved of oil while the filter fills. The outlet side simply drains back into the side of the block.
As others have said; the restrictor goes on the inlet side of the filter housing... both to reduce flow into the filter and pressure in the filter housing. If you've managed to pump 60 lb. pressure into the filter without leaks you've been lucky. I did it with one of these filters on an early Cad 331; had to go through all kinds of gyrations to keep it from leaking. Finally got smart and installed the restrictor in the inlet line; problem went away.
Again, specifically for a 59ab Ford filter and not a GM or Chrysler or whatever else, there are two .055" restrictor holes on the outlet tube; one high and one low. These canisters are built to hold pressure, there is no luck involved. This may be a different situation on other makes and models but for as many Ford flathead runners that there are on this site, it is not in their best interest to follow parroted information from Google searches and blanket statements about bypass filters in general. Ford was smart, they knew that putting such a small hole on an inlet could allow the line to be plugged thus rendering the filter useless.
If you can plug a .060 hole, you've got major problems in your engine. If you check parts books, they clearly show a restrictor fitting on the inlet to the filter housing.
I’m sorry Justin , Don’t be angry . Flatjack knows a great deal about Flathead Fords,,,,,he and many others here . Yes,,,,the inner tube of the canister does indeed have two holes from the factory. I think mine measure at about.060,,,,,,. However,,,,the inlet line had a fitting plumbed into it,,,,,it screws into the feed line . And that fitting has a small orifice drilled in it . From the outside it looks normal,,,,but the inside is much smaller . No one here is parroting info from Google or anything else . These guys know,,,,they have lived it. My engine is 72 years old,,,,,a lot older than I am . And many things get changed in all those years,,,,,,maybe your fitting has been removed or had been drilled out by a previous owner,,,,who knows. Also,,,,,the manuals show the reducer fitting,,,,it was designed by Ford,,,,like you said,,,,,very smart people . These guys are just trying to help . I always listen to them about Flatheads,,,,,they know . They know more than I ever will,,,,,,because they were driving these things back then . A lot here are over 80 years old,,,,,they have changed all kinds of filters in that time . They know . Tommy
Well apparently I have been led astray by the experts: Flatjack9 - Fordbarn 2-20-2017 11:37 P.M. - "It can also be in the return tube inside the filter." https://www.fordbarn.com/forum/showthread.php?t=215241 If this inlet orifice was part of the original design, why are the fittings unicorns? Why is everyone soldering and drilling their own? Maybe the "guys who lived it" thought otherwise and threw them in the trash. Was is a cure for a problem that didn't always exist? Maybe it was too hard to expect people to replace the gasket and seal up the canister, I don't know but it is worth a discussion. And there isn't any anger here Tommy. I sometimes like to blow up some of the "norms" that have come into being with the popularity of these old engines with today's generation of builders. The canister filter argument is one that is like what kind of oil should we run. People are taking engines that haven't run sometimes in decades without pulling them apart and cleaning all of the sludge and build up out of them. Getting large chunks of crap freed up in this process isn't unreasonable and a restricted oil filter line will the one of the first things to clog. I'm just making a point about the most useful way to run the filter. I know that there are hard and fast rules on forums like this not to go against the grain or the majority of the advise, but we see even with a good guy like Flatjack, there are obviously some ideas that change over time. No hard feelings, okay?
Timely thread, I had my reservoir apart yesterday to paint and checked my fittings. Sure enough the inlet had a very small orifice compared to the outlet. Good to know.
FWIW, the fitting with the restriction is readily available from weatherhead. I got mine from the local NAPA store.
All I can say is that every "unmolested" flathead I've torn down with an oil filter installed had a restrictor in the inlet line; both early and late Flatties... I've been doing this for a bunch of years And full oil pressure going into a flathead filter canister is potentially problematic; whether it's 50 psi from a flathead oil pump or 50 psi from a Cadillac oil pump.
To the O.P. and to warbird1 post above, despite the discussion about whether to have a orifice at the inlet or not, make sure that the flow back to the pan is clear. In an original setup there is another orifice inside of the pan. If this or your outlet tube on the canister is clogged, you will have full pressure in the can which none of us have because the oil is flowing out. The link I posted above has a post by Oldford2 on Fordbarn that shows the inside pan orifice.
I can’t speak to those ,,,,,I only have experience with the 8 BA style engine . My block has a boss cast into it for the return line. A fitting screws into the block outside,,,,and the oil drains back into the pan beside the pan rail . Here is a pic of my block,,,,and the return. And you are right,,,,the return doesn’t have a restriction. Tommy
So now I have to wonder, did the change from the pan return connection up to '48 to the block return connection from '49 - '53 create the need for the inlet orifice? The hole in my pan return line was virtually impossible to see when I cleaned it out. At first, I thought that they forgot to put a hole in it until I found it with the tip of a dentist's pick. Tommy, we may be debating two different scenarios. Maybe Ford, as smart as we both agree that they were, decided to solve the leaking issue due to high pressure in the canister by moving the placement of the orifice with the redesign of the flathead. Flow would still be restricted to prevent oil pressure loss but the canister would not be under as much pressure. But again to the O.P., check that return port at the pan, it is not a straight through hole, it is at a 90 degree angle. You will need a small flexible piece of wire to clear it out. Mine was sludged over on the inside of my pan but you won't have the luxury of cleaning it out with the pan off of the car from what I can tell.
Wow what a discussion I have created, thanks for all your input. So I soldered and drilled the input fitting so far so good, will hopefully give it a good run in the next few days and report back. Cheers all
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