FH V8 oil pan

C

Cap'n Dick

Junior Member
My oil pressure went from 30 to 20 or less at idle. Hate to remove the oil pan, but plan to drain the oil and would like to remove the big inspection plate at the bottom or the pan. In my online research, I read about a case where that plate was removed, but couldn't be reinstalled because there were bolts on the outside of the pan holding it on. Nuts on the inside, so there's the problem I'm hoping to avoid. Can that plate be removed and reinstalled without problems if everything is original? I'd like to clean the bottom of the pan and clean the oil pump screen. Any suggestions? Thank you This is a 1950 F1 pickup.
 
Do you see the heads of bolts or nuts on the bottom of your inspection plate? Originally there is a circular ring with threaded studs inside the pan with the studs pointing downwards and nuts are placed on from the bottom. If you see the heads of bolts, the ring isn't there, if you see nuts you have a good chance it is as original.
Terry
 
My cleanout plate (C69A) is the large oval type. Studs screw into a steel plate that surrounds the opening and nuts secure the plate to the pan.
 
Some pics.
 

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Thanks for the replies. There are nuts on the outside of the plate, so I'm going to assume I can remove them and remove the plate without running into any hidden problems. I'm hoping that I can remove the plate and clean the inside of most of the pan. Really hoping that can clean the oil pump screen. Even better, hoping that I can remove the oil pump. Any thoughts on that? Thanks again.
 
Is your cleanout plate circular?
You could loosen just one nut, spin it down a 1/8" and try to push the stud and nut upwards, if they go up they are nut and bolt. Not as original ring with studs that are attached to the ring.
I don't think you can remove the oil pump without removing the pan, but the screen is accessible thru the cleanout plate.
Terry
 
Good idea. It's a round plate. Hope I can clean the screen. Hope that helps with the oil pressure. Worth a try. Thanks again.
 
From my experience you get very limited access through the 8RT oil pan inspection cover. You will be able to remove the screen.. if you remove the plate, put several washers and a nut on each stud, and lightly tighten them. This is to prevent the surfaces between the plate with the studs on and the oil pan from being disturbed.
20 PSI at idle isn't low.
 
I will replace the nuts before I start to disturb things in the pan. Good advice. I got concerned because the pressure has always been 30 at idle. The only work that I've done in the last month is to replace the gas tank and replace all of the fuel lines to the carb. Rebuilt the fuel pump. No doubt the original tank from 1950. The fuel filter was full of stuff. I pulled the tank and emptied it. The stuff that came out was anything but gasoline. Pink, and full of misc. particles firmly attached to the inside. No idea what it was but decided to replace the tank. When I started the motor after all of that, it ran great, but the oil pressure had dropped. Don't see a connection, but don't want to take any chances. After what I found in the tank, I hate to think what's in the oil pan. This was a farm truck from the Chicago. Still has farm dirt on the frame. Very original. I've completed many hours and years of restoration work and hope to add some miles before winter. I'd add a photo if I knew how. Thanks
 
The only specs I have ever seen for flathead oil pressure are in various older MOTOR manuals (the big blue ones). They show operating oil pressure for 8BA type flatheads should be 57 psi. Since they have 80 pound pumps, this figure is a result of the rating of the spring in the relief valve in the oil pump. Every fresh rebuilt (or good running used) engine I have had ran at this figure. No hot idle figure is given, but I have always experienced 25 psi. I agree that 20 is plenty, but also share your concern with the sudden drop. I agree with "Vincent", and believe an oil change is in order.
 
I had a old used flathead i got from someone and i pulled the pan and the screen was clogged solid with dried oil sludge. soaked it in industrial solvent and it didn't touch it. i ended up using oven cleaner and it worked great. i am glad i didn't try to start the engine before i cleaned it out.
 
Thanks to everyone for all of the help and advice. Plan to start that project tomorrow. I'll post the results. Hopefully it's all good news.
 
Update on my 50 F1. Drained the oil. I think it was oil. Not sure what that was. Removed the plate at the bottom of the pan. More sludge. Cleaned everything I could get to and let it drain for 2 days. Pulled the screen. Very clean. Nothing to clean. Replaced the screen and inspection cover. Replaced the oil filter, which was possibly the main reason for the low oil pressure. Lots of crud. Cleaned out the canister that holds the filter. New filter. New oil. Circulated the oil. Started the motor and it went to 30 at idle, which is where it has always been. I'm happy. Runs great. I suspect that the sludge has been in there for quite awhile. Haven't changed the oil for quite a while, since I've been doing all of the restoration. Not many miles in the last several years. Maybe 25 miles. Now I can drive it. Thanks to everyone for their input. All very helpful. Cap'n Dick
 
With that much sludge, I just have to make sure; you haven't been using non-detergent oil have you?
 
I used Castrol GTX 10 w 30. Not detergent. Also not synthetic. Says that it has superior sludge protection. Higher than industry standards. Sound good? Thanks for checking. They didn't have much non synthetic oil, which is what I prefer for the old truck. Told me that it's getting harder to find.
 
Sounds good, but I'll bet it's classified as a detergent oil. I get the desire to use dinosaur oil instead of synthetic, as I have heard that synthetic will leak more easily. My only experience is that when I ended up with a spare case of Mobil-1 15W/50 from my race car. I used it up in my '51 Ford with no problems. It still leaked a drop or two, but no more than with regular oil. Probably the weight.
 
I have read that synthetic oil is not as slippery as "REAL" oil, and is not recommended for flat tappet motors.
 
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